Transmission of IgA and IgG monoclonal antibodies to mucosal fluids following intranasal or parenteral delivery

Background: The efficacy by which passive antibodies can reach the lungs co uld be important for the outcome of immunotherapy of respiratory pulmonary infections. We examined how transmission to a number of mucosal sites is af fected by the route of inoculation. Methods: Transmission of newly raised I gA class Mabs against mycobacterial surface antigens to saliva, lung or vag inal lavage, bile and serum of BALB/c mice was compared with existing IgG M abs. ELISA was used for testing body fluids obtained 1-24h after intranasal or intravenous inoculation and 1-7 days following back-pack tumour growth of hybridomas. Results: Intranasal inoculation resulted in a rapid rise and high levels of both IgA and IgG class Mabs in lung lavage. In contrast, fo llowing intravenous Mab injection or back-pack tumour growth of hybridoma c ells, effective lung transmission was observed for the IgG1 and IgG2b MAbs, but not for the IgA Mabs. The secretory component was acquired by the tran smitted IgA MAbs in the mucosal fluids, but not in the serum. Nevertheless, the time course of mucosal IgA antibody levels was similar to that of the tested IgG Mabs. Furthermore, the relative proportion of transmission to sa liva and bile varied between individual Mabs indicating a role of tissue-sp ecific, immunoglobulin class-unrelated mechanisms. Conclusions: Intranasal, rather than parenteral inoculation of mice is required for the efficient d elivery of IgA antibodies against respiratory pulmonary pathogens. Interest ingly, IgA-secretory component complexing of intranasally applied Mabs did not significantly influence their persistence in the lungs. Copyright (C) 2 000 S. Karger AG, Basel.