CD8A and infection: The “enough and soon enough” hypothesis predicts: 1) that SIV-delta nef vaccination would elicit/establish a resident or rapid responder population of CD8 T cells located at the right time and place to contain infection following vaginal challenge at the portal of entry, or after dissemination to LTs; and 2) that the resident or responder populations will be distinguished by location, numbers or functions that might correlate with the maturation of protection between 5 and 20 weeks after SIVΔnef vaccination.