Cell-Associated Simian Immunodeficiency Virus Accelerates Initial Virus Spread and CD4+ T-Cell Depletion in the Intestinal Mucosa

Abstract Cell-free and cell-associated human immunodeficiency virus (HIV) may differently affect the immune system and the efficacy of prevention strategies. Here we examined mucosal events in simian immunodeficiency virus (SIV) infection, using infected cells together with cell-free virus and cell-free virus alone. Intravenously inoculated SIV-infected cells disseminated virus to the intestine within 16 hours. Infection with both virus forms accelerated viral dissemination in the intestinal mucosa and the loss of mucosal CD4+ T cells as compared to infection with cell-free virus only. As all natural sources of HIV infection contain both virus forms, future prevention studies should focus on efficacy against both cell-free and cell-associated virus. Infection with a mixture of cell-free and cell-associated simian immunodeficiency virus (SIV) accelerated viral dissemination and CD4+ T-cell depletion in the intestine as compared to infection with cell-free SIV alone. Consequently, a mixture of both virus forms should be used in treatment models.