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G Lespinats

Publications and source records attributed to G Lespinats.

60 records · Page 4Linked to original sources
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MHC class I antigen expression and alterations induced by rIFN gamma in tumor hybrid cell immunogenicity.

Hybridization of a poorly immunogenic tumor cell with an allogeneic cell was performed in order to improve tumor immune response; several variants derived from one hybrid tumor cell were studied. We compared the immunogenicity of these variants and their allogeneic and syngeneic class I antigen expression before and after IFN gamma treatment. Allogeneic class I antigens were weakly expressed in all variants; IFN treatment enhanced their expression similarly in both immunogenic and nonimmunogenic variants. Syngeneic class I antigen expression differed among variants: IFN treatment induced changes in their expression which corresponded to a posttranscriptional event and which could, at least partly, explain the modifications observed in their immunogenicity.

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Induction of suppressor cells in mice by cyclophosphamide.

The injection of a single sublethal dose of cyclophosphamide (CY) into adult C3H/He mice induced splenic atrophy followed by considerable hypertrophy. During the phase of splenomegaly, the in vitro reactivity of spleen cells to the mitogens phytohaemagglutin and lipopolysaccharide was drastically decreased. Furthermore, the spleen cell population from CY-treated mice contained suppressor cells capable of inhibiting the in vitro reactivity of normal lymphocytes to these mitogens. After the removal of adherent cells, the suppressive activity was completely absent from the remaining fraction. The suppressive activity was also abolished after treatment of spleen cells with anti-immunoglobulin antiserum plus complement (C). After treatment with anti-Thy 1-2 antiserum plus C, the suppressive activity was not modified. Nude mice, B mice, young and old NZB mice, also developed suppressor cells with similar functional characteristics when treated with CY. However, in Nude mice the suppressor cells were not adherent and did not bear surface Ig. After fractionation of spleen cells by velocity sedimentation, the suppressive activity was detected in the fastest fraction with a velocity over 5 mm/h.

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PubMedDate not supplied

[Suppressive cells induced by cyclophosphamide in the spleen of C3H mice].

The spleen cell population of C3H/He mice injected with a single sublethal dose of cyclophosphamide (CY) was analysed. An initial atrophy was followed by a considerable hypertrophy and a progressive return to normal. During the phase of spleen atrophy, both B and T cell compartments were depleted. During regeneration, the percentage of Ig+ cells increased rapidly, and at the peak of splenomegaly, the percentage of Ig+ cells was high while no Thy1-2+ cells were detectable. The peculiar points of histology were disappearance of normal T and B compartments, substituted by a layer of lymphoid cells. During the phase of splenectomegaly, the in vitro reactivity of spleen cells to the mitogens PHA and LPS was drastically decreased. Furthermore, the spleen cell population from CY treated mice contained suppressor cells, capable of inhibiting the in vitro reactivity of normal lymphocytes to these mitogens and the multiplication of tumour cells in culture. These cells were adherent, Ig+, Thy1-2- cells. They developed in CY treated T deprived mice. After velocity sedimentation the suppressive activity was detected in the 6 mm/h fraction.

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