Characterization of a Rabbit Homocytotropic Antibody Responsible for Passive Cutaneous Anaphylactic Reactions with a Short (4-Hour) Latent Period

Abstract

Adult New Zealand rabbits were immunized intraperitoneally with 1·0 μgof ovalbumin (EA) in alumina gel or subcutaneously with 1.5 μg of bovine γ-globulin (BGG) and alumina. Immunizations were repeated at 30 and 60 days and every 2 months thereafter. The rabbit sera were examined for homocytotropic antibody by a 72-hour passive cutaneous anaphylactic (PCA) reaction in rabbit skin. Seven of 20 rabbits immunized with EA and 3 of 9 given BGG developed titers of 1:20 or greater; 2 in each group had titers in excess of 1:200. Rabbit sera with 72-hour PCA titers greater than 1:200 also caused vascular permeability of rabbit skin after a 4-hour latent period. The 4-hour anaphylactic antibody had physical-chemical characteristics similar to the 72-hour PCA antibody. It eluted from DE-52 cellulose with 0.10 m saline, was excluded from Sephadex G-200 between the first and second peak, and appeared in a sucrose density gradient slightly in advance of the bulk of the IgG. Absorption with monospecific antisera to rabbit IgE eliminated both the 4- and 72-hour PCA reactions, but there was little effect from an antibody to rabbit IgG. These findings suggest that the same antibody was responsible for the 4- and 72-hour anaphylactic reactions and that it is rabbit IgE.

Inflammatory mechanisms in the passive cutaneous anaphylactic reaction in the rabbit: evidence that novel mediators are involved

“…There was a heat-resistant component which is consistent with previous observations made with rabbit IgE (Revoltella & Ovary, 1969;Kravis & Zvaifler, 1974a;Stux & Ovary, 1976).…”

“…Male New Zealand White specific pathogen-free rabbits (2.5-3.5kg) were purchased from Froxfield Farm, Hampshire and Hacking and Churchill, Huntingdon, Cambridgeshire. Generation of antiserum for PCA reactions Antiserum for PCA reactions was raised in rabbits according to a schedule which stimulates preferential production of IgE antibodies (Kravis & Zvaifler, 1974a). The antigen (bovine gamma globulin (BGG), 1.5#gper rabbit) was dissolved in saline, mixed with two volumes of aluminium hydroxide, washed twice and injected subcutaneously in a volume of 1 ml.…”

“…In rabbits, IgE antibody can be raised by immunisation with a low dose (ptg quantities) of antigen mixed with aluminium hydroxide. This procedure produces maximum IgE titres after 120 days (Kravis & Zvaifler, 1974a) and a detailed study of the antibody was made by Stux & Ovary (1976). However, in this and other studies, no attempts were made to investigate which mediators were generated following antigen challenge, other than establishing that antihistamines were weak inhibitors.…”

Heterogeneity of Rabbit Homologous Skin Sensitizing Antibodies: IgE and a New Subclass IgG_a

“…Shorter sensitization periods, e.g. 2-8 h, although still eliciting the PCA reactions, as shown by others [36], gave only 3-50% of the total activity that the serum or a purified fraction were capable of developing under optimal sensitization periods, the purifield material being relatively more effective with short sensitization periods.…”