Antigenic Analysis of Lepromin by Agar-diffusion1

The identification and the establishing of relationships among the various antigens associated with the mycobacteria have been the subject of innumerable investigations. The classical serologic technqiues of complement-fixation, agglutination, and precipitation have been employed in this endeavor by many investigators. Information has also been provided by sensitizing both normal and tanned erythrocytes with bacillary components of mycobacteria and subsequently testing these antigen preparations with appropriate antisera (1,5,6). Thus far the application of these techniques to the serologic study of leprosy has not been highly rewarding, due to the difficulties encountered in obtaining suitable antigenic material (8). Despite this, Olmos Castro and Bonatti (7) have devised a microflocculation test which depends on chloroform extracts of lepromatous tissue as the antigen. Although others .may have undertaken similar investigations, there is little evidence of this in the literature. A relatively new method for studying antigenic relationships takes advantage of the independent diffusion and precipitation of antigens and antiDodies in gels (8). This technique has proved suitable for examining mixed serologic systems, i.e., systems composed of multiple antigens, or antibodies, or both. Recently several investigators (2, 9,10) have applied this procedure for the analysis of mycobacterial antigens. The present report describes the results of preliminary experiments designed to determine the practicability of employing the agar diffusion , . technique in the study of antigens present in lepromin, and to relate these antigens if possible to those found in old tuberculin.