Bacterial barrier to HIV

The vaginal mucosa is colonized by commensal bacteria, primarily lactobacilli. Although the dominance of lactobacilli over pathogenic anaerobes is positively associated with vaginal health, these bacteria are not protective against the HIV virus, and there are few means by which women can actively protect themselves against HIV infection. In the September 8 early edition of PNAS, Theresa L.-Y. Chang and colleagues at Stanford University show that a natural human isolate of Lactobacillus jensenii engineered to express functional two-domain CD4 can inhibit HIV infectivity in vitro and may enhance vaginal protection (PNAS, DOI:10.1073/pnas.1934747100, September 8, 2003).

Chang et al. collected human vaginal samples of L. jensenii and engineered the bacteria to secrete two-domain CD4 (2D CD4) HIV-binding proteins. They used an HIV-1HxB2 in vitro infection assay and observed that Lactobacillus-derived 2D CD4 inhibited HIV-1 entry into target cells in a dose-dependent manner. In addition, they showed that coincubation of the engineered ...