COMPARISON OF MURINE NASAL-ASSOCIATED LYMPHOID-TISSUE AND PEYERS-PATCHES

The nasal mucosal is the first sire of contact with inhaled antigens. However, the nature of local immune responses and the role of nasal-as sociated lymphoid tissue (NALT) in those responses have rarely been st udied. To characterize the cells involved in mucosally derived immune responses, NALT and Peyer's patch (PP) cells from normal mice, and mic e immunized intragastrically or intranasally with cholera toxin (CT), were isolated and analyzed. Compared with PP cells, unstimulated NALT cells contained a higher proportion of T-cells. The CD4:CD8 ratio in N ALT cell preparations was less than that observed in PP and more close ly resembled that seen in spleen. Additionally, the total B-cell frequ ency in NALT cell isolates was 20% lower than that observed in PP cell preparations. Although NALT and PP cell isolates contained both matur e B-cells and cells undergoing activation to express surface IgA, unli ke PP, NALT showed no significant frequency of IgA-switched cells, Aft er intranasal immunization with CT, toxin-specific IgA antibody-formin g cells (AFCs) were detected in NALT cell preparations. The numbers of these cells correlated with CT-specific IgA in nasal, but not in gut washes or sera, thus suggesting local nasal production of antigen-spec ific mucosal antibodies. There was no evidence of anti-CT AFCs in NALT or CT-specific antibody in nasal washes after intragastric CT adminis tration. These results support the notion that nasal mucosal antibody production is best achieved via direct stimulation of IgA-committed, N ALT-derived B-cells.