Female Reproductive Tract

Carrageenan Formulation Prevents Macrophage Trafficking from Vagina: Implications for Microbicide Development

Abstract

Considerable evidence suggests that HIV-infected macrophages and/or lymphocytes may mediate sexual transmission of HIV. Our laboratory and other laboratories 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 aim of this study was to assess the extent of mononuclear cells trafficking from the vagina and to test the possibility that carrageenan formulation, a sulfated polysaccharide formulation containing 3% PDR98-15 carrageenan (FMC Biopolymer, Rockland ME - PC-515), a vaginal microbicide, would prevent vaginal transmigration of macrophages. When we inoculated supravitally stained mouse macrophages and T cells into the vagina of recipient mice, we observed that discrete numbers of donor?s cells migrated to the recipients? iliac and inguinal lymph nodes and to the spleen as well. When recipient mice were pre-inoculated with the carrageenan formulation, the number of macrophages in lymph nodes and spleen was reduced by greater than 90%. In contrast, a methylcellulose formulation, which is believed to be inactive, did not reduce migration to the lymphoid organs significantly. Our findings suggest that the carrageenan formulation blocks cell trafficking of macrophages from vagina and that blocking does not result from cytotoxicity. We speculate that blocking cell trafficking may help to prevent sexual transmission of HIV.