Figure 4. MHC involvement in target recognition. (A and B) Tumor-infiltrating lymphocytes (TILs) were stimulated with autologous tumor cells preincubated with isotype control or a combination of MHC Class I and II-blocking antibodies. While MHC Class I and Class II-blocking antibodies significantly affected tumor cell recognition by αβ T cells (B), they did not modify tumor cell recognition by Vδ1 T cells (A).