Nasal immunization with tetanus toxoid increases the subsequent systemic dimeric IgA1 antibody response to intramuscular immunization.

We have investigated the effects of nasal immunization with tetanus toxoid (TT) on the subsequent systemic IgA response. Healthy adult volunteers who had not had a TT boost for at least five years received either an intra-muscular (IM) TT immunization alone (n = 19) or first an intra-nasal and then two weeks later an IM immunization (n = 27). The serum and circulating B cell IgG and IgA1 antibody response to TT were measured. When compared to subjects who received only an IM immunization, those who were nasally primed had increased serum levels of dimeric IgA1 antibodies to TT and an increased number of B cells secreting IgA1 antibodies to TT. These data indicate that mucosal antigen exposure is one of the mechanisms involved in the induction of systemic serum IgA1 response.