Non-H-2 Involvement in Antigen-Specific T Cell Proliferative Responses. I. Different Blocking Effect of Anti-Class II Monoclonal Antibodies between B6 and BAL

Abstract Two monoclonal antibodies (IAb1 and D2A2 mAbs) to I-A b molecule were shown to have different inhibitory effects between B6 and BALB.B mice in antigen-specific T cell activation. Antigen-specific T cell proliferative responses of B6 were blocked by IAb1 mAb but not by D2A2 mAb, whereas those of BALB.B were blocked by both IAb1 and D2A2 mAbs. The different blocking effect of D2A2 mAb between B6 and BALB.B is attributed to the APC level but not to responding T cell repertoires, because antigen-specific proliferative responses of (B6 × BALB.B)F1 T cells stimulated by BALB.B APC but not by B6 APC were blocked by D2A2 mAb. These data indicate that not only H-2 but also non-H-2 genes participate in antigen-specific activation of T cells by APC.