The activity of suppressor cells from spleens of mice of varying ages was assessed by their addition to cultures of normal or SRBC immune spleen cells together with a challenge of SRBC. 1-wk and adult spleen cells were highly suppressive of the secondary in vitro antibody response to SRBC. 3-wk spleen cells were less active in suppressing this response. The nature of the suppression and the cha...

We have generated continuously propagatable T lymphocyte clones to study antigen-specific T cell functions. All Ly-2+ clones mediate suppressive activity and secrete a characteristic pattern of polypeptides that differs from Ly-2- T cell clones. Cells of one clone, Cl.Ly23/4, specifically bind glycophorin from sheep erythrocytes (SRBC). After incubation with [35S]methionine, supernate material ...

Female CBA mice, six months old, have been used. Crystalline insulin (Pliva, Zagreb) was injected s.c, 0,25, 0,5, 1 or 1,5 I.U./mouse/day for 10 days. Since the alterations of the immunological functions after various doses of insulin were not essentialy different, we shall present only the data obtained after treatment with 1 I.U. These doses did not cause any mortality from hypoglycemia. The ...

The number of direct (gammaM) hemolytic plaque responses of irradiated mice, repopulated with relatively small and limiting numbers of bone marrow and thymus cells, was increased by the simultaneous immunization with two antigen complexes instead of one. Anti-sheep responses were augmented by the following antigen combinations: SRBC + HRBC, SRBC + BRBC, and SRBC + CRBC. Limiting either thymocyt...

Phorbol myristate acetate (pma) is a potent mitogen for human peripheral blood lymphocytes (PBL) comparable to phytohemagglutinin (PHA) in potency. Inactivation of PHA-responsive lymphocytes by 5'-bromodeoxyuridine and light treatment left the PMA response intact and nice versa. Experiments separating lymphocytes by rosetting with sheep erythrocytes (SRBC) demonstrated that the PMA-responsive l...

A hemolytic plaque assay was developed for the detection of antibody-forming cells to bluetongue virus (BTV). Sheep erythrocytes (SRBC), onto which BTV had been absorbed, served as the indicator of lysis due to the presence of BTV antibody-forming cells. The ratio of BTV to SRBC was found to be critical for optimum hemolytic plaque formation. For routine use, 50 mul of 12% BTV SRBC, 0.1 ml of a...

Studies on birds and mammals indicate that sexual traits may signal superior health because active immunity, like inflammatory responses to infections, is suppressive to the production of androgens that facilitate the expression of these traits. Here we test this possible pathway for honest signaling in a teleost species, Sarotherodon galilaeus, by activating the immune system with sheep red bl...

The role of Igh-linked loci in the generation and expression of T cell help for antibody responses to sheep erythrocytes (SRBC) was investigated. The production of IgM, IgG3, IgG1, IgG2b, and IgG2a antibody to SRBC was shown to be T cell dependent. The Igh-congenic mouse pair CBA/Tufts (Ighj) and CBA.Ighb gave equivalent responses to SRBC. CBA.nude mice (Ighj) supplemented with peripheral T cel...

Rosettes against SRBC were made from normal spleen cells. Although T rosettes tend to dissociate, they could be stabilized with 0.05% sodium azide. A clear separation of nonrosettes, T rosettes, and B rosettes was obtained by subjecting the suspension of splenic rosettes to velocity sedimentation at unit gravity. Each fraction was injected with either normal bone marrow cells or normal thymus c...

A cellfree extract prepared from the spleen cells of C3H mice is capable of suppressing antibody responses to SRBC when extract material is exposed to alloantigens. The observed immunosuppression was attributed to a soluble factor in the extract. This allogeneic suppressive factor (ASF) was detected in extracts prepared from the spleen cells of unirradiated mice as well as those of irradiated m...