Prevention of pneumococcal otitis media in chinchillas with human bacterial polysaccharide immune globulin.

Clinical and experimental observations suggest that immune globulin may prevent otitis media (OM) in children. We performed experiments in chinchillas to test the hypothesis that human bacterial polysaccharide immune globulin (BPIG) might prevent OM caused by Streptococcus pneumoniae. Animals were given BPIG or saline intraperitoneally on day 0. On day 3 the epitympanic bulla was inoculated with S. pneumoniae type 7F. All 12 saline-treated and none of 12 BPIG-treated animals developed pneumococcal OM by day 7 (P less than 0.0001). Bacteremia developed in 6 of 12 saline- and 0 of 12 BPIG-treated animals (P = 0.007). Death with pneumococcal OM occurred within 28 days in 5 of 12 saline- and 0 of 12 BPIG-injected animals (P = 0.02). A chinchilla-specific immunoassay was used to show that surviving saline-injected animals developed serum anticapsular antibody; BPIG-treated animals had no detectable response. At levels of anticapsular immunoglobulin G similar to those of human adults, BPIG given systemically prevented pneumococcal OM and disseminated infection in chinchillas. BPIG may be of value in preventing human bacterial infection and may also inhibit development of antibody if it affects local infection or colonization. Specific immunoglobulin G antibody may provide an important antibacterial defense of mucosal surfaces of the respiratory tract.