Cells expressing an H chain Ig gene carrying a viral T cell epitope are lysed by specific cytolytic T cells

The epitope corresponding to amino acid residues 147-161 of the nucleoprotein (NP) of influenza A virus is recognized by CTL in association with H-2K^d class I Ag. Herein, we engineered an Ig molecule carrying this CTL epitope by replacing the diversity gene segment of the H chain V region of an antiarsonate antibody with an oligonucleotide that encodes the CTL epitope. The chimeric H chain gene was expressed either alone or together with the parental L chain in the nonsecreting BALB/c myeloma B cell line, SP2/0. The Ig produced by cells transfected with both the chimeric H chain and parental L chains genes expressed the NP epitope but lost the original arsonate binding activity. In addition, SP2/0 cells expressing the chimeric H chain either alone or together with the parental L chain were lysed by class I restricted NP-epitope specific CTL. By contrast, SP2/0 cells pulsed with soluble chimeric Ig molecules were not lysed by the specific CTL. These observations indicate that: 1) this particular CTL epitope can be expressed on Ig molecules without altering the H and L chain pairing; 2) this CTL epitope can be generated from this chimeric Ig in which it is surrounded by flanking regions distinct from those of the viral NP; and 3) the generation of this CTL epitope from the Ig molecule requires the endogenous pathway as do viral proteins.