Immunoglobulins From Resistant Sex Workers May Provide Protection.(Brief Article)

2001 NOV 7 - (NewsRx.com & NewsRx.net) -- by Michael Greer, senior medical writer - HIV specific immunoglobulin from persistently uninfected sex workers may aid in the development of an HIV vaccine effective against a wide range of viral strains, researchers in a multicenter study say.

"Although HIV specific cellular immune responses are found in a number of HIV highly exposed, persistently seronegative (HEPS) cohorts, late seroconversion can occur despite pre-existing cytotoxic T lymphocytes (CTL), suggesting that a protective HIV vaccine may need to induce a broader range of HIV-specific immune responses," explained Kristina Broliden at the Karolinska Institute in Stockhom, Sweden, and colleagues in Kenya, Italy, Canada, and the U.K.

Immunoglobulin A (IgA) from HEPS sex workers in Nairobi seems to act independently of CTL responses and to confer HIV protection even at low doses, according to Broliden and coauthors.

The researchers purified IgA found at low levels in the plasma, saliva, and genital tract mucosa of Nairobi-based HEPS sex workers. Purified IgA was able to prevent peripheral blood mononuclear cell (PBMC) infection by HIV from clades A and D, which are common in Kenya, and clade B, which is not.

Broliden and team also evaluated the efficacy of IgA from HEPS women in a model of human mucosal epithelium. The protein was able to specifically block HIV transcytosis through epithelial cells, they reported.