Transmission of HIV-1 during breastfeeding is a significant source of new pediatric infections in sub-Saharan Africa. Breast milk from HIV-positive mothers contains both cell-free and cell-associated virus; however, the impact of breast milk on HIV-1 infectivity remains poorly understood. In the present study, breast milk was collected from HIV-positive and HIV-negative Tanzanian women attending antenatal clinics in Dar es Salaam. Milk was analyzed for activity in vitro against both cell-free and cell-associated HIV-1. Potent inhibition of cell-free R5 and X4 HIV-1 occurred in the presence of milk from all donors regardless of HIV-1 serostatus. Inhibition of cell-free HIV-1 infection positively correlated with milk levels of sialyl-LewisXfrom HIV-positive donors. In contrast, milk from 8 of 16 subjects enhanced infection with cell-associated HIV-1 regardless of donor serostatus. Milk from two of these subjects contained high levels of multiple pro-inflammatory cytokines including TNFa, IL-1b, IL-6, IL-8, MIP-1a, MIP-1b, MCP-1 and IP-10, and enhanced cell-associated HIV-1 infection at dilutions as high as 1:500. These findings indicate that breast milk contains innate factors with divergent activity against cell-free and cell- associated HIV-1 in vitro. Enhancement of cell-associated HIV-1 infection by breast milk may be associated with inflammatory conditions in the mother and may contribute to infant infection during breastfeeding.
Lyimo, Magdalena A.; Mosi, Matilda Ngarina; Housman, Molly L.; Zain-Ul-Abideen, Muhammad; Lee, Frederick V.; Howell, Alexandra L.; and Connor, Ruth I., "Breast Milk from Tanzanian Women Has Divergent Effects on Cell-Free and Cell-Associated HIV-1 Infection In Vitro" (2012). Open Dartmouth: Faculty Open Access Articles. 2569.