Oligoclonal expansion of T cell receptor V beta 2 and 3 cells in the livers of mice with graft‐versus‐host disease

The nonsuppurrative destructive cholangitis lesions in the B10.D2 (donor) into BALB/c (host) mouse graft‐versus‐host disease (GVHD) model are dependent on CD4 T cells that use a T cell receptor‐β chain variable region (Vβ) repertoire, which is heavily biased toward Vβ2 and Vβ3 usage. We hypothesized that liver Vβ2 + and Vβ3 + CD4 T cells originate from donor mice and recognize BALB/c minor histocompatibility alloantigens and BALB/c endogenous retroviral superantigen‐6, respectively. To test this hypothesis, we determined the donor:host chimera status of infiltrating liver lymphocytes and the clonal states of liver Vβ2 + and liver Vβ3 + CD4 cells isolated from GVHD mice. A limited donor TCR Vβ repertoire composed of Vβ1 + , 2 + , 3 + , 4 + , 6 + , and 8 + cells infiltrated the livers of GVHD mice on day 3. Consistent with a response to immunodominant host minor histocompatibility antigens, we detected oligoclonal liver Vβ2 + T cells in 40% of GVHD mice studied on day 3 and in 100% of GVHD mice studied on day 14. Typical of superantigen stimulation, extremely polyclonal liver Vβ3 + T cells were detected in 100% of GVHD mice studied on day 3 and 40% of GVHD mice studied on day 14. Yet, the liver Vβ3 + T cells in 60% of the day 14 GVHD mice were oligoclonal, pointing to a response to minor histocompatibility antigens.