Infectious human immunodeficiency virus can rapidly penetrate a tight human epithelial barrier by transcytosis in a process impaired by mucosal immunoglobulins

Mucosal surfaces are the main natural site of entry into the body for human immunodeficiency virus (HIV). Herein, an alternative mechanism for virus s pread is described. The mechanism, which involves transcytosis of endosome- internalized HIV-particles, was generated by contact of HIV-infected cells with the apical surface of an epithelial cell line. Transcytosed viruses ra pidly (in 20-30 min) access the serosal side of the epithelial barrier with out infecting the epithelium itself In turn, transcytosed HIV could infect host submucosal mononucleated target cells, and thus the infection could sp read. An investigation was done to determine whether mucosal antibodies cou ld block HIV transcytosis. Both secretory IgA (S-IgA) and IgG that were pur ified from colostrum from HIV-seropositive women impaired HIV transcytosis, irrespective of the level of the recombinant HIV envelope anti-gp 160-spec ific activities in an ELISA. However, specific S-IgAs were more efficient t han IgC. Therefore, mucosal-specific S-IgA to HIV-1 could be relevant to re ducing infectivity of HIV-1 in corporeal fluids.