PROTECTIVE MUCOSAL IMMUNITY ELICITED BY TARGETED ILIAC LYMPH-NODE IMMUNIZATION WITH A SUBUNIT SIV ENVELOPE AND CORE VACCINE IN MACAQUES

Prevention of sexually transmitted HIV infection was investigated in m acaques by immunization with a recombinant SIV (simian immunodeficienc y virus) envelope gp120 and core p27 vaccine. In two independent serie s of experiments, we used the novel targeted iliac lymph node (TILN) r oute of immunization, aiming close to the iliac lymph nodes draining t he genitorectal mucosa. Rectal challenge with the SIVmac 32H J5 molecu lar clone in two series induced total protection in four out of seven macaques immunized by TILN, compared with infection in 13 of 14 unimmu nized macaques or immunized by other routes (P = 0.025). The remaining three macaques showed either a decrease in viral load (>90%) or trans ient viremia, indicating that all seven TILN-immunized macaques showed total or partial protection (P = 0.001). Protection was associated wi th significant increase in the iliac lymph nodes of IgA antibody-secre ting cells to p27 (P < 0.02), CD8-suppressor factor (P < 0.01), and th e chemokines RANTES and MIP-1 beta (P < 0.01).