SPECIFIC AGGLUTINATION OF TREPONEMA PALLIDUM BY SERA FROM RABBITS AND HUMAN BEINGS WITH TREPONEMAL INFECTIONS

Abstract

A method was described for the preparation of T. pallidum suspensions that are suitable for specific agglutination studies and can be stored at 4[degree]C for months without loss of agglutinability. Such suspensions were shown to react with 2 distinct antibodies in the serum of syphilitic animals and man: Wassermann antibody and a specific treponeme agglutinin. It was demonstrated that the agglutination of treponemes by specific treponeme agglutinin is enhanced by heat treatment or aging of the suspension, and inhibited by a divalent cation, probably Ca++, normally present in serum. This inhibition was overcome by the use of a chelat-ing agent, ethylenediamine tetraacetate. These findings were utilized to devise a simple agglutination test for the diagnosis of treponeme infections that is very sensitive and highly specific. This test was carried out with 430 human sera, and a comparison was made of the results of the agglutination, treponemal immobilization, and standard serological tests on these sera. The agglutination test appears to have a specificity comparable to the treponemal immobilization test and considerably greater than the standard serological tests.