Immunogenicity studies of foot and mouth disease vaccines at different concentrations of antigen and saponin.

Frenkel-type monovalent O1 and C vaccines were tested for immunogenicity under field conditions, in a large cattle farm. Both vaccines were applied in four dilutions, to furnish different concentrations of antigen, and each dilution was tested with 4 and 8 mg/dose levels of saponin, and without adjuvant. In adult multivaccinated already one eight of the standard bovine dose of both preparations developed a satisfactory booster effect, and presence or absence of the adjuvant played little role.

Determination of antigen content and effectiveness of foor-and-mouth disease vaccines.

The following paragraphs are in reality the conclusion of a communication which was not presented at the symposium owing to Dr Czelleng's absence. Taking the place of his colleague, Dr Sólyom gave a brief account of the complement fixation test in the estimation of immunity against foot-and-mouth disease. The test conditions are improved by using a standardized complement; this method allows to meausre very precisely the amount of antigen used for the production of vaccine.

Studies on the correct quantitative relations of antigen components in mono-, bi- and trivalent foot-and-mouth disease vaccine preparations.

Waldmann and frenkel type mono-, bi- and trivalent FMD vaccines, with different quantitative relations of the antigen components, were prepared and tested by the E, K and S index methods. Potency tests in adult mice showed that the antigen components of the bivalent vaccines are usually synergistic, but a 47-57% excess of antigen "O1" over the other two types is always required for a similar immunogenic action (E index value). For the same reason, the "O1" content of the trivalent vaccine should be as high as the total quantity of its other two components.