ADJUVANTICITY AND PROTECTIVE IMMUNITY ELICITED BY BORDETELLA-PERTUSSIS ANTIGENS ENCAPSULATED IN POLY(DL-LACTIDE-CO-GLYCOLIDE) MICROSPHERES

Purified Bordetella pertussis antigens, encapsulated in biodegradable poly(DL-lactide-co-glycolide) (DL-PLG) microspheres, were evaluated fo r their immunogenicity and ability to elicit a protective immune respo nse against B. pertussis respiratory infection, Microencapsulated pert ussis toroid, filamentous hemagglutinin, and pertactin all retained th eir immunogenicity when administered parenterally, Intranasal immuniza tion with a low dose (1 mu g) of encapsulated filamentous hemagglutini n, pertussis toroid, or pertactin elicited strong specific immunoglobu lin G and immunoglobulin A antibody responses in respiratory secretion s that were greater in magnitude than the responses elicited by the sa me doses of unencapsulated antigen. Intranasal immunization with as li ttle as 1 mu g of encapsulated pertussis antigen prior to infection re duced the bacterial recovery by 3 log(10) CFU. However, intranasal imm unization with the same low doses of unencapsulated antigens did not r educe infection. Intranasal administration of a combination of 1 mu g of each of the microencapsulated pertussis antigens was more effective in reducing bacterial infection than administration of any single mic roencapsulated antigen, Intranasal administration of microencapsulated B. pertussis antigens elicits high levels of specific antibody coinci ding with protection against infection when these microspheres are adm inistered to the respiratory tract, These data provide evidence of the respiratory adjuvanticity of three different DL-PLG microsphere prepa rations, each of which contains a unique B. pertussis antigen,