Cornea of Naive Mice is Endowed With Both CD4+ and CD8+ T Cells

Abstract

Purpose:: To determine if corneas of naive mice contain resident CD4⁺ and CD8⁺ T cells.

Methods:: Corneas of naive BALB/c, C57BL/6, or SCID control mice were immuno-stained with anti-CD4 (clone RM4-5) and anti-CD8 (clone 5H10-1) mAbs and the presence of T cells in intact corneas or corneal sections were monitored by confocal or light microscopy, respectively. In addition, expression of CD4 and CD8 mRNAs in corneas was determined by TaqMan RT-PCR and compared with their relative expression in spleens.

Results:: Both confocal microscopy on intact whole corneas and light microscopy on corneal sections detected anti-CD4 and anti-CD8 stained cells in the central and peripheral corneas of C57BL/6 mice. In BALB/c mice confocal microscopy detected anti-CD4⁺ stained cells in the central and peripheral cornea but not anti-CD8⁺, while both CD4⁺ and CD8⁺ cells were detected by light microscopy. No stained cells were detected in control SCID mice. Using RT-PCR, we detected both CD4 and CD8 mRNAs in corneas of BALB/c and C57BL/6 mice, with markedly lower transcripts levels in SCID mice. Among the three groups of mice C57BL/6 mice had higher mRNA transcript levels for CD4 and CD8 consistent with the immuno-staining results.

Conclusions:: It appears that: (1) Both CD4⁺ and CD8⁺ T cells are present in naive mouse corneas; and (2) the level of CD4 and CD8 transcripts in BALB/c and C57BL/6 but not SCID mice reflect the immunostaining results.

Keywords: herpes simplex virus • keratitis • pathology: human