Skip to main content
PMC home page
The British Journal of Ophthalmology logoLink to The British Journal of Ophthalmology
. 1997 May;81(5):396–401. doi: 10.1136/bjo.81.5.396

Macrophages and MHC class II positive cells in the choroid during endotoxin induced uveitis

P Yang 1, A F de Vos 1, A Kijlstra 1
PMCID: PMC1722201  PMID: 9227206

Abstract

AIMS/BACKGROUND—Endotoxin induced uveitis has been regarded as a model for acute anterior uveitis and until now little was known about choroidal involvement. The aim of this study was to investigate changes in macrophages and MHC class II positive cells in the choroid of Lewis rats during endotoxin induced uveitis.
METHODS—Choroid-sclera wholemounts were isolated from normal Lewis rats and at different time points—4, 8, 16, 24, 48, 72, and 96 hours, and 7, 10, and 14 days after a footpad injection of 200 µg of lipopolysaccharide (LPS). Immunohistochemistry was performed using the monoclonal antibodies ED1 (monocytes, macrophages, dendritic cells), and OX6 (MHC class II antigen).
RESULTS—In normal rats, two layers of macrophages were identified in the choroid; a layer located immediately beneath the retinal pigment epithelium (RPE) and a layer bordering the sclera. The density of ED1 positive cells in the layer bordering the RPE cells was 902 (SD 132) cells/mm2 whereas the scleral layer had a cell density of 389 (73) cells/mm2. Based on morphology, positive cells could be divided into two main categories; pleomorphic/round cells and dendritiform cells with varying appearances, with the latter being predominant in normal eyes. A network of MHC class II positive dendritic cells was found in the choroid, beneath the RPE, with a density of 659 (96) cells/mm2. No MHC class II positive cells were found in the macrophage layer bordering the sclera. LPS injection caused a massive influx of ED1 positive macrophages in the area below the RPE cells but did not result in an influx of macrophages at the scleral side of the choroid. The infiltrate reached a maximum at 16 hours following LPS injection and decreased at 96 hours. The morphology of the infiltrating cells was pleomorphic/round at early stages of inflammation and changed into a dendritiform cell population later. The number of MHC class II positive cells on the anterior side of the choroid increased 8 hours after injection and reached a peak at 72-96 hours. MHC class II positive cells were not observed in the vicinity of the sclera at any time after LPS injection. Both resident and MHC class II positive dendritic cell numbers returned to normal values at day 14 following LPS injection.
CONCLUSIONS—These results indicate that the choroid is severely inflamed after systemic LPS administration to Lewis rats and suggests that endotoxin induced uveitis may serve as a model for generalised uveitis in humans.



Full Text

The Full Text of this article is available as a PDF (201.6 KB).

Figure 1  .

Figure 1  

Open in a new tab

Immunohistochemical staining of choroidal wholemounts with monoclonal antibody ED1. Wholemounts were obtained from normal Lewis rats (A, B) and at different time points after footpad lipopolysaccharide injection: 16 hours (C), 96 hours (D), day 7 (E), and day 14 (F). In normal rats, ED1 positive cells were present in the inner `RPE bordering' layer (A) and an outer layer adjacent to the sclera (B). Note the presence of ED1 positive cells after the RPE layer was brushed off (E); the remaining RPE is still detectable as faintly stained hexagonal cells in the right hand bottom corner (E). Magnification bar in (A) equals 250 µm and refers to all parts of the figure.

Figure 2  .

Figure 2  

Open in a new tab

Immunohistochemical staining of choroidal wholemounts with monoclonal antibody OX6 (A, B). Wholemounts were obtained from a normal Lewis rat (A) and 96 hours after footpad LPS injection (B). Note the presence of OX6 positive cells after partial removal of the RPE layer (A); the RPE layer is still visible as faintly stained hexagonal cells in the right, one third, part of (A). Magnification bar in (A) equals 250 µm and refers to both parts of the figure.

Figure 3  .

Figure 3  

Open in a new tab

Dynamics of pleomorphic (A) and dendritiform (B) ED1 positive cell numbers in the choroid after systemic LPS injection. The density of cells was scored as + (normal, low number), ++ (mild to moderate number), or +++ (high number).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Ben Ezra D., Forrester J. V. Fundal white dots: the spectrum of a similar pathological process. Br J Ophthalmol. 1995 Sep;79(9):856–860. doi: 10.1136/bjo.79.9.856. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Choudhury A., Pakalnis V. A., Bowers W. E. Characterization and functional activity of dendritic cells from rat choroid. Exp Eye Res. 1994 Sep;59(3):297–304. doi: 10.1006/exer.1994.1111. [DOI] [PubMed] [Google Scholar]
  3. Dijkstra C. D., Döpp E. A., Joling P., Kraal G. The heterogeneity of mononuclear phagocytes in lymphoid organs: distinct macrophage subpopulations in the rat recognized by monoclonal antibodies ED1, ED2 and ED3. Immunology. 1985 Mar;54(3):589–599. [PMC free article] [PubMed] [Google Scholar]
  4. Forrester J. V., McMenamin P. G., Holthouse I., Lumsden L., Liversidge J. Localization and characterization of major histocompatibility complex class II-positive cells in the posterior segment of the eye: implications for induction of autoimmune uveoretinitis. Invest Ophthalmol Vis Sci. 1994 Jan;35(1):64–77. [PubMed] [Google Scholar]
  5. Gery I., Streilein J. W. Autoimmunity in the eye and its regulation. Curr Opin Immunol. 1994 Dec;6(6):938–945. doi: 10.1016/0952-7915(94)90017-5. [DOI] [PubMed] [Google Scholar]
  6. Holt P. G., Degebrodt A., O'Leary C., Krska K., Plozza T. T cell activation by antigen-presenting cells from lung tissue digests: suppression by endogenous macrophages. Clin Exp Immunol. 1985 Dec;62(3):586–593. [PMC free article] [PubMed] [Google Scholar]
  7. Holt P. G., Schon-Hegrad M. A., Oliver J. MHC class II antigen-bearing dendritic cells in pulmonary tissues of the rat. Regulation of antigen presentation activity by endogenous macrophage populations. J Exp Med. 1988 Feb 1;167(2):262–274. doi: 10.1084/jem.167.2.262. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. McMenamin P. G., Crewe J. Endotoxin-induced uveitis. Kinetics and phenotype of the inflammatory cell infiltrate and the response of the resident tissue macrophages and dendritic cells in the iris and ciliary body. Invest Ophthalmol Vis Sci. 1995 Sep;36(10):1949–1959. [PubMed] [Google Scholar]
  9. McMenamin P. G., Crewe J., Morrison S., Holt P. G. Immunomorphologic studies of macrophages and MHC class II-positive dendritic cells in the iris and ciliary body of the rat, mouse, and human eye. Invest Ophthalmol Vis Sci. 1994 Jul;35(8):3234–3250. [PubMed] [Google Scholar]
  10. Okumura A., Mochizuki M. Endotoxin-induced uveitis in rats: morphological and biochemical study. Jpn J Ophthalmol. 1988;32(4):457–465. [PubMed] [Google Scholar]
  11. Ruiz-Moreno J. M., Thillaye B., de Kozak Y. Retino-choroidal changes in endotoxin-induced uveitis in the rat. Ophthalmic Res. 1992;24(3):162–168. doi: 10.1159/000267163. [DOI] [PubMed] [Google Scholar]
  12. Yang P., de Vos A. F., Kijlstra A. Macrophages in the retina of normal Lewis rats and their dynamics after injection of lipopolysaccharide. Invest Ophthalmol Vis Sci. 1996 Jan;37(1):77–85. [PubMed] [Google Scholar]
  13. de Vos A. F., Klaren V. N., Kijlstra A. Expression of multiple cytokines and IL-1RA in the uvea and retina during endotoxin-induced uveitis in the rat. Invest Ophthalmol Vis Sci. 1994 Oct;35(11):3873–3883. [PubMed] [Google Scholar]

Articles from The British Journal of Ophthalmology are provided here courtesy of BMJ Publishing Group

RESOURCES