Relationship between Histocompatibility (H-2) Genotype and Immune Responsiveness to Low Doses of Ovalbumin in the Mouse

Abstract

Abstract A relationship has been recently described between the histocompatibility (H2) type of inbred strains of mice (1) and their immune responsiveness to low doses of hapten conjugates of bovine γ globulin (2,3). Several H-2k strains, as well as A/HeJ mice (H-2a) responded vigorously to immunization with repeated 0.1- to 1.0-µg doses of the conjugates, whereas H-2b, H-2d and H-2q strains failed to respond detectably. The present results indicate that the immune responsiveness to low doses of ovalbumin, or hapten conjugates of it, has nearly an opposite distribution. A single injection of 0.1 µg of ovalbumin in Al (OH)3 gel adjuvant induced intense and persistent primary antibody responses in H-2b and H-2q mice, whereas A/He mice (H-2a) and H-2k strains failed to respond. Young adult female mice were used for immunization. Inbred animals from several different strains, described in the text, were obtained from the Jackson Laboratory, Bar Harbor, Maine. Mice from two random-bred Swiss Webster strains —CFW (Carworth Farms, New City, N.Y.) and SW-55 (from Rio de Janeiro)—were also used for immunization. CFW mice were used as recipients for skin tests. The proteins used as immunogens or in hapten conjugates were bovine serum albumin (BSA, fraction V) and five times crystallized chicken’s ovalbumin (OVA), both from Pentex, Inc. (Kankakee, Ill). Benzylpenieilloyl (BPO) conjugates of BSA and OVA, respectively BPO37BSA and BPO6OVA, were prepared by reaction with crystalline potassium benzylpenicillin (Bristol Laboratories, Syracuse, N. Y.) in saline at alkaline pH as described elsewhere (3). An A1 (OH)3 gel was used as adjuvant (3). All mice were immunized by i.p. injection of immunogen-adjuvant mixtures in 0.5-rnl volumes, both for primary and secondary doses. At intervals after immunization, 0.2-ml samples of blood were collected by orbital bleeding, diluted in saline, and the diluted serum was separated and stored frozen until assayed. Groups of three to six mice of each strain were used; their sera were either pooled for assays or tested individually. Antibody responses were assayed by passive cutaneous anaphylaetie (PCA) reactions in CFW recipient mice, as previously described (3,4). Sensitization periods of both 2 hr and 48 hr were used to assay respectively IgG1 and reaginie (IgE-like) antibodies. Prior studies (5,6) indicate that these two tests, i.e., 2-hr PCA and 48-hr PCA, detect two distinct types of mouse immunoglobulins. Usually four sites per recipient mouse were used and each antiserum dilution was tested in at least three recipient mice.