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. 1998 Oct;66(10):4942–4946. doi: 10.1128/iai.66.10.4942-4946.1998

Interleukin-12 Has a Role in Mediating Resistance of Murine Strains to Tyzzer’s Disease

Roger A Van Andel 1,†, Reuel R Hook Jr 1, Craig L Franklin 1, Cynthia L Besch-Williford 1, Lela K Riley 1,*
Editor: J R McGhee1
PMCID: PMC108611  PMID: 9746600

Abstract

Clostridium piliforme induces enterohepatic disease in many domestic and laboratory animal species. Susceptibility to infection is known to vary with the immune status and strain of the host, but little is known about specific immune mechanisms that regulate this disease. To evaluate host control of C. piliforme infection, we examined the role of interleukin-12 (IL-12) both in the control of and in the response to murine C. piliforme infection. For this study, 3-week-old C. piliforme-resistant C57BL/6 or -susceptible DBA/2 mice were infected intravenously with either the toxic H1 or the nontoxic M1 C. piliforme isolate. Serum and liver samples were collected prior to C. piliforme inoculation (day 0) and at days 1, 3, 7, 14, and 28 postinoculation. Evaluation of hepatic IL-12 p40 mRNA expression by reverse transcription-PCR and of total-IL-12 protein levels in serum by enzyme-linked immunosorbent assay revealed that C. piliforme induced elevations in both hepatic p40 mRNA and serum total-IL-12 levels at all times postinoculation. Elevations were similar with both toxic and nontoxic C. piliforme isolates. Levels of total IL-12 in serum were significantly (P < 0.05) higher in C57BL/6 mice than in DBA/2 mice. Additional experiments were performed in which polyclonal antibody treatment was used to neutralize IL-12 in mice of both strains prior to intravenous inoculation with toxic C. piliforme H1. IL-12 neutralization increased the severity of Tyzzer’s disease at day 3 postinoculation in both mouse strains, but the degree of increase was greater in C57BL/6 mice than in DBA/2 mice.

Clostridium piliforme is the agent of Tyzzer’s disease. Although C. piliforme is classified as a Clostridium sp. based upon 16S rRNA analysis, it is unlike other clostridia in several respects. The organism is an obligately intracellular pathogen, consistently stains gram negative, and is positive for lipopolysaccharide by the Limulus amebocyte lysate assay (34). In many animal species, C. piliforme infections induce rapidly fatal enterohepatic disease (26, 35, 37, 38, 42), and the bacterium has recently been reported as a cause of subcutaneous infection in immunocompromised humans (14, 31). However, infections in mice are most often subclinical (26). Factors which mediate host resistance to clinical C. piliforme are not well defined but apparently involve both bacterial and host factors (8, 19, 30, 33, 36).

Bacterial factors that influence disease severity are not well characterized but may include recently described toxins (30). Previous studies in our laboratory have documented that the severity of experimental murine C. piliforme infection varies with the toxicity of the bacterial isolate (34). Toxic isolates induce pronounced hepatic lesions with histologically discernible bacteria up to 14 days postinoculation, whereas nontoxic isolates rarely induce lesions or histologically visible bacteria (34).

Several clinical and experimental findings suggest that the host immune system may also regulate C. piliforme expression. For example, susceptibility to Tyzzer’s disease varies with the host’s strain, age, and immune status; the severity of the disease is greatest in weanling and immunocompromised animals (19, 37). Although murine C. piliforme infection is often subclinical, mouse strains differ in susceptibility to disease (9, 12, 33, 37). DBA/2 mice are susceptible to C. piliforme infection and typically develop multifocal hepatic necrosis following natural or experimental infection. Conversely, C57BL/6 mice develop only a few small hepatic lesions following exposure to C. piliforme and are considered resistant.

Previous investigators have indicated that murine susceptibility to C. piliforme may be mediated by leukocytes such as B and T lymphocytes and natural killer (NK) cells (19, 33, 36). One of the most important cytokines regulating lymphocyte and NK cell activity is interleukin-12 (IL-12), a heterodimeric 70-kDa protein, which was originally named NK cell stimulatory factor. IL-12 promotes development of the Th1-type response by T lymphocytes and NK cells and is known to mediate resistance to pathogens such as Brucella abortus, Chlamydia trachomatis, Listeria monocytogenes, Candida albicans, Mycobacterium tuberculosis, and Salmonella spp. (3–5, 16, 20, 39, 43). Given the apparent importance of lymphocytes and NK cells in mediating the susceptibility of murine strains to C. piliforme infection (19, 33, 38), this study was undertaken to investigate the role of IL-12 in Tyzzer’s disease.

In this study, we examined the IL-12 response to both a toxic (H1) and a nontoxic (M1) C. piliforme isolate in susceptible DBA/2 and resistant C57BL/6 mice. Results of these studies demonstrated that hepatic IL-12 mRNA levels were upregulated and serum IL-12 levels were elevated for at least 28 days by both C. piliforme isolates. Serum IL-12 levels were significantly (P < 0.05) higher in C57BL/6 mice than in DBA/2 mice.

To further evaluate the role of IL-12 in Tyzzer’s disease, polyclonal anti-IL-12 antibodies were used to neutralize IL-12 in both mouse strains prior to C. piliforme H1 challenge. While IL-12 neutralization increased the severity of disease in both mouse strains, the increase was significantly (P < 0.05) greater in C57BL/6 mice than in DBA/2 mice. These data document the importance of IL-12 in the murine immune response to C. piliforme challenge and suggest a possible role for IL-12 in mediating the susceptibility of murine strains to infection.

MATERIALS AND METHODS

Mice.

Female DBA/2 and C57BL/6 mice were obtained at 3 weeks of age from Charles River Laboratories (Wilmington, Mass.). Mice were allowed to acclimate for 3 days prior to use.

Bacteria.

The toxic H1 isolate of C. piliforme, which induces experimental liver lesions in mice, was isolated from the livers of hamsters with clinical Tyzzer’s disease (30). The nontoxic M1 isolate of C. piliforme, which does not induce experimental liver lesions in mice, was isolated from the livers of subclinically infected mice (30). Both isolates were subsequently maintained in tissue culture (30). For animal inoculation, bacteria were grown on murine liver cells (BNL cell line; ATCC TIB 73) and processed as previously described (33).

Plaque assay.

To determine the infectivity of bacteria from tissue culture, plaque assays were performed (17, 33, 40). Plaque assay results indicated 25 to 35% viability among C. piliforme preparations.

Experimental design.

Groups of 10 or more DBA/2 mice and 10 or more C57BL/6 mice were inoculated intravenously with 105 C. piliforme H1 or M1 organisms and compared to control animals inoculated intravenously with BNL cells in order to evaluate the in vivo IL-12 response to Tyzzer’s disease. Hepatic and blood samples were collected prior to inoculation (day 0) and at days 1, 3, 7, 14, and 28 post-bacterial inoculation. Hepatic samples were snap frozen in liquid nitrogen and stored at −80°C until they were evaluated for IL-12 mRNA production by reverse transcription-PCR (RT-PCR), as described below. Blood samples from at least two (time 0) or four (all other time points) groups of five animals at each time point were pooled, allowed to clot at room temperature, centrifuged at 5,000 × g for serum collection, and stored at −20°C until they were evaluated for IL-12 by enzyme-linked immunosorbent assay (ELISA) as described below.

Mice were treated with polyclonal anti-IL-12 antibody for evaluation of the effect of IL-12 neutralization on acute murine Tyzzer’s disease. Neutralizing sheep polyclonal anti-murine IL-12 (a kind gift from V. Van Cleave, Genetics Institute, Cambridge, Mass.) was administered intraperitoneally at a dose of 200 μg/mouse (concentration based on absorbance at 280 nm as determined by the Genetics Institute) at 24 h prior to infection and again 2 days later, as previously described (12). Nonspecific sheep immunoglobulin G (IgG) was administered intraperitoneally to control mice at the same time points. Mice were inoculated with C. piliforme H1 24 h after the initial antibody or nonspecific IgG treatment. Previous studies documented that the C. piliforme H1 isolate induced hepatic lesions which were most severe at day 3 post-bacterial inoculation (33). Thus, serum and hepatic samples were obtained at day 3 postinoculation in order to evaluate the effect of anti-IL-12 antibody on murine Tyzzer’s disease. Depletion of serum IL-12 levels was documented by a cytokine-specific ELISA as described below.

Reverse transcription for preparation of cDNA.

Hepatic tissues collected at necropsy were processed for mRNA isolation as previously described (16). Briefly, 10 to 50 mg of hepatic tissue was pulverized under liquid nitrogen and resuspended in Ultraspec solution (Biotecx Corp., Houston, Tex.), and RNA was extracted with chloroform. RNA concentration and purity were determined spectrophotometrically by using 260 and 280 nm readings. Reverse transcription was performed with 1 μg of total RNA by using oligo(dT) primers (Superscript II Reverse Transcription kit; Gibco BRL Corp., Gaithersburg, Md.) according to the manufacturer’s instructions.

Cytokine-specific PCR.

Cytokine-specific PCR was performed with 1 μg of cDNA by using primers specific for murine β-actin or IL-12 p40. Primers for β-actin were synthesized by Integrated DNA Technologies (Coralville, Iowa) by using previously described sequences (2, 27). Primers for IL-12 p40 were synthesized with sequences kindly provided by Steven Kunkel (University of Michigan). The sequences for cytokine primers were as follows: for β-actin, 5′-GTGGGCCGCTCTAGGCACCAAGGT-3′ and 5′-CTGGATGGCTACGTACATGGC-3′, and for IL-12 p40, 5′-CTCACCTGTGACACGCCTGA-3′ and 5′-CAGGACACTGAATACTTCTC-3′. Briefly, samples were amplified with Perkin-Elmer reagents and Taq polymerase in 50 μl of PCR solution in thin-walled reaction vials. Samples were denatured at 94°C for 2 min, followed by 35 cycles of 94°C for 30 s, 58°C for 45 s, and 72°C for 2 min. A 7-min final extension was performed at 72°C.

Cytokine ELISA.

Serum samples collected at necropsy were quantitatively assayed for total-IL-12 levels by using a commercially available ELISA kit (Genzyme Corp., Cambridge, Mass.) according to the manufacturer’s instructions. Briefly, 50 μl of pooled sera was diluted in 50 μl of buffer and loaded into commercially prepared antibody-coated 96-well plates. Serum cytokine levels were determined by comparing the intensity of the ELISA signal to standards of known concentrations of IL-12. Each pooled sample was run at least in duplicate.

Tissue harvest for evaluation of lesions and bacterial loads.

Hepatic lesions and bacterial loads were evaluated at day 3 postinoculation as previously described (33). Briefly, gross hepatic surface lesions were scored on a scale of 0 to 10 as follows: 0, no hepatic lesions; 1, 1 to 10 lesions per liver; 2, 11 to 20 lesions, etc. Livers with >90 lesions were given a score of 10. Histologic lesions were evaluated by using 5-μm-thick sections stained with hematoxylin and eosin and were assigned cumulative scores from 35 high-power fields (400×). Histologic lesions were scored on a scale from 0 to 10 as follows: 0, no lesions; 2, 1 to 3 coagulative necrotic lesions per liver; 4, 4 to 6 lesions; 6, 7 to 10 lesions; 8, >10 lesions; 10, >10 lesions more than half of which had caseous necrosis. Attempts in our laboratory to quantitate C. piliforme from infected-liver homogenates by plaque assays have been unsuccessful; however, the large size of C. piliforme (10 to 40 μm in length) allows visualization of individual bacteria within hepatocytes. Therefore, bacterial load was assessed by counting the number of organisms in 35 high-power silver-stained hepatic fields by using the following scale: 0, no bacteria; 2, 1 to 50 bacteria; 4, 51 to 100 bacteria; 6, 101 to 500 bacteria; 8, 501 to 1,000 bacteria; 10, >1,000 bacteria.

Statistical analysis.

Data were evaluated for normal distribution by the Kolmogorav-Smirov test. When normally distributed, data were analyzed by one-way analysis of variance. When data were not normally distributed, analysis was performed by analysis of variance of Wilcox ranks. All analyses were performed with SigmaStat (SSPS Corp., San Diego, Calif.) software. Results are reported as means ± standard errors of the means. P values of <0.05 were considered significant.

RESULTS

Effect of C. piliforme challenge on hepatic IL-12 p40 mRNA expression.

IL-12 is a heterodimeric protein (p70) composed of p40 and p35 subunits. Both subunits may be constitutively expressed, but exposure to foreign antigens reportedly induces greater alterations in p40 mRNA expression than in p35 mRNA expression (28). DBA/2 and C57BL/6 mice were injected intravenously with 105 organisms of either the toxic H1 or the nontoxic M1 C. piliforme isolate in order to evaluate whether C. piliforme induces hepatic expression of IL-12 p40 and whether this expression differs between strains of mice or between mice inoculated with different bacterial isolates. Hepatic IL-12 p40 mRNA was not detectable in uninoculated mice or in mice inoculated intravenously with uninfected BNL cells (Fig. 1 and 2). Hepatic IL-12 p40 mRNA expression could be demonstrated at all time points after C. piliforme challenge. The cytotoxic H1 isolate induced a higher level of IL-12 p40 mRNA expression than did the nontoxigenic M1 isolate.

FIG. 1.

FIG. 1

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Results of RT-PCR for hepatic IL-12 p40 (A) and β-actin (B) in C57BL/6 mice at days 0, 1, 3, 7, 14, and 28 post-C. piliforme H1 or M1 inoculation and at day 3 post-BNL cell inoculation in control animals. M, molecular weight marker; B, hepatic samples from BNL-inoculated control mice 3 days postinoculation. No cytokine induction was seen at any time in BNL-inoculated control mice. Similar results were obtained from five mice at each time point.

FIG. 2.

FIG. 2

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Results of RT-PCR for hepatic IL-12 p40 (A) and β-actin (B) in DBA/2 mice at days 0, 1, 3, 7, 14, and 28 post-C. piliforme H1 or M1 inoculation and at day 3 post-BNL cell inoculation in control animals. No cytokine induction was seen at any time in BNL-inoculated control mice. Similar results were obtained from five mice at each time point.

Effect of C. piliforme challenge on serum IL-12 levels.

Serum samples were collected from mice at necropsy to determine whether hepatic IL-12 p40 mRNA expression was related to a systemic increase in total-IL-12 levels in serum. Examination of serum samples by ELISA demonstrated that levels of total (p40 and p70) IL-12 in uninoculated animals were similar to those previously reported for uninfected mice (10) and were consistent with levels reported by the distributor of the ELISA (11). Inoculation of mice with BNL cells did not alter serum IL-12 levels (Fig. 3). However, significant (P < 0.05) elevations in serum total-IL-12 levels were seen by day 1 postinoculation in both mouse strains inoculated with either C. piliforme isolate. Serum total-IL-12 levels were significantly (P < 0.05) higher in C57BL/6 mice than in DBA/2 mice at all times post-H1 inoculation and by day 3 post-M1 inoculation.

FIG. 3.

FIG. 3

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Production of IL-12 following infection of C57BL/6 (C57) and DBA/2 (DBA) mice with either the H1 (A) or the M1 (B) isolate of C. piliforme (means ± standard errors of the means). Serum samples taken from these mice at days 0, 1, 3, 7, 14, and 28 postinoculation and from control (BNL cell-inoculated) mice were evaluated by a cytokine-specific ELISA as described in Materials and Methods. Pooled sera from at least two (time 0) or four (all other time points) groups of five animals were run in duplicate for each time point.

Effect of IL-12 depletion on the course of in vivo C. piliforme infection.

Mice were treated with a polyclonal antibody for IL-12 neutralization and were then inoculated with 105 C. piliforme H1 organisms in order to evaluate whether endogenous IL-12 regulates the response to C. piliforme infection. Anti-IL-12 treatment resulted in serum IL-12 levels which were undetectable in both strains of mice and induced significant (P < 0.05) increases in hepatic-lesion and bacterial-load scores compared to scores for control mice (Fig. 4). At day 3 postinoculation, the magnitudes of the increases in lesion and bacterial-load scores were significantly (P < 0.05) greater in C57BL/6 mice than in DBA/2 mice. In IL-12-depleted C57BL/6 mice, gross and histologic lesion scores increased 4.5- and 6.4-fold, respectively, and bacterial-load scores increased 5.6-fold. IL-12 depletion in DBA/2 mice resulted in gross and histologic lesion score increases of 2.4- and 1.8-fold, respectively, while bacterial-load scores increased 3.2-fold.

FIG. 4.

FIG. 4

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Gross hepatic surface lesion scores, histologic lesion scores, and bacterial-load scores in weanling DBA/2 mice treated with anti-IL-12 (n = 16) or IgG (control group; n = 12) (A) and in weanling C57BL/6 mice treated with anti-IL-12 (n = 15) or IgG (control group; n = 14) (B).

DISCUSSION

In this study we used an approach similar to that reported by others, in which RT-PCR data were used to qualitatively demonstrate mRNA upregulation while ELISA data were used to quantitate the IL-12 response to C. piliforme (7, 13, 20, 21). These studies demonstrated that C. piliforme induced hepatic IL-12 p40 mRNA expression and increased levels of total IL-12 in serum. Consistent with previous reports by other investigators (13), tissue expression of IL-12 p40 mRNA was not detected preinoculation, in spite of the fact that total IL-12 was detectable in serum. Alterations in hepatic p40 mRNA and total IL-12 were apparent from day 1 postinoculation until day 28 postinoculation, the last point evaluated. Total-IL-12 levels after inoculation with C. piliforme were significantly (P < 0.05) higher in C57BL/6 mice than in DBA/2 mice. Previous investigators have reported that results of ELISAs which detect IL-12 p40 alone or total IL-12 demonstrate close correlations with those of IL-12 bioassays (1, 23). In this study, IL-12 neutralization increased lesion and bacterial-load scores in both strains of mice, but these increases were larger in C57BL/6 mice than in DBA/2 mice. IL-12-depleted C57BL/6 mice developed gross and histologic hepatic lesions and bacterial loads comparable to those typically seen in DBA/2 mice. These data suggest that IL-12 may regulate the susceptibility of murine strains to C. piliforme infection.

It is interesting that the intensities of the serum total-IL-12 response did not differ significantly (P > 0.05) between mice inoculated with the toxic C. piliforme isolate and those inoculated with the nontoxic isolate. Although recent data from our laboratory indicate that both isolates colonize the liver and persist for up to 28 days postinoculation (34), the M1 isolate produces no discernible hepatic lesions or leukocytic influx. In contrast, inoculation of mice with the H1 isolate produces dramatic hepatic lesions and leukocytic responses. Thus, one might have expected higher total-IL-12 levels in H1-infected mice than in M1-infected mice. However, induction of similar total-IL-12 levels by pathogens which differ in virulence is not without precedent. Previous investigators have suggested that with bacteria such as Listeria spp. and M. tuberculosis, levels of total-IL-12 induction may be similar for isolates that differ in virulence or even viability (10, 41). Other investigations have shown that phagocytosis of latex beads by macrophages may induce total-IL-12 levels as high as those seen with viable M. tuberculosis (18). The conclusion from these studies is that phagocytosis itself maybe sufficient to induce macrophage expression of total IL-12 (10, 18).

IL-12 regulates host response to many facultatively and obligately intracellular pathogens, including Coccidioides immitis, L. monocytogenes, Mycobacterium avium, Salmonella spp., Toxoplasma gondii, and B. abortus (4, 5, 15, 22, 24, 32, 43). IL-12 is an important regulator of NK cell activity, and most studies which have demonstrated a role for IL-12 in the murine response to these pathogens also implicate upregulation of NK cells in the control of infection (22, 24, 43). Previous studies in our laboratory documented that NK cells are important in C. piliforme infection and probably play a role in determining the resistance of certain mouse strains to Tyzzer’s disease (33). The resistance of C57BL/6 mice and the susceptibility of DBA/2 mice to C. piliforme infection are consistent with this hypothesis, since the NK cell cytotoxic activity of C57BL/6 mice is higher than that of DBA/2 mice, whose NK cell activity is low compared to that in most mouse strains (29). However, NK cell cytotoxic activity does not fully explain the resistance of murine strains to C. piliforme. C57BL/6 mice are one of the most C. piliforme-resistant mouse strains (37); however, their NK cell cytotoxic activity is intermediate among mouse strains (29). C3H mice are relatively susceptible to C. piliforme infection (37), yet their NK cell cytotoxic activity is higher than that in most mouse strains, including C57BL/6 mice. Thus, there is clearly more involved in IL-12-mediated C. piliforme resistance than NK cell activity alone, and the role of IL-12 is likely mediated through several cell types and cytokine responses.

In conclusion, we have shown that C. piliforme inoculation induces prolonged IL-12 upregulation in both C57BL/6 and DBA/2 mice. IL-12 levels remained elevated 28 days postinoculation, regardless of bacterial toxicity or the development of hepatic lesions. The C. piliforme-induced IL-12 response was significantly higher in C57BL/6 mice than in DBA/2 mice, and neutralization of IL-12 resulted in comparable lesion and bacterial-load scores in C57BL/6 mice and non-IL-12-neutralized DBA/2 mice. Based on these findings, it appears that IL-12 is involved in mediating the resistance of murine strains to Tyzzer’s disease. These studies also indicate that subclinical C. piliforme infection may have a prolonged impact on IL-12 levels in the host. Such cytokine perturbations have the potential to significantly alter physiologic responses in subsequent research uses of mice. For example, investigators have documented that subclinical infections with pathogens such as L. monocytogenes (6) and C. albicans (20) may prolong host survival and alter immune responses of mice to subsequent experimental infections or transplanted tumors (25). On the basis of this study, it appears that subclinical murine C. piliforme infections may have a significant impact on research mice and on investigations which utilize infected animals, regardless of whether any gross or histologic evidence of infection is ever seen.

ACKNOWLEDGMENTS

We thank Howard Wilson for technical and computer assistance in the preparation of the manuscript.

This work was supported in part by Public Health Service grant 5F32-RR05057 from the National Institutes of Health.

REFERENCES

  • 1.Aliberti J C S, Cardoso M A G, Martins G A, Gazzinelli R T, Vieira L Q, Silva J S. Interleukin-12 mediates resistance to Trypanosoma cruzi in mice and is produced by murine macrophages in response to live trypomastigotes. Infect Immun. 1996;64:1961–1967. doi: 10.1128/iai.64.6.1961-1967.1996. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 2.Alonso S, Minty A, Bourlet Y, Buckingham M. Comparison of three actin-coding sequences in the mouse; evolutionary relationships between the actin genes of warm-blooded vertebrates. J Mol Evol. 1986;23:11–22. doi: 10.1007/BF02100994. [DOI] [PubMed] [Google Scholar]
  • 3.Cain T K, Rank R G. Local Th1-like responses are induced by intravaginal infection of mice with the mouse pneumonitis biovar of Chlamydia trochomatis. Infect Immun. 1995;63:1784–1789. doi: 10.1128/iai.63.5.1784-1789.1995. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 4.Chong C, Bost K L, Clements J D. Differential production of interleukin-12 mRNA by murine macrophages in response to viable or killed Salmonella spp. Infect Immun. 1996;64:1154–1160. doi: 10.1128/iai.64.4.1154-1160.1996. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 5.Cooper A M, Roberts A D, Rhoades E R, Callahan J E, Getzy D M, Orme I M. The role of interleukin-12 in acquired immunity to Mycobacterium tuberculosis infection. Immunology. 1995;84:423–432. [PMC free article] [PubMed] [Google Scholar]
  • 6.Ehlers S, Mielke M E A, Blankenstein T, Hahn H. Kinetic analysis of cytokine gene expression in the livers of naïve and immune mice infected with Listeria monocytogenes. The immediate early phase in innate resistance and acquired immunity. J Immunol. 1992;149:3016–3022. [PubMed] [Google Scholar]
  • 7.Faulkner C B, Simecka J W, Davidson M K, Davis J K, Schoeb T R, Lindsey J R, Everson M P. Gene expression and production of tumor necrosis factor alpha, interleukin 1, interleukin 6, and gamma interferon in C3H/HeN and C57BL/6N mice in acute Mycoplasma pulmonis disease. Infect Immun. 1995;63:4084–4090. doi: 10.1128/iai.63.10.4084-4090.1995. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 8.Fries A S. Studies on Tyzzer’s disease: acquired immunity against infection and activation of infection by immunosuppressive treatment. Lab Anim. 1979;13:143–147. doi: 10.1258/002367779780943486. [DOI] [PubMed] [Google Scholar]
  • 9.Fries A S. Antibodies to Bacillus piliformis (Tyzzer’s disease) in sera from man and other species. In: Spiegel A, Erichsen S, Utrecht H A, editors. Animal quality and models in biomedicala research: 7th ICLAS Symposium. New York, N.Y: Gustav Fischer Verlag; 1980. pp. 245–252. [Google Scholar]
  • 10.Fulton S A, Johnsen J M, Wolf S F, Sieburth D S, Boom W H. Interleukin-12 production by human monocytes infected with Mycobacterium tuberculosis: role of phagocytosis. Infect Immun. 1996;64:2523–2531. doi: 10.1128/iai.64.7.2523-2531.1996. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 11.Genzyme Technical Service. Personal communication.
  • 12.Gibson S V, Waggie K S, Wagner J E, Ganaway J R. Diagnosis of subclinical Bacillus piliformis infection in a barrier-maintained mouse production colony. Lab Anim Sci. 1987;37:786–788. [PubMed] [Google Scholar]
  • 13.Heinzel F P, Rerko R M, Ling P, Hakimi J, Schoenhaut D S. Interleukin 12 is produced in vivo during endotoxemia and stimulates synthesis of gamma interferon. Infect Immun. 1994;62:4244–4249. doi: 10.1128/iai.62.10.4244-4249.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 14.Hilyard, E. J., T. L. Hadfield, M. E. D’Nicuola, K. Smith, and H. G. Skelton. Detection of Tyzzer’s bacillus in humans from paraffin-embedded tissue using polymerase chain reaction, abstr. C-402, p. 72. In Abstracts of the 96th General Meeting of the American Society for Microbiology 1996. American Society for Microbiology, Washington, D.C.
  • 15.Hunter C A, Candolfi E, Subauste C, Van Cleave V, Remington J S. Studies on the role of interleukin-12 in acute murine toxoplasmosis. Immunology. 1995;84:16–20. [PMC free article] [PubMed] [Google Scholar]
  • 16.Iizawa Y, Wagner R D, Czuprynski C J. Analysis of cytokine mRNA expression in Listeria-resistant C57BL/6 and Listeria-susceptible A/J mice during Listeria monocytogenes infection. Infect Immun. 1993;61:3739–3744. doi: 10.1128/iai.61.9.3739-3744.1993. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 17.Kawamura S, Taguchi F, Fujiwara K. Plaque formation by Tyzzer’s organism in primary monolayer culture of mouse hepatocytes. Microbiol Immunol. 1983;27:415–424. doi: 10.1111/j.1348-0421.1983.tb00600.x. [DOI] [PubMed] [Google Scholar]
  • 18.Ladel C, Szalay G, Riedel D, Kaufmann S H E. Interleukin-12 secretion by Mycobacterium tuberculosis-infected macrophages. Infect Immun. 1997;65:1936–1938. doi: 10.1128/iai.65.5.1936-1938.1997. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 19.Livingston R S, Franklin C L, Besch-Williford C L, Hook R R, Jr, Riley L K. A novel presentation of Clostridium piliforme infection (Tyzzer’s disease) in nude mice. Lab Anim Sci. 1996;46:21–25. [PubMed] [Google Scholar]
  • 20.Louie A, Baltch A L, Smith R P, Frankle M A, Ritz W J, Singh J K, Gordon M A. Tumor necrosis factor alpha has a protective role in a murine model of systemic candidiasis. Infect Immun. 1994;62:2761–2772. doi: 10.1128/iai.62.7.2761-2772.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 21.Lukacs N W, Strieter R M, Chensue S W, Widmer M, Kunkel S L. TNF-alpha mediates recruitment of neutrophils and eosinophils during airway inflammation. J Immunol. 1995;154:5411–5417. [PubMed] [Google Scholar]
  • 22.Magee D M, Cox R A. Interleukin-12 regulation of host defenses against Coccidioides immitis. Infect Immun. 1996;64:3609–3613. doi: 10.1128/iai.64.9.3609-3613.1996. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 23.Mahon B P, Ryan M S, Griffin F, Mills K H G. Interleukin-12 is produced by macrophages in response to live or killed Bordetella pertussis and enhances the efficacy of an acellular pertussis vaccine by promoting induction of Th1 cells. Infect Immun. 1996;64:5295–5301. doi: 10.1128/iai.64.12.5295-5301.1996. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 24.Mastroeni P, Harrison J A, Chabalgoity J A, Hormaeche C E. Effect of interleukin 12 neutralization on host resistance and gamma interferon production in mouse typhoid. Infect Immun. 1996;64:189–196. doi: 10.1128/iai.64.1.189-196.1996. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 25.Molloy R G, Mannick J A, Rodrick M L. Cytokines, sepsis, and immunomodulation. Br J Surg. 1993;80:289–297. doi: 10.1002/bjs.1800800308. [DOI] [PubMed] [Google Scholar]
  • 26.Motzel S L, Riley L K. Bacillus piliformis flagellar antigens for serodiagnosis of Tyzzer’s disease. J Clin Microbiol. 1991;29:2566–2570. doi: 10.1128/jcm.29.11.2566-2570.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 27.Novakovic S, Buldogh I. In vitro TNF-α production and in vivo alteration of TNF-α RNA in mouse peritoneal macrophages after treatment with different bacterial derived agents. Cancer Lett. 1989;81:99–109. doi: 10.1016/0304-3835(94)90171-6. [DOI] [PubMed] [Google Scholar]
  • 28.Oswald I P, Dozois C M, Petit J F, Lemaire G. Interleukin-12 synthesis is a required step in trehalose dimycolate-induced activation of mouse peritoneal macrophages. Infect Immun. 1997;65:1364–1369. doi: 10.1128/iai.65.4.1364-1369.1997. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 29.Pope B L, Chourmouzis E, Sigindere J, MacIntyre J P, Capetola R J, Lau C Y. In vivo activation of natural killer cells and priming of IL-2 responsive cytolytic cells by loxoribine (7-allyl-8-oxoguanosine) Cell Immunol. 1993;147:302–312. doi: 10.1006/cimm.1993.1071. [DOI] [PubMed] [Google Scholar]
  • 30.Riley L K, Caffrey C J, Musille V S, Meyer J K. Toxicity of Bacillus piliformis. J Med Microbiol. 1992;37:77–80. doi: 10.1099/00222615-37-1-77. [DOI] [PubMed] [Google Scholar]
  • 31.Smith K J, Skelton H G, Hilyard E J, Hadfield T, Moeller R S, Turr S, Decker C. Bacillus piliformis infection (Tyzzer’s disease) in a patient infected with HIV-1: confirmation with 16S ribosomal RNA sequence analysis. J Am Acad Dermatol. 1996;34:343–348. doi: 10.1016/s0190-9622(07)80005-3. [DOI] [PubMed] [Google Scholar]
  • 32.Tripp C S, Gately M K, Hakimi J, Ling P, Unanue E R. Neutralization of IL-12 decreases resistance to Listeria in SCID and C.B.-17 mice. J Immunol. 1994;152:1883–1887. [PubMed] [Google Scholar]
  • 33.Van Andel R A, Hook R R, Jr, Franklin C L, Besch-Williford C L, van Rooijen N, Riley L K. Effects of neutrophil, natural killer cell, and macrophage depletion on murine Clostridium piliforme infection. Infect Immun. 1997;65:2725–2731. doi: 10.1128/iai.65.7.2725-2731.1997. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 34.Van Andel, R. A., C. L. Franklin, C. L. Besch-Williford, R. R. Hook, Jr., and L. K. Riley. Unpublished data.
  • 35.Veazey R S, Paulsen D B, Schaeffer D O. Encephalitis in gerbils due to naturally occurring infection with Bacillus piliformis (Tyzzer’s disease) Lab Anim Sci. 1992;42:516–518. [PubMed] [Google Scholar]
  • 36.Waggie K S, Ganaway J R, Wagner J E, Spencer T H. Experimentally induced Tyzzer’s disease in Mongolian gerbils (Meriones unguiculatus) Lab Anim Sci. 1984;34:53–57. [PubMed] [Google Scholar]
  • 37.Waggie K S, Hansen C T, Ganaway J R, Spencer T H. A study of mouse strain susceptibility to Bacillus piliformis (Tyzzer’s disease): the association of B-cell function and resistance. Lab Anim Sci. 1981;31:139–142. [PubMed] [Google Scholar]
  • 38.Waggie K S, Thornburg L P, Grove K J, Wagner J E. Lesions of experimentally induced Tyzzer’s disease in Syrian hamsters, guinea pigs, mice, and rats. Lab Anim. 1987;21:155–160. doi: 10.1177/002367728702100213. [DOI] [PubMed] [Google Scholar]
  • 39.Wagner R D, Czuprynski C J. Cytokine mRNA expression in livers of mice infected with Listeria monocytogenes. J Leukoc Biol. 1993;53:525–531. doi: 10.1002/jlb.53.5.525. [DOI] [PubMed] [Google Scholar]
  • 40.Wike D A, Tallent G, Peacock M G, Ormsbee R A. Studies of the rickettsial plaque assay technique. Infect Immun. 1972;5:715–722. doi: 10.1128/iai.5.5.715-722.1972. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 41.Xiong H, Kawamura I, Nishibori T, Mitsuyama M. Cytokine gene expression in mice at an early stage of infection with various strains of Listeria spp. differing in virulence. Infect Immun. 1994;62:3649–3654. doi: 10.1128/iai.62.9.3649-3654.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 42.Young J K, Baker D C, Burney D P. Naturally occurring Tyzzer’s disease in a puppy. Vet Pathol. 1995;32:63–65. doi: 10.1177/030098589503200110. [DOI] [PubMed] [Google Scholar]
  • 43.Zhan Y, Kelso A, Cheers C. Cytokine production in the murine response to brucella infection or immunization with antigenic extracts. Immunology. 1993;80:458–464. [PMC free article] [PubMed] [Google Scholar]

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