Immune stimulated regional inflammatory responses mediating lung reactivity in rats

Daily sensitization of SPF BNxWi/Fu rats with ovalbumin (OA) in aerosol during 2-week periods with a 4-week interval resulted after 7 weeks in IgE, IgA and IgG antibodies in serum and bronchial fluid. After cultivation of the regional, axillary, brachial and mediastinal (ABM) lymph node cells, IgE antibodies were found in the culture supernatant. Such antibodies were not found in culture supernatants of spleen and inguinal lymph nodes. Regional formation of IgE antibodies was also noted in the ABM lymph node cell culture supernatants after subcutaneous (s.c.) injections of 100 ng OA in the neck region. When the injections were given in the tail-root region, the inguinal but not the ABM lymph nodes produced the IgE antibodies. The s.c. sensitization induced inconsistent and rather low IgG and no IgA antibody responses. The aerosol but not the s.c. sensitization induced accumulations of mononuclear cells and mucous cells in the lungs. Clinically, the rats sensitized s.c. in the neck region reacted to aerosol and intravenous (i.v.) challenge as early as 1 week after sensitization had started, whereas the animals sensitized in the tail-root regions reacted 7 and 8 weeks after repeated sensitization. The animals sensitized by aerosol showed only weak clinical reactivity after i.v. challenge.