Serologic Specificity of Human Anti-IgA and its Significance in Transfusion

Anti-IgA antibodies detected by a passive hemagglutination assay are either specific for the IgA class or they are of limited specificity. Persons lacking IgA can produce class-specific anti-IgA as a result of parenteral exposure to incompatible IgA globulin in blood and its components. In contrast, persons with normal levels of IgA may produce anti-IgA of limited specificity. Either type of anti-IgA antibodies was present in 86 per cent of anaphylactoid and urticarial transfusion reactions. A majority of these antibodies are of the IgG class.

THE SEROLOGIC SPECIFICITY OF TROPOCOLLAGEN TELOPEPTIDES

Tropocollagen preparations from carp, buffalo fish, rats, calves, sheep, and humans have been studied by electron microscopy and serologic methods. Tropocollagens from each species appeared identical by electron microscopy but they were readily distinguished (except between sheep and calves) by C'-fixation tests with rabbit antisera against the various tropocollagens. Tests with calf tropocollagen antiserum showed no distinction between tropocollagen isolated from different tissues nor between individuals of the same or different strains. The major immunogenic sites in native tropocollagen are the telopeptides, and these are present on both α1- and α2-chains. The C'-fixing activity was lost with heat denaturation of the tropocollagen, but could be recovered in a concentration-dependent process on cooling. The fact that pure and enzyme-treated collagen can provoke serologic reaction implies that collagenous sutures and prostheses used in surgery may lead to sensitization and rejection, a fact which may merit clinical concern.

THE PROBLEM OF SPECIFICITY IN SEROLOGIC DETERMINATION OF HUMAN CHORIONIC GONADOTROPHIN

ABSTRACT Rabbit antisera, prepared against a commercial, highly purified preparation of human chorionic gonadotrophin, have been examined with regard to their serologic specificity. Analyses were carried out using procedures of immunodiffusion and complement fixation. Heterogeneity of the immune system is confirmed, and the distribution and serological relationship of unspecific antigens in urine and serum examined. The effect of various methods on the elimination of unspecific antibodies is shown. The implications of these findings on the immunoassay of human chorionic gonadotrophin in body fluids are discussed.