MAJOR HISTOCOMPATIBILITY COMPLEX CLASS I-RESTRICTED PRESENTATION OF INFLUENZA-VIRUS NUCLEOPROTEIN PEPTIDE BY B-LYMPHOMA-CELLS HARBORING AN ANTIBODY GENE ANTIGENIZED WITH THE VIRUS PEPTIDE

We analyzed the capacity of B cells to process and present a peptide f rom the variable region of an endogenous immunoglobulin heavy (H) chai n to a major histocompatibility complex (MHC) class I-restricted cytot oxic Tlymphocyte (CTL) clone. The H-chain gene was engineered to expre ss 14-amino acid peptide from the sequence of the influenza virus nucl eoprotein (NP) antigen in the third complementarity-determining region (CDR3). This NP peptide is presented in association with the D-b alle le in H-2(b) mice, We demonstrate that B lymphoma cells (H-2(b)) harbo ring the antigenized H-chain gene process and present the NP peptide i n association with the D-b molecule and are lysed by a CTL clone speci fic for that peptide in an MHC-restricted way. In contrast, the solubl e antigenized antibody failed to mediate lysis of H-2(b) target cells. The endogenously processed immunoglobulin CDR3 peptide could be elute d from surface D-b molecules in transfected cells. This study formally demonstrates that peptides from the hypervariable loops of endogenous immunoglobulin are processed through the endogenous degradative pathw ay and are presented to CD8(+) T cells in the context of MHC class I m olecules. The implication of these findings for processing and present ation of endogenous immunoglobulin peptides in B cells and network reg ulation by idiopeptides is discussed.