Immune response in the lungs following oral immunization with bacterial lysates of respiratory pathogens.
We have investigated the local immune response of the BALB/c mouse respiratory tract after oral immunization with a bacterial lysate of seven common respiratory pathogens. After two immunization on five consecutive days, we examined the immunoglobulin (immunoglobulin G [IgG], IgM, and IgA) secretion rates of cells isolated from the lungs and compared them with those of spleen cells of orally immunized and nonimmunized animals by using a new test system based on time-resolved fluorescence. The procedure followed the principle of the classical ELISPOT test with nitrocellulose-bottomed microtiter plates, but europium (Eu3+)-linked streptavidin rather than enzyme-conjugated streptavidin was used, with the advantage of quantifying secreted immunoglobulins instead of detecting single antibody-secreting cells. Lymphocytes isolated from the lungs of treated animals revealed significant increases in total and antigen-specific IgA synthesis compared with the rates of the controls, whereas IgG and IgM production rates showed no remarkable differences. In addition, the sera of treated mice revealed higher antigen-specific IgA titers but not increased IgM and IgG levels. We conclude that priming the gut-associated lymphoid tissue with bacterial antigens of pneumotropic microorganisms can elicit an enhanced IgA response in a distant mucosal effector site, such as the respiratory tract, according to the concept of a common mucosa-associated immune system.
D000276:Adjuvants, Immunologic; D000284:Administration, Oral; D000818:Animals; D000907:Antibodies, Bacterial / Q000032:analysis / Q000096:biosynthesis*; D001428:Bacterial Vaccines / Q000008:administration & dosage / Q000276:immunology*; D005260:Female; D015200:Fluoroimmunoassay; D006193:Haemophilus influenzae / Q000276:immunology; D007711:Klebsiella pneumoniae / Q000276:immunology; D008168:Lung / Q000276:immunology* / Q000382:microbiology; D051379:Mice; D008807:Mice, Inbred BALB C; D001936:Moraxella catarrhalis / Q000276:immunology; D012141:Respiratory Tract Infections / Q000276:immunology; D013211:Staphylococcus aureus / Q000276:immunology; D013296:Streptococcus pneumoniae / Q000276:immunology; D013297:Streptococcus pyogenes / Q000276:immunology
D000276:Adjuvants, Immunologic; D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines; C078795:LW 50020