OVER THE PAST several years, work in our laboratory has focused on studies of the occurrence and characterization of specific antibodies in secretions of the respiratory tract in an attempt to identify their biological significance in immunity.1-7 These studies arose from the need for a simple biological marker of immunity which could identify individuals most likely to resist overt respiratory tract infection with any of a number of pathogens, particularly viruses. The results of these studies suggest that antibody in respiratory secretions is predominantly of the γA-immunoglobulin variety and the presence of such antibody appears to correlate better with resistance to infection than humoral antibody.2,3,6,7
In a series of extremely important experiments, Tomasi et al,8 Chodirker and Tomasi,9 and Tomasi and Zigelbaum10 demonstrated that the particular type of γA-immunoglobulins in external secretions which bathe organs and systems in continuity with the external environment, was of