Figure 3. Identification of a HERV-K(HML-2)-Env–specific CD8⁺ T cell response and fine mapping of the T cell determinant.

(A and B) IFN-γ ELISPOT was performed on PBMCs from the HIV-1–infected elite controller OM9. Results depicting mean sfu per 10⁶ PBMCs, with error bars representing standard deviation, are shown. (A) All tests were performed in duplicate. The dashed line represents the threshold for a positive response as defined by meeting the criteria of >3x background and >50 sfu per million PBMCs after background subtraction. (B) All tests were performed in quadruplicate. (C and D) IFN-γ ELISPOT was performed on a HERV-K(HML-2)-Env–specific CD8⁺ T cell clone from OM9. (C) The specificity of the HERV-K(HML-2)-Env–specific clone was confirmed using the original CIDSTFNWQHRILLV peptide (crude) and a newly synthesized batch of the same peptide (>98% pure) and fine mapped using a panel of truncated peptides. IFN-γ ELISPOT data depicting mean spots per 10⁶ clone cells (tested in duplicate), with error bars representing standard deviation, are shown. (D) The reactivity of the HERV-K(HML-2)-Env–specific T cell clone to serial dilutions of the indicated peptides was tested in the presence of autologous BLCLs. Tests were performed in triplicate, and error bars represent SEM.