Babies of human immunodeficiency virus (HIV)-infected mothers ingest large titers of HIV when they breastfeed, but how most of these children escape infection has remained unclear. In August Journal of Virology, Steffanie Sabbaj and colleagues at the University of Alabama at Birmingham, US, show that breast milk of HIV-infected women contains cytolytic HIV-specific CD8⁺ T cells that may protect babies from HIV infection (J Virol 2002, 76:7365-7373).

Sabbaj et al. investigated the ability of breast milk cells (BMC) from HIV-infected women to respond to HIV-1 peptides in a gamma interferon enzyme-linked immunospot assay. They observed that these BMCs had responses to pools of Gag, Pol, Nef and Env peptides. But of four HIV-negative women, none responded to any of the tested HIV peptide pools. In addition, depletion and tetramer staining studies showed that CD8⁺ T cells mediated these responses, and that BMC were...