We therefore undertook studies of the location and dynamics of the immunodominant CD8 T cell response to vaccination with SIVmac239-Δnef and the response in vaccinated animals to high dose vaginal challenge with wild type SIVmac251 (hereafter, WT-SIV) to see if vaccination might induce and maintain a resident or rapid responder population of CD8 T cells that would be enough and soon enough to contain infection at the portal of entry or after dissemination to LTs. The gene discussed is CD8A; the disease is infection.