Mechanisms of protection induced by attenuated simian immunodeficiency virus. IV. Protection against challenge with virus grown in autologous simian cells

: Attenuated simian immunodeficiency virus (SIV) induces potent protection against infection with wild‐type virus, but the mechanism of this immunity remains obscure. Allogeneic antibodies, which arise within animals as a result of SIV infection, might protect against challenge with exogenous SIV grown in allogeneic cells. To test this hypothesis, eight macaques were infected with attenuated SIV and subsequently challenged with wild‐type SIV grown in autologous cells or heterologous cells. The results clearly demonstrated that animals infected with attenuated SIV are protected against wild‐type SIV grown in autologous or heterologous cells. Thus, the hypothesis that live attenuated SIV protects by the induction of allogeneic antibodies is not tenable.