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C Neauport-Sautes

Publications and source records attributed to C Neauport-Sautes.

At least 19 recordsLinked to original sources
PubMed1984

Isolation and partial characterization of messenger RNA, from murine T cell hybrids, coding for suppressive immunoglobulin G-binding factor.

Poly A RNA has been isolated from a murine T cell hybridoma ( T2D4 ) that spontaneously secretes suppressive immunoglobulin G-binding factor ( IgGBF ). Translation products, obtained from a rabbit reticulocyte lysate translation system and after injection into Xenopus laevis oocytes, contain material with the biologic activity, the affinity, and the m.w. of murine IgGBF ; it suppresses secondary in vitro IgG antibody production in a dose-dependent fashion. The suppressive factor binds to IgG but not to IgM immunoadsorbents and, after mild NaDodSO4 treatment, dissociates in NaDodSO4 polyacrylamide gels into two peaks at 78 and 40 kD. Translation products from two non- IgGBF -secreting cell lines (BW-5147, a T lymphoma line, and A9, a fibroblast cell line) fail to exert any suppressive activity. On sucrose gradients, the RNA responsible for the biologic activity was found in one major peak located at 11S. IgGBF synthesized in a cellfree translation system by using poly A RNA and sucrose gradient fractions was also characterized by immunoprecipitation with Fc fragments of [35S]methionine-labeled proteins. On NaDodSO4 polyacrylamide gels, it migrates in one peak located at 37 kD. We conclude that IgGBF is coded for by 11S poly A RNA and that no post-translational modifications (other than proteolytic cleavage) are necessary to obtain a biologically active factor with Ig-binding properties.

Animals↗
PubMed1983

Isotype regulation of antibody production: T-cell hybrids can be selectively induced to produce IgG1 and IgG2 subclass-specific suppressive immunoglobulin-binding factors.

T2D4, a T-cell hybrid, spontaneously secretes suppressive immunoglobulin factor(s); when incubated with purified monoclonal mouse immunoglobulins, this hybrid produces high levels of immunoglobulin-binding factors specific for the subclass of the inducing immunoglobulin. Thus, we were able to induce the production of IgG1- or IgG2-specific inhibitory factors by the same T2D4 T-cell hybrid. These subclass-specific suppressive factors bind selectively to the IgG1 or IgG2 subclasses and inhibit specifically the secretion of antibodies of the corresponding subclass. Our results favor a model of negative regulation of isotype expression in which a given isotype triggers suppressor mechanism(s) specifically inhibiting its production.

Animals↗
PubMed1980

Public H-2 specificities are target determinants for alloreactive cytotoxic T lymphocytes.

The specificity of the cross-killing exerted by cytotoxic T lymphocytes (CTL's) generated against H-2 region products was investigated in a 51Cr release assay on a panel of target cells from a number of different H-2 haplotypes. Their pattern of reaction shows that: (1) The target cells, expressing public specificities (H-2.28, H-2.1, H-2.3 or H-2.8) which should, theoretically, be recognized by the CTL's were killed, while those expressing no public specificities, recognized according to the H-2 chart by the CTL's were not killed. (2) The CTL's generated against the H-2.28 specificity expressed on the D region products cross react with target cells expressing this specificity in their K region products and vice versa. The same phenomenon was observed with the H-2.1 specificity. These results provide evidence that public specificities are targets for CTL's. Antiserum reacting against the public specificity recognized by the CTL's was found to block the cross-killing, however, to the same extent as antisera directed against any specificity (private or public) expressed on the same molecule as the target determinant. Finally both the inhibition studies using anti-H-2 antisera and the direct cytotoxic assays showed that the public specificities of the H-2.28 family carried by the H-2.D and H-2.L molecules were recognized by different subpopulations of CTL's.

Animals↗
PubMed1980

Interferon enhances the expression of Fc gamma receptors.

Murine T2D4 cells derived from a T cell hybrid line were incubated with partially purified or electrophoretically pure mouse interferon and tested for the expression of Fc gamma R as assessed by a) counting the number of cells forming rosettes with IgG-sensitized sheep erythrocytes, and b) incubating the cells with heat-aggregated rabbit IgG and then determining either the number of cells stained with fluorescein conjugated goat anti-rabbit IgG or the extent of labeling by using radioactive iodinated staphylococcus protein A. Although interferon induced a rapid increase in Fc gamma R expression on the Fc gamma R-positive T2D4 cells, it did not induce either Fc gamma R on the Fc gamma R negative BW5147 cells or Fc gamma R on either cell line. Human leukocyte interferon enhanced the expression of Fc gamma R on human Burkitt cells (Daudi) but did not affect the expression of Fc gamma R on mouse cells. We suggest that interferon may influence several effector functions of the immune system by modulating Fc receptor expression.

Animals↗
PubMed1980

Multiple CTL subsets generated by H-2.L locus products stimulation: evidence for an antigenic determinant private to H-2.Ld.

Analysis of the fine specificity of CTL subpopulations raised by an H-2.L locus products stimulation (H-2dm2 anti-H-2d) was performed by absorption experiments by using monolayers of macrophages of H-2m, H-2q, H-2b, and H-2k haplotypes. The results show the existence of four CTL subsets. The pattern of reactivity of three of them could be correlated with that of antibodies present in H-2dm2 anti-H-2d antisera (anti-H-2.64, anti-H-2.65, and anti-H-2.Kk). The fourth CTL subset reacted with a specificity unique to H-2.Ld molecules (a private specificity?), absent on cells from H-2m, H-2q, H-2b, and H-2k haplotypes, and undescribed as yet by serologic methods. These data support the hypothesis that the H-2.L locus products are comparable in their antigenic properties to those of the H-2.K and H-2.D loci.

Absorption↗
PubMed1979

Association between H-2 and vaccinia virus-induced antigens on the surface of infected cells.

The relationship between H-2 molecules and vaccinia virus-induced antigens on the surface of H-2d infected cells was investigated by the differential redistribution method and by the blocking capacity of monospecific anti-H-2 sera on an anti-vaccinia cell-mediated cytotoxicity (CMC). Capping of either H-2K or H-2D molecules upon addition of monospecific and anti-H-2 sera was followed by the complete redistribution of viral antigens, suggesting the formation, on the cel membrane, of complexes of H-2K, H-2D molecules and vaccinia virus-induced antigens. However, not all H-2 molecules were involved in this association since i) free H-2K and H-2D molecules still moved independently on the cell surface, and ii) capping of vaccinia virus-induced antigens failed to induce the redistribution of all the H-2K and H-2D molecules. In addition, either monospecific anti-H-2K or anti-H-2D antiserum was found to exert potent blocking activity on anti-vaccinia CMC, indicating also a close topographical relationship between H-2K, H-2D molecules and vaccinia virus-induced antigens.

Animals↗
PubMed1978

H-2.28, an alloantigenic marker allelic to H-2.1, is expressed on all three known types of H-2 molecules.

Each allele at the K or D region of the H-2 complex produces two kinds of "allelic" or mutually exclusive antigenic characteristics: its unique private specificity and a public specificity(ies) of either the H-2.28 or H-2.1 family. The private specificities of the K and D regions are expressed on H-2K and H-2D molecules, respectively. The D region produces another molecule, H-2L, which lacks the H-2K and H-2D private specificity but exhibits the H-2.28 or H-2.1 specificity. We analyzed the expression of the H-2.28 determinants on H-2K, H-2D, and H-2L molecules. When an antiserum against H-2.28 is used to sensitize cells where it can react with only H-2K molecules or H-2D molecules, by subsequent elution antibodies against H-2.28 are recovered that can also react with H-2L molecules. Hence, determinants reactive with antibodies against H-2.28 are present on H-2L as well as on H-2K and H-2D molecules. The expression of the H-2.28/H-2.1 polymorphism on all three known types of H-2 molecules, without some obvious relation to the private specificities, suggests that the antigenic determinants of these two kinds of allelic systems (private in contrast to H-2.28/H-2.1) may be controlled by separate genes, even when they are expressed on the same molecule.

Animals↗
PubMed1978

Characterization of suppressive immunoglobulin-binding factor (IBF). III. Biochemical and immunochemical characteristics of IBF produced by activated T cells.

The biochemical characteristics of immunoglobulin binding factor produced by activated cells (ATC) were investigated. For this purpose, supernatants of ATC were purified by affinity chromatography on insolubilized IgG and the eluted material was iodinated (125I), treated with mercaptoethanol; and run on SDS polyacrylamide gels. The radioactivity was found in two peaks corresponding to m.w. of 38,000 d and 18,000 d. This result extends and confirms our previous findings that IBF produced by ATC is identical to IBF produced by L-5178-Y internally labeled thymoma cells. The effect of various pH, temperatures, and proteolytic and glycolytic enzymes on the binding properties of 3H-leucine-or H-fucose-labeled IBF to IgG and on the polyacrylamide gel profiles was also studied. By all these criteria, IBF appeared to be a glycoprotein in which the presence of the 38,000 to 40,000 d chain is necessary for the binding to IgG. In the attempt to study the relationships between IBF and I-region products, purified IBF produced by ATC was incubated with anti-Ia immunoadsorbent, and the eluted material was iodinated and run on gels. The 38,000 d and 18,000 d chains characteristic of IBF were found to be specifically retained on the relevant immunoadsorbent. These data favor the hypothesis that IBF bears or is associated with Ia determinants.

Animals↗
PubMed1977

The private specificity H-2.4 and the public specificity H-2.28 of the D region are expressed on two independent polypeptide chains.

The antigenic specificities H-2.4 (private) and H-2.28 (public) in the H-2a haplotype are controlled by the D region of H-2 as defined by the available recombinants. In previous studies we have demonstrated by the antibody-induced redistribution method that the antisera against these specificities contain antibodies against at least two different polypeptide chains. We here report the results of the indirect immunoprecipitation of radiolabeled antigens after solubilization with Nonidet-P40. The antisera against the two specificities precipitated from such extracts two different and independent polypeptide chains, indicating that the products of the D region, as presently defined, comprise at least two different molecules. The molecular weight of both chains is approximately 45 000, which is similar to other molecules bearing private H-2 antigenic specificities. Consequently, the chromosomal segment presently defined by recombination studies as the D region, must contain another locus, controlling the second polypeptide chain which is detectable by anti-H-2.28 antisera, besides the H-2D locus which controls the polypeptide chain bearing the private specificity H-2.4 as well as most of the public specificities.

Animals↗