Abstract
Purpose: :
Previously we demonstrated an increase in CCR5 and CCR2 RNA in iris cells after the intracameral injection of antigen. Here we investigated (i) the expression of Qa-1,essential to the induction of regulatory T cells in Anterior Chamber-Associated Immune Deviation (ACAID), (ii) the expression of chemokine receptor CCR5 on F4/80+ cells in the iris, thymus and spleen after the intracameral / anterior chamber (AC) injection of antigen and (iii) a role for CCR2 in the recruitment of F4/80+ peripheral blood cells (PBMC) to the iris and and transfer of the suppression of hypersensitivity.
Methods: :
Ovalumin (OVA) or trinitrophenylated bovine albumin (TNP-BSA) was injected into an AC of DBA/2, BALB/c, C57BL/6 mice. FACS and confocal microscopy were used to characterize the expression of F4/80 and CCR5 by iris cells and thymocytes recovered 24 h after the intracameral injection of antigen and/or iv injection of CFSE-labeled PBMC from CCR2 -/- or +/+ mice. Delayed-type hypersensitivity (DTH) to TNP-BSA was measured in the footpads of TNP-BSA-immunized mice that received CCR2+ and CCR2- PBMC recovered from donors receiving AC, TNP-BSA.
Results: :
Iris cells and thymocytes from ACAID-deficient DBA/2J mice are deficient in Qa-1b-expressing cells as compared to ACAID-competent DBA/2NCr mice. A higher frequency of F4/80+, Qa-1b+ cells was found in the irides and thymocytes of DBA/2NCr mice that received an AC injection of antigen. The number of F4/80+, CCR5+ cells increased in the irides of mice receiving an AC injection of antigen. F4/80+ PBMC from CCR2-/- mice failed to migrate to the iris, thymus or spleen after AC injection or transfer the suppression of DTH.
Keywords: ACAID • anterior chamber • immune tolerance/privilege