The anti-globulin technique applied to the detection of non-agglutinating antibody against Salmonella typhi O in human sera

Detection of Q fever antibodies in whey by the anti-globulin sensitization test and other techniques

1. Samples of whey from individual cows and herds infected with R. burneti and from uninfected cows and herds have been tested for R. burneti antibodies.

2. The haemolytic complement-fixation test, the conglutinating complement-absorption test, the direct agglutination test and the anti-globulin sensitization test were compared for sensitivity in detecting whey antibody.

3. The direct agglutination test was generally more sensitive than either of the complement-fixation tests, particularly when it was enhanced by centrifugation of the sensitized rickettsiae. The anti-globulin sensitization test, however, gave the highest titres andit appeared to be specific.

4. The practical application of these techniques and certain theoretical considerations are discussed.

The effect of including anti-Ig sera in the haemagglutination inhibition test for Mycoplasma gallisepticum

Addition of anti-immunoglobulin M (anti-IgM), G (anti-IgG) and A (anti-IgA) sera to the haemagglutination-inhibition (HI) test (anti-Ig HI test) for Mycoplasma gallisepticum resulted in 2- to 8-fold increases in the HI titres. On investigating the anti-Ig HI reaction using IgM and IgG antibodies separated by affinity chromatography, it was confirmed that, in the enhanced HI titres, specificity existed between the chicken Ig classes having antibody activity and the antisera used in the test. Four days after inoculation of M. gallisepticum, the anti-Ig HI reaction was markedly enhanced by anti-IgM antiserum in the intravenously inoculated chickens and by anti-IgA serum in the nasally inoculated chickens. Ten days after inoculation of M. gallisepticum marked enhancement of the reaction was produced by anti-IgG serum in both intravenously and nasally inoculated chickens, but the enhancement of the anti-Ig HI reaction diminished from the second week after inoculation.

The determination of specific IgA-antibodies to Yersinia enterocolitica and their role in enteric infections and their complications

Specific serum IgA-antibodies, mainly produced in the lymphoid tissue of the gastrointestinal tract (GALT) might exhibit some special characteristics deviating from IgM- and IgG-antibodies: they do not agglutinate nor fix complement. They cannot be determined by usual routine antibody techniques; indirect methods must be used. An antiglobulin-assay was used in an extensive investigation over a two-year period on sera from 8,445 patients to determine IgA-antibodies specific to Yersinia enterocolitica, serotype 3. Y. enterocolitica agglutinins were found in 965 patients, 508 of them with significant titres of greater than or equal to 80. 347 of the 2,111 patients with low titres (10 to 40) had a significantly elevated amount of IgA antibodies. The diagnoses of the IgA-positive patients fell into three groups: acute infections, acute reactive complicatory inflammations, mainly arthritis, chronic inflammatory connective tissue diseases. The IgA-antibody pattern was: In early samples from patients with acute enteric infections they might be the only antibodies present following, largely, during the course of the disease the agglutinating IgM and IgG antibodies, except in patients with long-lasting or chronic complications where IgA antibodies were elevated. It is concluded that determination of specific antibodies of IgA class in cases of Y. enterocolitica infections is an important diagnostic test and, moreover, of prognostic value in the evaluation of chronicity.