Murine conjunctival tolerance and the fate of antigen specific T cells

Purpose. To determine whether conjunctival tolerance occurs in the mouse. Conjunctiva associated lymphoid tissue is histologically similar to other mucosa associated lymphoid tissue. Antigens encountered by the gut associated lymphoid tissue frequently induce a state of tolerance rather than sensitization. Results. Using BALB/c mice we have found that instillation of 2.5 ug of ovalbumin (OVA) twice a day for ten days or 25 ug of OVA once a day for ten days by drops into the murine conjunctiva followed in three days by 100 ug of OVA in CFA s.c. resulted in an antigen specific decrease in responses to OVA. The concentration of antigen required was over a 100-fold less than that required for the induction of oral tolerance. Using an adoptive transfer model described by Kearney et al (Immunity 1:327, 1994), BALB/c mice received a limiting number of OVA peptide (323-339) specific CD4+ T cells from a D011.10 TCR transgenic mouse and antigen specific T cells followed using anti-TCR antibody (KJ126). Flow cytometry demonstrated an increase in Tg T cells in submandibular LN's 3 and 6 days following OVA peptide (25 ug) dropped into the conjunctiva but little increase in other draining or distant LN's including mesenteric or spleen. The Tg T cells were primarily in the paracortical region of LN with a few having entered the follicle. Subsequent administration of CFA/OVA peptide (100 ug) in the back following 10 days of conjunctival drops caused a greater increase in Tg T cells in submandibular than axillary or inguinal LN's in the conjunctivally tolerized mice. The percentage of Tg T cells in the axillary/inguinal LN's following conjunctival antigen was 4 fold fewer than the percentage of Tg T cells in the LN's of controls that received only CFA/OVA pep in the back. Conclusion. Antigen encountering murine CALT induces a state of tolerance at antigen concentrations much lower than orally administered antigen.