A NASAL WHOLE-CELL PERTUSSIS-VACCINE CAN INDUCE STRONG SYSTEMIC AND MUCOSAL ANTIBODY-RESPONSES WHICH ARE NOT ENHANCED BY CHOLERA-TOXIN

The immunogenicity of formaldehyde-inactivated Bordetella pertussis (B p) delivered by the intranasal or colonic-rectal routes in BALB/c mice was studied by immunization four times at weekly intervals with Bp al one, or with Bp mixed with cholera toxin (CT) as a mucosal adjuvant. M ice given Bp subcutaneously and untreated mice sewed as controls. Anti body responses in serum, saliva, bronchoalveolar lavage (BAL) fluids a nd extracts of faeces were measured by enzyme-linked immunosorbent ass ay. Nasal immunizations with Bp alone induced high levels of Ige antib odies to Bp in serum and BAL fluids, as well as IgA antibodies in seru m, saliva, BAL fluids and extracts of faeces. The IgA responses were s ignificantly reduced, and the IgG responses Mere not increased, when C T was given intranasally together with Bp. However, CT increased the I gA responses to Bp in faeces when both antigens were given rectally, w hile rectal administration of Bp alone did not induce significant seru m or-secretory antibody responses. However when mixed with Bp, the CT itself induced antibodies to CT in serum and samples representing secr etions after both nasal and rectal administrations. Thus, Bp is strong ly immunogenic when applied intranasally, but not when presented into the intestinal lumen via the rectal route. It appears that CT, which i s known to be a mucosal adjuvant and which in itself is a strong mucos al immunogen, Mill inhibit the immune responses of other strong immuno gens when applied on the nasal mucosa. (C) 1997 Elsevier Science Ltd.