Use of an Antiglobulin Plaque Neutralization Test among Group A Arboviruses

Among several infections in mice, both lethal and nonlethal, it was found that an antiglobulin plaque neutralization test was superior to a standard plaque neutralization test for the detection of antibody. In most cases, the antiglobulin plaque neutralization test detected antibody sooner and to higher titer than the standard plaque neutralization test. In one of the nonlethal infections, the antiglobulin plaque neutralization test detected antibody concentrations ranging from 1:80 and 1:1280 where it was otherwise undetectable by a standard plaque neutralization test, complement-fixation test or hemagglutination-inhibition test. In certain hyperimmune sera there was sometimes little difference in the results of the two tests, but absorption of the antisera with viruses revealed significantly higher titers by the antiglobulin plaque neutralization test than the standard plaque neutralization test in the remaining antibody population in at least 2 of 4 sera examined. In addition, infectious virus-antibody complexes which remained after absorption of antibody could be neutralized by the addition of antimouse gamma globulin but not by control fluids.