Lectin binding patterns in rat nasal-associated lymphoid tissue (NALT) andthe influence of various types of lectin on particle uptake in NALT

We investigated the binding of four types of lectin to follicle-associated epithelium overlying the nasal-associated lymphoid tissue (NALT) of rats in order to identify M-cell specific surface markers and to determine the inf luence of lectin administration to NALT on the uptake of a particulate anti gen. The NALT tissues were incubated with a panel of four types of lectin c onjugated to horseradish peroxidase (HRP). Ulex europaeus-1 (UEA-1) and Dol ichos biflorus (DBA) lectin stained the surface of M-cells and goblet cells . Uniform staining by Triticum vulgaris (WGA) was detected in the M-cells, ciliated cells and goblet cells. In contrast, staining of Griffonia simplic ifolia I isolectin-B-4 (GSI-B-4) was almost exclusively M-cell specific. Th e administration of M-cell specific lectin (GS I-B-4) to NALT suppressed th e uptake of baker's yeast particles administered later, whereas the non-spe cific one (UEA-1) had no influence on the uptake. These results indicate th at GS I-B-4 is a useful marker for the identification of rat NALT M-cells a nd that such a specific expression of surface glycoconjugates by M-cells ma y permit the targeting of vaccines and drugs to the antigen sampling sites of the nose. It also appears possible to block the uptake of pathogens by a n administration of M-cell specific lectin to NALT.