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. 2003 Mar;131(3):477–483. doi: 10.1046/j.1365-2249.2003.02070.x

Monocyte-derived RANTES is intrinsically elevated in periodontal disease while MCP-1 levels are related to inflammation and are inversely correlated with IL-12 levels

S J Fokkema *, B G Loos *, U Van Der Velden *
PMCID: PMC1808657  PMID: 12605701

Abstract

Bacteria colonizing tooth surfaces are essential in the induction of an inflammatory response in the periodontal tissues, but do not cause periodontitis in everyone, implicating differences in the host immune response. These possible differences were studied using lipopolysaccharide (LPS)-stimulated whole blood cell cultures (WBCC), which revealed a down regulation of monocyte derived interleukin-12 (IL-12p70) in untreated periodontitis patients and an up regulation after therapy. IL-12p70 is a crucial factor in the differentiation of Th1 cell responses. Since CC chemokines are able to influence the T cell differentiation via cytokine secretion in antigen-presenting cells, the production of CC chemokines in periodontitis was evaluated. Therefore WBCC were stimulated with LPS from Escherichia coli for 18 h and the levels of IL-12p70 and CC chemokines were measured in the supernatants by ELISA. Untreated periodontitis patients released 2 fold more RANTES (regulated on activation normal T cell expressed and secreted) (P = 0·01) and lower levels of IL-12p70 in comparison to controls (P < 0·05). A trend towards higher levels of macrophage chemoattractant protein-1 (MCP-1) (P = 0·07) was also seen in untreated periodontitis patients; while similar levels of monocyte derived chemokine (MDC) and macrophage inflammatory proteins-1α and -1β (MIP-1α and -1β) were found. After periodontal therapy no changes were seen with regard to MDC, MIP-1α, MIP-1β and RANTES, whereas the MCP-1 levels decreased (P < 0·05) and the IL-12p70 levels strongly increased (P < 0·01). The data showed a consistent inverse correlation between the levels of MCP-1 and IL-12p70, and their proportional changes after therapy correlated with the clinical inflammatory response after therapy. This indicates that the disease state regulates the release of IL-12p70 and MCP-1 in E. coli LPS-stimulated WBCC. In contrast, the persistent augmented levels of RANTES after therapy are suggestive for an intrinsic behaviour.

Keywords: periodontitis, monocytes, IL-12p70, MCP-1, RANTES

Introduction

Periodontitis results from the inflammatory response of the host to the bacterial challenge in the gingival crevicular area [1]. Although bacteria are essential in the induction of the inflammatory response in the periodontal tissues, they are insufficient to cause destructive periodontal disease [2]. It is generally acknowledged that not everyone is equally susceptible to the disease [1,2], which implicates intrinsic differences in the host immune response.

In the inflammatory infiltrate, which develops in the periodontal tissues, T- and B-lymphocytes outnumber the antigen-presenting cells (APCs), i.e. monocytes, macrophages and dendritic cells [3]. Nevertheless, APCs have an important regulatory role in the development of immune responses in general [4]. It is commonly acknowledged that inflammatory mediators present at the initiation of the immune response determine the differentiation of Th1 and Th2 cells [5]. In this respect IL-12 and PGE2 are important factors: IL-12 induces the development of Th1 cells producing high levels of IFN-γ, while PGE2 either selectively inhibits IFN-γ production directly or indirectly via an IL-12-antagonistic way and thereby favouring the development of Th2 cells [6–8]. The knowledge on the role of APCs is based on experiments with the peripheral blood precursors, i.e. the monocytes, either isolated or in whole blood cell cultures (WBCC) and resembles the in vivo situation [8–10].

Previous experiments in our laboratory with LPS-stimulated WBCC have shown that periodontitis patients release lower levels of IL-12p70 (the biological active heterodimer of IL-12) and higher levels of PGE2 compared to control subjects, whilst the levels of IL-10 were comparable [11]. Interestingly, after periodontal therapy the release of IL-12p70 in LPS-stimulated WBCC from patients strongly increased, whereas the PGE2 to IL-12p70 ratio decreased (Fokkema et al. unpublished observation). Based on the fact that WBCC stimulated with relatively low concentrations of LPS specifically reflect the behaviour of the monocytes [8], it was proposed that APCs from untreated periodontitis patients exhibit a type 2-promoting phenotype, which diminished after periodontal therapy. Indeed, in untreated periodontal lesions T cells express higher levels of IL-4 and IL-5 mRNA and produce more IL-4 and have a lower IL-2/IL-4 ratio compared to controls [12–14]. These observations for periodontal disease are in parallel with other studies that indicate a similar association between Th2 cytokine-biased immunity and a type 2 profile in APCs of patients suffering from HIV infection and atopic allergy [15,16]. Both latter studies show that the monocytic release of IL-12p70 is also lower in patients compared to controls. However, the reasons for this depressed production of IL-12p70 by peripheral blood monocytes in patients with untreated disease is still largely unknown.

Chemokines, well known for their role in directing cell movement, have also been shown to influence the direction of T cell differentiation. A growing body of evidence indicates that CC chemokines have indirect effects on T cell differentiation through their effects on APC trafficking or APC cytokine secretion, as well as direct effects through actions on the differentiating T cell [17]. Recently, it has been shown that a selective set of CC chemokines is able to suppress the production of IL-12p70 by human monocytes, and in that way participate in the development of T cell-mediated immune responses [18]. Therefore, the present study investigated whether the release of CC chemokines in LPS-stimulated WBCC correlated with the levels of IL-12p70-from periodontally healthy controls and untreated and treated periodontitis patients.

Materials and methods

Study subjects

Nineteen periodontitis patients (mean age 37 years; range 26–45 years), who were referred to the Department of Periodontology of the Academic Centre for Dentistry Amsterdam (ACTA), volunteered to participate in the study. The selected patients displayed periodontal bone loss>1/3 of the root length at ≥2 teeth per quadrant of their mouth as visible on dental radiographs. In addition, only non-smoking patients were selected, i.e. who had never smoked or had ceased smoking more than 10 years ago. A control group of 19 non-smoking subjects was selected on the basis of absence of bone loss on dental radiographs. The control subjects (mean age 37·5 years; range 27–45 years) were recruited from patients of the ACTA referred for the treatment of dental caries. The patient group included 6 subjects with a mixed racial background and the control group 5 subjects. All participants were free from systemic diseases and usage of medication, and reported no clinical symptoms of bacterial, viral or parasitic infections at the time of the study.

Eight out of the 19 periodontitis patients volunteered to participate in a specifically designed treatment protocol, including the use of systemic antibiotics. This patient population had a mean age of 34 years (range 26–42 years). Approval by the Institutional Review Board on human studies was obtained and all subjects signed an informed consent.

Clinical procedures

The specifically designed treatment protocol consisted of oral hygiene instructions, full mouth scaling and rootplaning within 24 h supported by systemic antibiotics for 7 days (Amoxicillin and Metronidazol) and 3 months rinsing with chlorhexidine twice daily. To evaluate the effect of the periodontal therapy, full mouth clinical measurements and microbiological samples at 4 selected sites, i.e. the deepest site in each quadrant of the mouth, were performed before as well as 3 months after therapy. The sampling and culturing procedures were performed in a standardized way, as described previously [19]. In brief, after the removal of supragingival dental plaque with a curette, two consecutive paper points were inserted into the periodontal pocket and left in place for 10 s. The paper points were pooled and immediately suspended in Reduced Transport Fluid and subsequently processed in the laboratory on the same day. The presence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Bacteroides forsythus, Prevotella intermedia, Fusobacterium nucleatum, Peptostreptococcus micros and Campylobacter rectus was determined.

Whole blood cell cultures

Venous blood was collected by venepuncture in sodium heparin-containing blood collecting tubes (VT 100SH tubes; Venoject; Terumo Europe, Leuven, Belgium) of all subjects participating in both sets of study groups. The blood was diluted five-fold in endotoxin-free RPMI 1640 medium containing L-Glutamine and 25 mm HEPES (Gibco BRL, Life Technologies B.V., Breda, the Netherlands) and was supplemented with 100 U/ml penicillin and 100 µg/ml streptomycin. The diluted whole blood was cultured in duplicate in pyrogen-free 24-well flat-bottom tissue culture plates (Costar, Cambridge, MA, USA) in the presence of 1 ng/ml LPS from Escherichia coli O127:B8 (Difco, Detroit, MI, USA) for 18 h at 37°C. The period between the blood collection and the start of the incubation was 1·5 h. Following culturing, supernatants were stored at − 80°C until determination of chemokine and IL-12p70 concentrations. Previous experiments in our laboratory revealed that WBCC stimulation with LPS concentrations of 1 ng/ml was the most optimal for the production of inflammatory mediators, except IL-12p70. The production of IL-12p70 was only measured at 100 ng/ml LPS, since this cytokine is released in extreme low levels in <100 ng/ml LPS stimulated WBCC. Furthermore, the produced dose–response curves did not differ between patients and controls as well as for patients before and after periodontal therapy.

Venous blood of all participants was also collected in an EDTA(K3) containing tube (Becton Dickinson Vacutainer System Europe, Meylan, France) for the determination of the leucocyte count and differentiation, and were performed in standard automated procedures.

Assays

All used specific monoclonal antibodies, neutralizing antibodies and the recombinant human MCP-1 (macrophage chemoattractant protein-1), MDC (monocyte derived chemokine), MIP-1α (macrophage inflammatory protein-1α), MIP-1β (macrophage inflammatory protein-1β) and RANTES (regulated on activation normal T cell expressed and secreted) were purchased from R & D Systems (Abington, UK). Measurements of the WBCC supernatants were performed by specific solid-phase sandwich ELISA, according to the manufacturers protocol. Interference of plasma and heparin in the ELISAs was prevented by the use of a high performance ELISA buffer developed at the CLB (Central Laboratory of the Netherlands Red Cross Blood Transfusion Service, Amsterdam, the Netherlands). The bounded chemokines were detected using streptavidin-poly horseradish peroxidase conjugate (CLB) and tetramethylbenzidine/hydrogen peroxide as a substrate (Biosource Europe SA, Nivelles, Belgium). The detection levels of the assays were 10 pg/ml for MCP-1, 20 pg/ml for MDC, and 30 pg/ml for MIP-1α, MIP-1β and RANTES. A specific solid-phase sandwich ELISA was also used for the measurement of the IL-12p70 levels, as described previously [8]. The detection limit of the IL-12p70 assay was 3 pg/ml. The chemokine and cytokine concentrations of the duplicate cultures all ranged within the normal intra-assay variability.

Statistical analysis

SPSS package (version 10·0 for Windows, Chicago, IL, USA) was used for data analysis. Data analyses of the log-transformed chemokine and cytokine concentrations were performed by means of an analysis of covariance. The number of monocytes was used as a covariate, as were the gender, age and race of the study subjects. P-values < 0·05 were considered significant.

Results

IL-12p70 and CC chemokine production in periodontitis

In Fig. 1a the released levels of IL-12p70 in the LPS-stimulated WBCC are presented and show for the untreated patients a lower IL-12p70 production in the cultures compared to the controls. With regard to the levels of the MIP-1β, MDC and MIP-1α in the supernatants there were no differences between untreated patients and control subjects (Fig. 1b,c). However, the untreated patients proved to produce almost two fold more RANTES in comparison with the control group (29 ng vs. 15 ng/106 monocytes, P = 0·01). It was remarkable that within the untreated periodontitis group there were patients who produced up to six and eight fold higher levels of RANTES in comparison to the controls. Furthermore, the MCP-1 levels in the blood cell cultures from the untreated periodontitis patients showed a trend towards higher values in comparison with the controls (P = 0·07). In 7 out of the 19 untreated patients the released concentrations of MCP-1 in the WBCC were two to four fold higher compared to the cultures of the controls. In addition, the released levels of MCP-1 in the LPS-stimulated cultures correlated with the released levels of IL-12p70 in the same cultures (r = −0·3, P = 0·02). This indicated a reversed relationship between the production of the CC chemokine MCP-1 and the levels of IL-12p70 in the WBCC: higher levels of MCP-1 correlated with lower levels of IL-12p70.

Fig. 1.

Fig. 1

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LPS-induced production of IL-12p70 (a) and the CC chemokines MIP-1β, MDC, MCP-1, MIP-1α, and RANTES (b and c) in 19 untreated periodontitis patients (▪) and 19 controls (□). The whole blood cell cultures were stimulated with 1 ng/ml LPS from E. coli for 18 h, while the cultures for IL-12p70 were stimulated with 100 ng/ml LPS. Data are means ± SEM and are expressed as IL-12p70 or CC chemokine production per 106 monocytes. The individual data per subject were the mean of two different cultures. *P < 0·05, as determined by analysis of covariance with gender, age, race and number of monocytes as covariates.

IL-12p70 and CC chemokine production after periodontal therapy

The extent and severity of the inflammation in the periodontal tissues from the 8 patients, who participated in the treatment protocol, is clinically expressed as high percentages of bleeding on probing and deep probing depths (Table 1). As can be seen from Table 1 the mean percentage of shallow probing depths increased after periodontal therapy and the mean percentage of deep probing depths reciprocally decreased. On average the bleeding on probing scores decreased from 80% to 20% after therapy. The major periodontal pathogens A. actinomycetemcomitans, P. gingivalis and B. forsythus were no longer detectable after periodontal therapy, whereas at baseline these species were present in the subgingival samples of 3, 4 and 6 out of the 8 patients, respectively (data not shown).

Table 1.

The extent and severity of the inflammatory process in the periodontal tissues before and after therapy in 8 patients

Baseline (mean) After therapy (mean)
PD
 1–4 mm 41% 90%
 ≥5 mm 59% 10%
BOP
 all sites 80% 19%
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PD, probing depths, recorded to the nearest millimetre; BOP bleeding on probing

In order to analyse whether the lower production of IL-12p70 in untreated periodontitis patients is an intrinsic characteristic of their monocytes or acquired as a result of the disease state itself, the production of IL-12p70 was evaluated before and after periodontal therapy. Similar analyses were performed for the release of the selected CC chemokines. After therapy the levels of IL-12p70 released in the cultures of the periodontitis patients increased on average 2·5 fold (Fig. 2a). Interestingly, these levels were now comparable to the levels seen in the control group and statistical testing showed no difference anymore between treated patients and controls (P = 0·7, compare Fig. 2a with Fig. 1a). For the selected set of CC chemokines, only the levels of MCP-1 changed after periodontal therapy, whereas the levels of MIP-1β, MDC, MIP-1α as well as RANTES were unaffected (Fig. 2b,c).

Fig 2.

Fig 2

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LPS-induced IL-12 and CC chemokine production in 8 periodontitis patients before (▪) and after (□) periodontal therapy. For the measurements of IL-12p70 (a) the whole blood cell cultures were stimulated with 100 ng/ml LPS from E. coli for 18 h, whereas the cultures for the CC chemokines (b and c) were stimulated with 1 ng/ml LPS from E. coli. Data are means ± SEM and are expressed as IL-12p70 or chemokine production per 106 monocytes. The individual data per subject were the mean of two different cultures. *P < 0·05, as determined by analysis of covariance for matched pairs with the number of monocytes as a covariate.

Table 2 shows that all but 2 treated patients had decreased levels of MCP-1 after therapy and concomitant increased levels of IL-12p70. Moreover, just the 2 patients who showed an increase in the levels of MCP-1 had in fact no change in the IL-12p70 levels after periodontal therapy. This suggests again, a consistent and inverse relationship between the released levels of MCP-1 and IL-12p70 in the cell cultures. The same 2 patients with increased levels of MCP-1 after therapy also showed less favourable outcomes of therapy, i.e. more residual inflammation (Table 2).

Table 2.

The individual proportional changes in the release of MCP-1, IL-12p70 and the clinical inflammatory response after therapy

Patient MCP-1 IL-12p7 BOP PD ≥5
1 −47% 147% −81% −98%
2 −27%  81% −92% −85%
3 −43%  75% −84% −89%
4 −67% 314% −92% −79%
5 −24% 227% −79% −86%
6 −41%  97% −86% −70%
7  9%  2% −37% −89%
8  32%  −4% −74% −47%
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BOP,bleeding on probing; PD, probing depths, recorded to the nearest millimetre.

Discussion

The present study focused on the release of a set of CC chemokines and IL-12p70 by peripheral blood monocytes in E. coli LPS-stimulated WBCC, which were derived from periodontally healthy controls and untreated and treated periodontitis patients. The choice for a nonspecific stimulant in activating the WBCC was motivated on the basis of previous experiments, which revealed that not all patients and controls were always colonized by the same major periodontal pathogens. Moreover, since many studies within the field of periodontology and in other areas of research concerning distinct inflammatory diseases, use the common available and highly purified source of E. coli-LPS to activate peripheral blood cells [8, 11, 16, 20, 21, 22, 23], it facilitates comparisons with other studies. Although WBCC have the disadvantage of the complexity being a mixture of cells and plasma, it has been very well documented that WBCC stimulated with LPS specifically reflect the behaviour of the monocytes as has been shown in parallel cultures of whole blood and freshly isolated monocytes as well as in kinetics [8, 16, 21, 22, 24, 25, 26]. In addition, it was shown that the purified monocytes but not CD14-depleted peripheral blood mononuclear cells (PBMC) or granulocytes were responsible for the production of cytokines following the stimulation with LPS [8,16]. Furthermore, the reflected performance of monocytes in LPS-stimulated WBCC was found for relatively low levels of LPS, since the cytokine production by neutrophils required much higher amounts of LPS [25]. Above that, a recent paper has clearly demonstrated that indeed the monocytes orchestrate the LPS responses in whole blood due to the presence and high expression of the obligatory receptors on their cell membrane: CD14 and Toll-like receptors 4 and 2 [27]. Therefore it is highly likely that the levels of the inflammatory mediators found in the WBCC, which were stimulated with relatively low levels of LPS, reflect in the present study the behaviour of the monocytes. For this reason the cytokine and chemokine levels were expressed per number of monocytes.

The case-control experiments revealed that the production of RANTES was higher and the levels of IL-12p70 lower in periodontitis patients, while the levels of MDC, MIP-1α, and MIP-1β were comparable between subject groups. The values of MCP-1 were somewhat higher in the patients then in controls, but failed to reach the level of significance. The aim of periodontal therapy is to restore periodontal health, which is characterized clinically by shallow probing depths and low bleeding scores and microbiologically by a low percentage of periodontal pathogens [28]. The present periodontal therapy substantially reduced the clinical inflammatory process in the periodontal tissues and resulted in decreased levels of MCP-1 and increased levels of IL-12p70 in the stimulated cell cultures. The levels of MDC, MIP-1α, MIP-1β and RANTES were unaffected by the therapy. These results suggest that MDC, MIP-1α and MIP-1β have, at least in E. coli LPS-stimulated WBCC, no particular relationship with periodontitis.

The suppressive effect of MCP-1 on IL-12 was first shown in mice. The treatment of mice with MCP-1 resulted in a reduced production of IL-12p70 within mucosal tissues [29]. In addition, in a mouse model of endotoxic shock, the exogenous administration of MCP-1 significantly protected mice from endotoxin-induced lethality [30]. The protection correlated with low IL-12p70 levels in serum and resembled the protection observed after anti-IL-12p70 treatment [30]. Recently, MCP-1 has been shown to suppress the production of IL-12p70 in activated human monocytes, while other chemokines, such as MIP-1α and RANTES, seem to have no or little effect [18]. The results of the present study are in line with this latter finding that the released MCP-1 molecules in the WBCC could suppress the levels of IL-12p70 in the peripheral blood monocytes. Moreover, the levels of MCP-1 correlated inversely with the levels of IL-12p70 in the cultures from the periodontally healthy controls and the untreated patients as well as the treated patients. Therefore, the lower IL-12p70 levels in untreated periodontitis patients are transient in nature and correlate strongly with the changed levels of MCP-1 in the WBCC. Consequently, the levels of MCP-1 and IL-12p70 reflected the clinical improvements in periodontal inflammation. This suggests that the lower levels of IL-12p70 production in untreated periodontitis patients is not an intrinsic characteristic of their monocytes, but is most likely acquired by the presence of the disease.

Although the levels of MCP-1 and IL-12p70 correlated inversely, the percentage increase in IL-12p70 after therapy was 2–10 fold more than the percentage decrease in MCP-1. This may implicate that other factors could also be responsible for the suppression of IL-12p70. For example, IL-10 and PGE2 are well known inhibitors of the production of monocyte derived IL-12p70 [20,24]. It has been suggested that the suppression of IL-12p70 by MCP-1 is partly due to the production of IL-10 by the stimulated monocytes, but not PGE2 [18]. However, this was not confirmed when multiple donors were used, as there was a significant interdonor variation in this effect [18]. Above that, previous experiments with LPS-stimulated WBCC showed that there were neither differences between periodontitis patients and controls in the levels of IL-10 nor between patients before and after periodontal therapy [11](Fokkema et al. unpublished observation).

The consistently higher production of RANTES in periodontitis patients both before and after therapy, suggests an intrinsic characteristic of monocytes from these patients, and might be an important susceptibility factor for periodontitis. To date, very little is known about the possible role of RANTES in the pathogenesis of periodontitis and limited and inconclusive data are available [31–33]. Although RANTES is a potent chemokine for the selective attraction of monocytes, memory T cells, eosinophils and basophils [34–36], it is also able to activate leucocytes of the lymphoid origin [37]. RANTES may engage the T cell receptor complex, since a direct correlation between a RANTES-induced response and CD3 expression has been shown [38]. Furthermore, RANTES has been shown to up-regulate the expression of costimulatory molecules on T cells and APCs [39,40]. Therefore, it might be suggested that the high concentrations of RANTES released by APCs from periodontitis patients could additionally stimulate T cells in the periodontal lesion without the presence of antigen. This nonspecific T cell activation could be an explanation for the general belief that bacteria alone are not enough to cause destructive periodontal disease [41]. Since IL-12p70 is obligatory in directing the development of Th1 cell responses [5], and the APC derived levels of IL-12p70 were lower in untreated periodontitis patients, it may be postulated that APCs from untreated periodontitis patients have a depressed type 1- or a more type 2-inducing phenotype compared to controls. Indeed, it is generally believed that Th2 cells dominate in the periodontal lesion, whereas plasma cells are the most active secretory cells [42,43].

In conclusion, the periodontal condition affects the functional phenotype of peripheral blood monocytes by changing the release of IL-12p70 and MCP-1 levels in E. coli LPS-stimulated WBCC. In addition, the persistent elevated levels of RANTES can be regarded as an intrinsic behaviour of the peripheral blood monocytes from periodontitis patients, which might have implications for the course of the disease.

Acknowledgments

This work was supported in part by a grant of the Netherlands Institute for Dental Sciences (IOT). We thank Dr H. Braat of the Laboratory of Experimental Internal Medicine, Academic Centre of the University of Amsterdam, for providing the CC chemokine antibodies. Ir. A.A.M. Hart of the Department of Clinical Epidemiology, Academic Centre of the University of Amsterdam, is acknowledged for statistical advice. We thank C. de Slegte, W. Burger, M. Piscaer and Y. IJzerman for their clinical help. Finally, Prof Dr M. L. Kapsenberg of the Department of Cell Biology and Histology, Academic Centre of the University of Amsterdam, is kindly acknowledged for his critical comments in reading the manuscript.

References

  • 1.Gemmell E, Marshall RI, Seymour GJ. Cytokines and prostaglandins in immune homeostasis and tissue destruction in periodontal disease. Periodontol. 2000 1997;14:112–43. doi: 10.1111/j.1600-0757.1997.tb00194.x. [DOI] [PubMed] [Google Scholar]
  • 2.Page RC, Offenbacher S, Schroeder HE, Seymour GJ, Kornman KS. Advances in the pathogenesis of periodontitis: summary of developments, clinical implications and future directions. Periodontol. 2000 1997;14:216–48. doi: 10.1111/j.1600-0757.1997.tb00199.x. [DOI] [PubMed] [Google Scholar]
  • 3.Kornman KS, Page RC, Tonetti MS. The host response to the microbial challenge in periodontitis: assembling the players. Periodontol. 2000 1997;14:33–53. doi: 10.1111/j.1600-0757.1997.tb00191.x. [DOI] [PubMed] [Google Scholar]
  • 4.Banchereau J, Steinman RM. Dendritic cells and the control of immunity. Nature. 1998;392:245–52. doi: 10.1038/32588. [DOI] [PubMed] [Google Scholar]
  • 5.'Garra A. Cytokines induce the development of functionally heterogeneous T helper cell subsets. Immunity. 1998;8:275–83. doi: 10.1016/s1074-7613(00)80533-6. [DOI] [PubMed] [Google Scholar]
  • 6.Hsieh CS, Macatonia SE, Tripp CS, Wolf SF, O'Garra A, Murphy KM. Development of TH1 CD4+ T cells through IL-12 produced by Listeria-induced macrophages. Science. 1993;260:547–9. doi: 10.1126/science.8097338. [DOI] [PubMed] [Google Scholar]
  • 7.Snijdewint FG, Kalinski P, Wierenga EA, Bos JD, Kapsenberg ML. Prostaglandin E2 differentially modulates cytokine secretion profiles of human T helper lymphocytes. J Immunol. 1993;150:5321–9. [PubMed] [Google Scholar]
  • 8.van der Pouw Kraan TC, Boeije LC, Smeenk RJ, Wijdenes J, Aarden LA. Prostaglandin-E2 is a potent inhibitor of human interleukin 12 production. J Exp Med. 1995;181:775–9. doi: 10.1084/jem.181.2.775. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 9.Hilkens CM, Kalinski P, de Boer M, Kapsenberg ML. Human dendritic cells require exogenous interleukin-12-inducing factors to direct the development of naive T-helper cells toward the Th1 phenotype. Blood. 1997;90:1920–6. [PubMed] [Google Scholar]
  • 10.van den Heuvel MM, Vanhee DD, Postmus PE, Hoefsmit EC, Beelen RH. Functional and phenotypic differences of monocyte-derived dendritic cells from allergic and nonallergic patients. J Allergy Clin Immunol. 1998;101:90–5. doi: 10.1016/S0091-6749(98)70198-8. [DOI] [PubMed] [Google Scholar]
  • 11.Fokkema SJ, Loos BG, Slegte C, van der Velden U. A type 2 response in lipopolysaccharide (LPS)-stimulated whole blood cell cultures from periodontitis patients. Clin Exp Immunol. 2002;127:374–8. doi: 10.1046/j.1365-2249.2002.01753.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 12.Tokoro Y, Matsuki Y, Yamamoto T, Suzuki T, Hara K. Relevance of local Th2-type cytokine mRNA expression in immunocompetent infiltrates in inflamed gingival tissue to periodontal diseases. Clin Exp Immunol. 1997;107:166–74. doi: 10.1046/j.1365-2249.1997.d01-880.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 13.Yamazaki K, Nakajima T, Hara K. Immunohistological analysis of T cell functional subsets in chronic inflammatory periodontal disease. Clin Exp Immunol. 1995;99:384–91. doi: 10.1111/j.1365-2249.1995.tb05562.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 14.Manhart SS, Reinhardt RA, Payne JB, et al. Gingival cell IL-2 and IL-4 in early-onset periodontitis. J Periodontol. 1994;65:807–13. doi: 10.1902/jop.1994.65.9.807. [DOI] [PubMed] [Google Scholar]
  • 15.Chehimi J, Starr SE, Frank I, et al. Impaired interleukin 12 production in human immunodeficiency virus-infected patients. J Exp Med. 1994;179:1361–6. doi: 10.1084/jem.179.4.1361. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 16.van der Pouw Kraan TC, Boeije LC, de Groot ER, et al. Reduced production of IL-12 and IL-12-dependent IFN-gamma release in patients with allergic asthma. J Immunol. 1997;158:5560–5. [PubMed] [Google Scholar]
  • 17.Luther SA, Cyster JG. Chemokines as regulators of T cell differentiation. Nat Immunol. 2001;2:102–7. doi: 10.1038/84205. [DOI] [PubMed] [Google Scholar]
  • 18.Braun MC, Lahey E, Kelsall BL. Selective suppression of IL-12 production by chemoattractants. J Immunol. 2000;164:3009–17. doi: 10.4049/jimmunol.164.6.3009. [DOI] [PubMed] [Google Scholar]
  • 19.Petit MD, van Steenbergen TJ, Timmerman MF, de Graaff J, van der Velden U. Prevalence of periodontitis and suspected periodontal pathogens in families of adult periodontitis patients. J Clin Periodontol. 1994;21:76–85. doi: 10.1111/j.1600-051x.1994.tb00283.x. [DOI] [PubMed] [Google Scholar]
  • 20.Snijders A, Hilkens CM, van der Pouw Kraan TC, Engel M, Aarden LA, Kapsenberg ML. Regulation of bioactive IL-12 production in lipopolysaccharide-stimulated human monocytes is determined by the expression of the p35 subunit. J Immunol. 1996;156:1207–12. [PubMed] [Google Scholar]
  • 21.Snijders A, van der Pouw Kraan TC, Engel M, et al. Enhanced prostaglandin E2 production by monocytes in atopic dermatitis (AD) is not accompanied by enhanced production of IL-6, IL-10 or IL-12. Clin Exp Immunol. 1998;111:472–6. doi: 10.1046/j.1365-2249.1998.00516.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 22.Swaak AJ, van den Brink HG, Aarden LA. Cytokine production in whole blood cell cultures of patients with rheumatoid arthritis. Ann Rheum Dis. 1997;56:693–5. doi: 10.1136/ard.56.11.693. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 23.Shapira L, Soskolne WA, Sela MN, Offenbacher S, Barak V. The secretion of PGE2, IL-1 beta, IL-6, and TNF alpha by adherent mononuclear cells from early onset periodontitis patients. J Periodontol. 1994;65:139–46. doi: 10.1902/jop.1994.65.2.139. [DOI] [PubMed] [Google Scholar]
  • 24.van der Pouw Kraan TC, Boeije LC, Snijders A, Smeenk RJ, Wijdenes J, Aarden LA. Regulation of IL-12 production by human monocytes and the influence of prostaglandin E2. Ann N Y Acad Sci. 1996;795:147–57. doi: 10.1111/j.1749-6632.1996.tb52663.x. [DOI] [PubMed] [Google Scholar]
  • 25.Cavaillon JM, Marie C, Pitton C, Fitting C. The production of TNF alpha and IL-8 in whole blood assays are differently regulated upon activation by LPS. Prog Clin Biol Res. 1995;392:433–9. [PubMed] [Google Scholar]
  • 26.Oliver JC, Bland LA, Oettinger CW, et al. Cytokine kinetics in an in vitro whole blood model following an endotoxin challenge. Lymphokine Cytokine Res. 1993;12:115–20. [PubMed] [Google Scholar]
  • 27.Sabroe I, Jones EC, Usher LR, Whyte MK, Dower SK. Toll-like receptor (TLR) 2 and TLR4 in human peripheral blood granulocytes: a critical role for monocytes in leukocyte lipopolysaccharide responses. J Immunol. 2002;168:4701–10. doi: 10.4049/jimmunol.168.9.4701. [DOI] [PubMed] [Google Scholar]
  • 28.Haffajee AD, Cugini MA, Dibart S, Smith C, Kent RL, Jr, Socransky SS. The effect of SRP on the clinical and microbiological parameters of periodontal diseases. J Clin Periodontol. 1997;24:324–34. doi: 10.1111/j.1600-051x.1997.tb00765.x. [DOI] [PubMed] [Google Scholar]
  • 29.Karpus WJ, Kennedy KJ, Kunkel SL, Lukacs NW. Monocyte chemotactic protein 1 regulates oral tolerance induction by inhibition of T helper cell 1-related cytokines. J Exp Med. 1998;187:733–41. doi: 10.1084/jem.187.5.733. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 30.Zisman DA, Kunkel SL, Strieter RM, et al. MCP-1 protects mice in lethal endotoxemia. J Clin Invest. 1997;99:2832–6. doi: 10.1172/JCI119475. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 31.Gamonal J, Acevedo A, Bascones A, Jorge O, Silva A. Levels of interleukin-1 beta-8, and -10 and RANTES in gingival crevicular fluid and cell populations in adult periodontitis patients and the effect of periodontal treatment. J Periodontol. 2000;71:1535–45. doi: 10.1902/jop.2000.71.10.1535. [DOI] [PubMed] [Google Scholar]
  • 32.Gamonal J, Bascones A, Jorge O, Silva A. Chemokine RANTES in gingival crevicular fluid of adult patients with periodontitis. J Clin Periodontol. 2000;27:675–81. doi: 10.1034/j.1600-051x.2000.027009675.x. [DOI] [PubMed] [Google Scholar]
  • 33.Gemmell E, Carter CL, Seymour GJ. Chemokines in human periodontal disease tissues. Clin Exp Immunol. 2001;125:134–41. doi: 10.1046/j.1365-2249.2001.01511.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 34.Schall TJ, Bacon K, Toy KJ, Goeddel DV. Selective attraction of monocytes and T lymphocytes of the memory phenotype by cytokine RANTES. Nature. 1990;347:669–71. doi: 10.1038/347669a0. [DOI] [PubMed] [Google Scholar]
  • 35.Kameyoshi Y, Dorschner A, Mallet AI, Christophers E, Schroder JM. Cytokine RANTES released by thrombin-stimulated platelets is a potent attractant for human eosinophils. J Exp Med. 1992;176:587–92. doi: 10.1084/jem.176.2.587. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 36.Conti P, Reale M, Barbacane RC, et al. Massive infiltration of basophilic cells in inflamed tissue after injection of RANTES. Immunol Lett. 1997;58:101–6. doi: 10.1016/s0165-2478(97)00034-5. [DOI] [PubMed] [Google Scholar]
  • 37.Bacon KB, Premack BA, Gardner P, Schall TJ. Activation of dual T cell signaling pathways by the chemokine RANTES. Science. 1995;269:1727–30. doi: 10.1126/science.7569902. [DOI] [PubMed] [Google Scholar]
  • 38.Dairaghi DJ, Soo KS, Oldham ER, et al. RANTES-induced T cell activation correlates with CD3 expression. J Immunol. 1998;160:426–33. [PubMed] [Google Scholar]
  • 39.Taub DD, Ortaldo JR, Turcovski-Corrales SM, Key ML, Longo DL, Murphy WJ. Beta chemokines costimulate lymphocyte cytolysis, proliferation, and lymphokine production. J Leukoc Biol. 1996;59:81–9. doi: 10.1002/jlb.59.1.81. [DOI] [PubMed] [Google Scholar]
  • 40.Lillard JW, Jr, Boyaka PN, Taub DD, McGhee JR. RANTES potentiates antigen-specific mucosal immune responses. J Immunol. 2001;166:162–9. doi: 10.4049/jimmunol.166.1.162. [DOI] [PubMed] [Google Scholar]
  • 41.Page RC, Kornman KS. The pathogenesis of human periodontitis: an introduction. Periodontol. 2000 1997;14:9–11. doi: 10.1111/j.1600-0757.1997.tb00189.x. [DOI] [PubMed] [Google Scholar]
  • 42.Gemmell E, Yamazaki K, Seymour G. J. Destructive periodontitis lesions are determined by the nature of the lymphocytic response. Crit Rev Oral Biol Med. 2002;13:17–34. doi: 10.1177/154411130201300104. [DOI] [PubMed] [Google Scholar]
  • 43.Kinane DF, Lappin DF. Clinical, pathological and immunological aspects of periodontal disease. Acta Odontol Scand. 2001;59:154–60. doi: 10.1080/000163501750266747. [DOI] [PubMed] [Google Scholar]

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