Mucosa and vaccine-induced immune protection in nonhuman primates

Purpose of review The purpose of this article is to review some of the recent progress in the development of HIV vaccines that induce immune responses in mucosal tissues that may correlate with protection of the mucosal CD4 T cell compartment. Recent findings Mucosal tissues are the primary sites for viral entry and the resident CD4 T cells serve as readily available target cells for active infection. Viral entry is associated with a massive destruction of these cells. The resident CD4 cells are memory T cells and hence play an important role in the generation of secondary immune responses. Protecting these CD4 T cells is critical for controlling viral infection and for preserving immune competence. Numerous mucosal vaccine regimens currently under development have been shown to induce both B and T cell responses in mucosal tissues. Though induction of neutralizing antibodies still remains an elusive goal, the demonstration that antibodies can have a protective role through alternative mechanisms offers hope that humoral responses can be harnessed to yield a protective response in mucosal tissues. Summary The mucosal immune system is highly compartmentalized and hence immunization regimens need to target mucosal tissues to be successful in inducing protective immune responses in mucosal tissues.