HIV Virions and HIV Infection in Vitro Are Unaffected by Human Granzymes A and B

Abstract

Granzymes are a family of serine proteinases commonly found in the granules of CD8⁺ T cells. In HIV infection, CD8⁺ cells show cytotoxic and noncytotoxic antiviral activities. The latter is mediated, at least in part, by a secreted CD8⁺ cell antiviral factor, CAF. Because of the antiviral nature of CD8⁺ cells, we examined the potential anti-HIV activity of free granzymes that can be found in CD8⁺ cell culture fluids. Pretreatment of CD4⁺ T cells with granzyme A or granzyme B had no effect on their susceptibility to infection with HIV, nor did incubation of the granzymes with HIV virions alter their infectivity. Continuous culture of acutely infected CD4⁺ T cells with granzyme A or B showed no effect on cell viability or the replication of HIV. The findings of this study suggest that free granzymes do not control HIV infection and spread in CD4⁺ T cells.