DETERMINATION OF IMMUNOLOGIC CORRESPONDENCE FOR TAXONOMIC STUDIES BY DENSITOMETRIC SCANNING OF ANTIGEN-ANTIBODY PRECIPITATES IN AGAR-GEL

1. 1. A technique is described which provides for objectively determining relative immunological correspondence among antigens being compared in micro-immunodiffusion tests. 2. 2. The technique is of greatest value in taxonomy for comparing heterogeneous protein systems in which tiny volumes, instability and pigmentation prevent reliable data from being obtained using the standard fluid-system precipitin tests. 3. 3. Relationships among species, established by means of turbidimetric analyses of fluid-system precipitin tests, were confirmed using the densitometric technique. 4. 4. The disadvantages of the technique are the result of the inherent limitations imposed by the diffusion of fluids through a semi-solid media. The test in agar is less sensitive than are the fluid-system systems. It is more concentration dependent. Accurate comparisons of antigens by the densitometric scanning of immunologic precipitates is limited to strongly reacting systems. © 1968.