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Updated: Jun 19, 2026

Opsonophagocytic Killing Assay to Assess Immunological Responses Against Bacterial Pathogens
Published on: April 5, 2019
ON THE MECHANISM OF OPSONIN AND BACTERIOTROPIN ACTION : IV. THE ISOELECTRIC POINTS OF CERTAIN SENSITIZED ANTIGENS
M McCutcheon1, S Mudd, M Strumia
1The Henry Phipps Institute and the Department of Pathology of the University of Pennsylvania, Philadelphia.
Abstract:
Sensitization with increasing concentrations of homologous immune serum shifts the isoelectric point of the antigens studied progressively to the alkaline side. Antigens maximally sensitized with rabbit sera have shown isoelectric points of pH 5.6 to 5.8. The globulins precipitated or salted out of the same immune sera have been isoelectric at pH 5.1 to 5.2. The combination of antigen with antibody depends of course upon specific affinities; the surface properties of the sensitized antigen, agglutination and phagocytosis depend primarily upon the properties of the sensitizing serum substances combined with and deposited on the antigen surface.
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