IFNG and HIV-1 infection: Of more than 200 breast-feeding HIV-1-exposed uninfected babies who were serially and prospectively assessed for HLA-selected HIV-1 peptide-specific cytotoxic T lymphocyte (CTL) IFN-γ responses by means of enzyme-linked immunospot (ELISpot) assays, almost half had HIV-1–specific CTL IFN-γ responses despite the absence of HIV-1 infection [26].