Some critical considerations on the serum diagnosis of syphilis

Abstract

In its application to the detection of syphilis antibody the Bordet-Gengou phenomenon of complement fixation has received but little consideration in its quantitative aspect. As will presently be pointed out it is only by respecting the quantitative relations of all reagents concerned that the test becomes reliable and delicate. Even with an adequate quantity of antigen, blood cell suspension and the patient's serum the detection of the antibody by means of complement fixation may or may not be successful according to whether or not appropriate amounts of hemolytic amboceptor and complement are employed. A large excess of either one of these two reagents can prevent the test from revealing the presence of the antibody. While it is easy for a serologist to see why complement should be used in definite and uniform quantity, not every worker seems to be conscious of the disturbing effects which are exerted by an excess of the amboceptor. In view of the overlooking of certain principles of hemolysis by most of the investigators of the present time a brief consideration of this particular subject seems to be advisable. For the sake of convenience I take the example of the antisheep hemolytic amboceptor for illustrating the influence of an excessive amount of the amboceptor upon the phenomenon of complement fixation. The effects exerted by the excessive sensitization is two-fold.