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Biomedical subjects

J M Cavaillon

Publications and source records attributed to J M Cavaillon.

114 records · Page 7Linked to original sources
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[Influence of injection of cortisone acetate on blast transformation and antibody-dependent cell-mediated cytotoxicity in rabbit (author's transl)].

Inhibition of circulating antibody production by steroids has been repeatedly shown in steroid-sensitive animals such as mice or rabbits. It is well known that after a single injection of 5 mg of cortisone acetate, mouse spleen cells loose their ability to be transformed by B cell mitogens such as lipopolysaccharides or Nocardia water soluble mitogen. Therefore it was of interest to study in the rabbit the influence of cortisone on the reactivity of spleen cells to a B cell mitogen (blast transformation and polyclonal strimulation) and their ability to be cytotoxic in the antibody-dependent cell-mediated cytotoxicity assay. Our data demonstrate that the cells which mediate such a cytotoxicity are cortisone-resistant whereas the B lymphocytes--which can be transformed and polyclonally activated by these mitogens--are sensitive to cortisone treatment.

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[Specific blast transformation of rabbit spleen cells induced by a bacterial polysaccharide and inhibitory effect of peripheral blood lymphocytes (author's transl)].

Following immunization with bacteria (i.e. Salmonella johannesburg), rabbit spleen lymphocytes developed a specific blast response when the lymphocytes were stimulated with polysaccharide, the haptenic moiety of lipopolysaccharide. A clear cut dissociation was noted in the blast response induced by polysaccharide compared with those induced by lipopolysaccharide and lipid A. There was no correlation between the magnitude of the cellular responses and that of the antibody response. Moreover, there was less specificity at the cellular level than at the level of antibody secreted by cells. A decrease of 3H-thymidine incorporation was often observed after immunization, at the level of peripheral blood lymphocytes. An inhibitory effect of these cells was shown on the blast response of spleen lymphocytes with polysaccharide. A high blast response to Salmonella polysaccharide which could be observed in some non-immunized rabbits might be related to a natural sensitization of animals with the same or related unknown antigens which could not be recognized by anti-S. johannesburg antibodies.

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Rabbit B spleen lymphocytes and macrophages as accessory cells in T-cell activation by mitogens.

The enhancement of the response of T cells to concanavalin A (ConA) and phtyohaemagglutinin (PHA) by macrophages has been shown in most species, whereas the accessory role of B cells has been only described in studies using human or rabbit lymphocytes. In rabbit, the accessory activity is confined to a subpopulation of B lymphocytes: the majority of B cells have sedimentation velocity of 2.5 to 4 mm/h, whereas the maximum of the accessory activity is found among the B cells, sedimenting with a velocity of 3.5 to 8 mm/h; B cells sedimenting between 1 and 3.5 mm/h have only a very weak accessory activity. Splenic adherent and/or phagocytic spleen cells may contribute additional augmentation of the response of T cells to ConA, since other macrophages (peritoneal and alveolar) are able to increase the ConA response to spleen T cells.

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