A nasal whole-cell pertussis vaccine induces specific systemic and cross-reactive mucosal antibody responses in human volunteers

A whole-cell pertussis vaccine, each dose consisting of 250 microg of protein, was given intranasally four times at weekly intervals to six adult volunteers. All vaccinees responded with increases in nasal fluid IgA antibodies to Bordetella pertussis whole-cell antigen. Three vaccinees with high nasal antibody responses also developed increased serum IgA and IgG antibodies to this antigen. Salivary antibody responses to the whole-cell antigen, as well as antibodies in serum and secretions to pertussis toxin (PT) and filamentous haemagglutinin (FHA) were negligible, except for a moderate increase in nasal fluid antibodies to FHA. Unexpectedly, the same vaccinees developed significant rises in nasal and salivary IgA antibodies to meningococcal outer-membrane antigens, whereas corresponding serum IgA and IgG antibodies were unchanged. Thus it appears that mucosal immunisation may induce secretory antibodies with broader specificities than can be found in serum.