HIV/AIDS Transmission: Carrageenan Formulation Prevents Macrophage Trafficking From Vagina

"Considerable evidence exists that human immunodeficiency virus (HIV)-infected macrophages and/or lymphocytes may mediate sexual transmission of HIV," scientists in Italy explained recently.

According to M.E. Perotti and colleagues at the University of Milan, "We and others have previously demonstrated that when vitally stained donor mouse lymphocytes or macrophages are placed in the vaginas of mice, some of the stained cells can later be found in the iliac lymph nodes."

The investigators conducted a study "to assess the extent of mononuclear cell trafficking from the vagina and to test the possibility that carrageenan formulation, a sulfated polysaccharide formulation containing 3% PDR98-15 carrageenan (PC-515; FMC Biopolymer, Rockland, Maine), a vaginal microbicide, would prevent vaginal transmigration of macrophages."

"When supravitally stained mouse macrophages and T cells were inoculated into the vagina of recipient mice, discrete numbers of donor cells migrated to the recipient iliac and inguinal lymph nodes and spleen," they reported. "When recipient mice were preinoculated with the carrageenan formulation, the number of macrophages in lymph nodes and spleen was reduced by more than 90%."

"In contrast, a methylcellulose formulation, which is believed to be inactive, did not significantly reduce migration to the lymphoid organs," test results showed.

"Our findings suggest that the carrageenan formulation blocks cell trafficking of macrophages from vagina and the blocking does not result from cytotoxicity," the scientists concluded. "Blocking cell trafficking may help to prevent sexual transmission of HIV," they wrote in their study, "Carrageenan Formulation Prevents Macrophage Trafficking from Vagina: Implications for Microbicide Development," which was published in Biology of Reproduction (2003;69(3):933-939).

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