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Breast milk is a vehicle of infection and source of protection in post-natal mother-to-child HIV-1 transmission (MTCT). Understanding the mechanism by which breast milk limits vertical transmission will provide critical insight into the design of preventive and therapeutic approaches to interrupt HIV-1 mucosal transmission. However, characterization of the inhibitory activity of breast milk in human intestinal mucosa, the portal of entry in postnatal MTCT, has been constrained by the limited availability of primary mucosal target cells and tissues to recapitulate mucosal transmission ex vivo. Here, we characterized the impact of skimmed breast milk, breast milk antibodies (Igs) and non-Ig components from HIV-1-infected Ugandan women on the major events of HIV-1 mucosal transmission using primary human intestinal cells and tissues. HIV-1-specific IgG antibodies and non-Ig components in breast milk inhibited the uptake of Ugandan HIV-1 isolates by primary human intestinal epithelial cells, viral replication in and transport of HIV-1- bearing dendritic cells through the human intestinal mucosa. Breast milk HIV-1-specific IgG and IgA, as well as innate factors, blocked the uptake and transport of HIV-1 through intestinal mucosa. Thus, breast milk components have distinct and complementary effects in reducing HIV-1 uptake, transport through and replication in the intestinal mucosa and, therefore, likely contribute to preventing postnatal HIV-1 transmission. Our data suggests that a successful preventive or therapeutic approach would require multiple immune factors acting at multiple steps in the HIV-1 mucosal transmission process.

Background: Lymph nodes and gut-associated lymphatic tissue are important reservoirs of the human immunodeficiency virus (HIV). Little is known about these reservoirs in different geographic populations. We report the surgical outcomes of excisional lymph node and anorectal mucosal biopsies performed internationally and describe the lessons learned., Methods: Patients were recruited through the Joint Clinical Research Center (JCRC) in Kampala, Uganda, where procedures were performed. Studies were approved by the Institutional Review Boards of the JCRC and the University of Minnesota. Instruments and supplies were shipped to Uganda and prepared onsite. Drugs and skin preparations were purchased locally. Lymph nodes were removed through 1-3 cm incisions with ligatures on lymphovascular pedicles. Incisions were closed with subcuticular sutures and epidermal tape. Two to four pieces of anorectal mucosa were obtained through anoscopes using biopsy forceps., Results: One hundred thirty-eight lymph node biopsies and 98 anorectal mucosal biopsies were performed on 71 patients. Forty-one patients were HIV-positive. Many patients had multiple procedures. Two minor complications resulted: One hematoma and one lymphocele. Despite the cost of travel and lodging, cost per biopsy was lower in Uganda compared with the United States., Conclusion: Invasive clinical research can be performed with minimal morbidity in emerging nations with outcomes similar to those found in the United States, but with lower cost.