CHARACTERIZATION OF HUMAN CD4-SF2 NEF-SPECIFIC T-CELL CLONES FOR ANTIGEN-PROCESSING AND PRESENTATION REQUIREMENTS AND FOR CYTOTOXIC ACTIVITY(, HIV)

We have described previously the generation of seven HIV-SF2 Nef-speci fic, CD4 + T-cell clones, identification of epitopes within which al e recognized by these clones, and the MHC alleles that restrict their r esponses(1). In this study, we have extended this characterization to include evaluation of antigen-processing and presentation requirements and cytotoxic activity. Clones were generated from five HIV-1 uninfec ted donors by in vitro stimulation of periphel al blood mononuclear ce lls with purified recombinant Nef(1) In experiments with fixed cells, with the exception of two clones, recognition of Nef, but not Nef pept ides, required processing. Also, at higher concentrations of antigen, the clones themselves were capable of presenting Nef peptides, but not soluble Nef. All clones had the ability to specifically lyse autologo us, Epstein-Barr vine-transformed lines sensitized with Nef synthetic peptides, or, in some cases, soluble Nef. The cytotoxic activity mappe d to the same epitopes identified for the proliferative response (a.a. 14-22, 47-53, 68-77, 70-77, 195-203 and 185-192) and was restricted b y the same HLA class II molecules (DRw6, DQw7, DRw15(2), DR1 and DP5). Sensitization of the cytolytic clones with specific Nef peptides, but not soluble Nef, resulted in autolysis.