Indirect hemagglutination with Mycoplasma antigens: effects of pH on antigen sensitization of tanned fresh and formalinized sheep erythrocytes.

An investigation of the influence of different factors affecting the sensitivity of the indirect hemagglutination test has been performed with antigens of four mycoplasmas isolated from sheep or goat. Tanned erythrocytes of sheep, fresh and formalinized, were sensitized with the above antigens. It was demonstrated that, with formalinized erythrocytes, the sensitivity was increased by 50 to 100 times when the sensitization was done at a low pH level. The pH level was unimportant for sensitizing fresh erythrocytes. The greatest sensitivity of the indirect hemagglutination test was obtained with fresh rather than formalinized erythrocytes. Three different types of antigens were used, and the most suitable antigen was found to be the supernatant fluid from an ultrasonically treated centrifuged Mycoplasma suspension.