Detection of Human Reagins with Rat Peritoneal Mast Cells by Histamine Release

Abstract

An immunologically specific method was developed for the detection of reaginic antibodies in sera of allergic individuals. It is based on the determination of histamine release (HR) from rat peritoneal mast cells (RPMC), presensitized with the allergic serum, on challenge with the appropriate allergen. The amount of HR was shown to depend on the concentrations of reagins and allergens. From experiments involving RPMC sensitized with different fractions of allergic serum isolated by chromatography or with appropriate reverse immunosorbent, it was deduced that the bulk of HR was due to antibodies of the IgE class and that about 10% of HR was attributable to antibodies of the IgG type; however, paradoxically, IgG of normal human serum did not have the capacity to sensitize RPMC. Both classes of immunoglobulins present in reaginic serum and capable of sensitizing RPMC were inactivated at 56 °C or with 0.1 M 2-mercaptoethanol. Peritoneal mast cells or a rat, which had been immunized to produce homocytotropic (HCT) antibodies, or RPMC sensitized in vitro with rat HCT antibodies, did not fix human reagins. By contrast, human reagins to two distinct allergens were fixed on the same RPMC preparation by successive sensitization of the cells with the corresponding sera. The cells sensitized with rat HCT antibodies released histamine on challenge with anti-human IgE serum. It is therefore concluded that there exist structural homologies between the groups of human and rat reaginic antibodies which are responsible for fixation on rat RPMC, as well as between the antigenic groups of these two reaginic antibodies capable of crossreacting with anti-human IgE.

Homocytotropic antibodies (IgE) to Neisseria gonorrhoeae in the rat and a cross-reactivity of heterologous gonococcal strains.

“…c HISTAMINE RELEASE FROM MAST CELLS OF ACTIVELY SENSITISED RATS Two rats from each group were selected randomly on days 10, 22, and 35 after immunisation. The cells were harvested from the rats as reported earlier (Vijayanagar et al, 1974). A modified technique of Evans and Thomson (1972) was used to determine the ability of the mast cells from actively sensitised rats to release histamine on challenge with homologous zeolite antigens either GC6-T1 ZA or GC6-T4 ZA.…”

Preferential Synthesis of IgE Reaginic Antibodies in Rats Immunized with Alum-Adsorbed Antigens

“…1, 2, 3, 4) were selected randomly on days 10, 21, and 35 after the initial immunization with OA and DWSR. Cells were harvested from these rats and specific antigen (OA or DWSR) HR was measured as previously re ported [18]. Challenging doses of antigens used in HR tests ranged from 0.03 to 90 /tg.…”