Induction of intestinal rotavirus-specific antibodies in respiratory, but not gut, lymphoid tissues following mucosal immunization of mice with inactivated rotavirus

Intranasal (i.n.), but not oral, immunization of mice with inactivated rotavirus induces protection against challenge. To understand the mechanisms by which i.n. immunization with inactivated rotavirus evokes protective immunity, we examined the site of rotavirus-specific B cell activation and the origins of intestinal IgA-secreting B cells following i.n. inoculation of mice with inactivated rhesus rotavirus. We found that (1) i.n., but not oral, inoculation induced partial protection after challenge; (2) i.n., but not oral, inoculation induced production of rotavirus-specific IgM, IgA, and IgG by intestinal lymphoid tissues; and (3) after i.n. inoculation, nasal-associated lymphoid tissues (NALT) and bronchial lymph nodes (BLN) were the sites of initial production of rotavirus-specific antibodies. These studies indicate that after inoculation with inactivated rotavirus, virus-specific effector B cells may be more easily activated in respiratory, compared to intestinal, lymphoid tissues. Additional studies are needed to determine if these observations are due to fundamental differences in the microenvironment of HALT and BLN compared to Peyer's patches or are a function of the anatomic differences between the respiratory and the gastrointestinal tracts. (C) 2001 Elsevier Science.