One I Region Restriction Determinant Can Associate with Multiple Antigenic Epitopes

Abstract

Studies presented in this paper show that T cell clones recognizing different epitopes of multideterminant antigens can be restricted by the same I-A molecule. These data further support the concept that a single I-A restriction site can present more than one antigenic epitope. This concept was supported by data on the proliferation of T cell clones reactive with either poly(L-Glu⁶⁰, L-Ala³⁰, L-Tyr¹⁰)_n (GAT) or poly(Tyr, Glu)-poly D, L-Ala--poly Lys [(T, G)-A--L] which recognized different epitopes on these multideterminant antigens. Two clones recognizing different epitopes on the same multideterminant antigen can be blocked by the same monoclonal anti-I-A antibody. Additionally, the mutation in the A^bm12 chain utilized in [B6.C-H-2^bm12(bm12)×B10.A(4R)]F₁ mice can affect the restriction determinant of clones recognizing different antigenic epitopes. These results suggest that in the strictest sense, the determinant selection theory is not tenable and would support the concept that T cell specificity is controlled by the T cell repertoire.