THE BABOON AS A NONHUMAN PRIMATE MODEL FOR ASSESSING THE EFFECTS OF MATERNAL IMMUNIZATION WITH HAEMOPHILUS-INFLUENZAE TYPE-B POLYSACCHARIDEVACCINES

These studies were performed to assess the utility of the baboon as a nonhuman primate model to evaluate vaccines for use in humans. Specifi cally, we examined the antibody response of baboons immunized during t he third trimester of pregnancy with Haemophilus influenzae type b (Hi b) polyribosylribitol phosphate (PRP) conjugate and unconjugated polys accharide vaccines. Some of the vaccinated mothers failed to respond t o a single immunization with unconjugated Hib PRP, Specific Hib PRP im munoglobulin G (IgG) but not IgM antibodies cross the baboon placenta and are detected in the offspring. Higher-titer baboon anti-Hib PRP di d not express two previously defined cross-reactive human anti-Hib PRP idiotypes and was biased towards lambda light-chain expression. Spect rotype analysis indicated that baboon anti-Hib PRP was restricted in h eterogeneity and oligoclonal.