OVA-specific CD8+ T cells do not express granzyme B during anterior chamber associated immune deviation

To examine antigen (Ag)-specific CTL response during anterior chamber associated immune deviation (ACAID).

OVA or OVA257-264 peptide was injected into the anterior chamber (AC) of C57BL/6 mice. There were 16 mice in each ACAID group induced with OVA or OVA257-264 peptide. The mice were primed by SC injection with OVA or OVA 257-264 peptide in complete Freund's adjuvant (CFA) on day 7. Ag-specific CD8+ T cells in spleens were analyzed on day 14 using Pentamer H-2K(b)-SIINFEKL(OVA257-264 peptide). IFN-gamma ELISPOT and intracellular granzyme B staining were used to characterize the CTL response. Twelve mice in each group immunized with OVA or OVA257-264 peptide in CFA served as positive controls. Twelve normal mice served as negative controls and 12 receiving injection of CFA as CFA controls for studying the influence of CFA on the Ag-specific CTL response.

The results showed that anterior chamber inoculation of OVA or OVA257-264 peptide could induce ACAID as evidenced by an impaired DTH response. The frequency of Ag-specific CD8+ T cells in ACAID mice was not different from that in mice challenged with Ags in CFA only (positive controls). IFN-gamma production by these cells in ACAID mice was not different compared to positive controls. However, Ag-specific CD8+ T cells in ACAID mice failed to secrete granzyme B. Mice challenged only with OVA peptide and CFA also showed a granzyme B negative CD8+ T cell response. Ag-specific CTL response induced by CFA alone was similar with the negative control.

These results show that the frequency of Ag-specific CD8+ T cells is not altered during ACAID. The Ag-specific CTL response during ACAID is characterized by the absence of granzyme B expression.