A reverse hemagglutination assay was used to study adherence to human erythrocytes by Escherichia coli H10407, which possesses colonization factor antigen I. Pretreatment of erythrocytes with trypsin, chymotrypsin, papain, protease, and neuraminidase completely abolished attachment reactivity. In addition, the hemagglutination reaction was prevented by the presence of urea and guanidine. In con...

Rubella hemagglutinating (HA) antigen was prepared in BHK-21 tissue as 5% cell suspensions and from unconcentrated and 20x concentrated infected supernatant fluids. In some instances, unconcentrated fluids were treated with Tween 80 and ether; cell suspensions were treated with ether alone. Preparations were tested for HA activity in dextrose-gelatin-Veronal (DGV) buffer solutions; 0.85% NaCl; ...

Infantile gastroenteritis virus antigens in stools were titrated by the immune adherence hemagglutination test. A good correlation was observed between immune adherence hemagglutination titers and electron microscope counts.

A comparison of the direct agglutination test and the indirect hemagglutination test for the detection of blood serum antibodies to Escherichia coli organisms indicated that these serological tests were comparable. In some instances the indirect hemagglutination test provided higher endpoint readings. Preparation of the antigens for the indirect hemagglutination test was more time consuming tha...