Incomplete Antibodies in Experimental Brucella Infection by the Late

It was shown by Wiener (1944) that some human a,nti-Rh sera contained incomplete antibodies which combined with but did not agglutinate the corresponding red cells. They appeared to be more avid than agglutinating antibodies, so that, if the two kinds of antibody co-existed in the same serum, the incomplete or blocking antibody might account for failure of agglutination or for a zone of inhibition in the tubes containing the greatest amount of serum. Inhibition of this nature has long been known to occur with the sera of some patients and animals suffering from brucella infection. Grimtts (1947), Cox & Kutner (1950), Renoux (1950), Schuhardt, Woodfin & Knolle (1951) and Jones & Wilson (1951) all found blocking antibodies to titres ranging from 1/10 to 1/128 in the sera of persons or of cattle suspected of brucella infection, these antibodies being absent from normal sera or present in low titres only. Incomplete antibodies have also been demonstrated by the antiglobulin technique of Coombs, Mourant & Race (1945a, 6). Jones & Wilson (1951) and Wilson & Merrifield (1951) applied this method to the diagnosis of brucella infections and found that the Coombs test revealed significant antibody titres in a considerable number of brucella cases in which the sera were negative to the ordinary agglutination test. Inhibition zones were also eliminated by the Coombs test. Ferris, Stevenson & Lewis (1953) found the test of greater value than the agglutination test for the detection of subclinical or past infection in abattoir workers. CorticeUi (1952), Wagner & Kuhns (1953), Clapp (1953), Fey & Biirki (1954) and Brahic, Tamalet, Tamalet & Madet (1955) all report on the examination of sera from persons suspected of brucella infection in which Coombs antibodies were present in the absence of ordinary agglutinins or were present to higher titres. Of special interest is the work of Hall & Manion (1953) who compared the titres of agglutinins, blocking antibodies and Coombs antibodies in eighty persons. They found no correlation between agglutinins and blocking antibodies, but found that the Coombs method increased sensitivity without destroying specificity, the increase in titre being often fourfold. The object of the present work was to investigate the appearance of incomplete antibodies in experimentally infected guinea-pigs.