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F Sanchez-Madrid

Publications and source records attributed to F Sanchez-Madrid.

44 records · Page 3Linked to original sources
PubMed1982

Three distinct antigens associated with human T-lymphocyte-mediated cytolysis: LFA-1, LFA-2, and LFA-3.

Monoclonal antibodies were prepared to anti-HLA-DR cytolytic T lymphocytes (CTLs) and screened for inhibition of CTL-mediated killing. Binding of monoclonal antibodies to four types of molecules, LFA-1, LFA-2, LFA-3, and HLA-DR, inhibited killing, suggesting that these molecules participate in the CTL-target cell interaction. The antigens were characterized by immunoprecipitation, crosslinking, NaDodSO4/polyacrylamide gel electrophoresis, and immunofluorescence flow cytometry. The LFA-1 antigen contains alpha and beta polypeptide chains of Mr 177,000 and 95,000 that are noncovalently associated in an alpha 1 beta 1 structure. It is present on both B and T lymphocytes and marks subpopulations that differ in quantitative expression. Human LFA-1 appears to be the homologue of mouse LFA-1. Human LFA-2 is of Mr 49,000 with a minor component of Mr 36,000. It is expressed on CTL lines but not on a B-cell line and in peripheral blood preferentially on T lymphocytes. Human LFA-3 is of Mr 60,000 and is expressed on both B and T lymphocytes.

Animals↗
PubMed1982

Monoclonal antibodies specific for rat IgG1, IgG2a, and IgG2b subclasses, and kappa chain monotypic and allotypic determinants: reagents for use with rat monoclonal antibodies.

Mouse monoclonal antibodies to rat IgG were obtained by fusion of immune SJL mouse spleen cells to NSI myeloma cells. Seven monoclonal antibodies have been labeled with 125I and studied as to specificity and avidity by using a panel of rat monoclonal antibodies both as inhibitors and target antigens in soft well plate and indirect cell binding assays. All MAb were selected for high avidity of 4 X 10(7) to greater than or equal to 2 X 10(9) M-1. Four MAb were subclass-specific. RG11/39, RG7/1, and RG7/11 were absolutely specific for the Fc' region of IgG1, IgG2a, and IgG2b, respectively. RG9/6 showed specificity for the Fab' region of IgG2a but crossreacted with lower avidity with IgG2c. Three MAb reacted with rat kappa chains. RG7/9 defined a monotypic (common) kappa chain determinant. RG11/15 and RG7/7 were specific for allelic kappa 1a and kappa 1b determinants, respectively. The monotypic and kappa 1a allotypic determinants are topographically separated. The antibodies can be used as screening reagents in indirect cell binding assays. They have sensitivity similar to affinity-purified rabbit anti-rat IgG and more defined specificity. They do not crossreact with mouse or human IgG, making them particularly suitable companion reagents for rat anti-mouse or anti-human MAb. One Mab, RG7/7, strongly crossreacts with Syrian hamster IgG.

Animals↗
PubMed1981

The acidic proteins of eukaryotic ribosomes. A comparative study.

The acidic proteins extracted by 0.4 M NH4Cl and 50% ethanol from ribosomes from Saccharomyces cerevisiae, wheat germ, Artemia salina, Drosophila melanogaster, rat liver and rabbit reticulocytes have been studied comparatively in several structural and functional aspects. All the species studied have in the ribosome two strongly acidic proteins with pI values not greater than pH 4.5., which appear to be monophosphorylated in the case of S. cerevisiae, A.Salina, D. melanogaster and wheat germ. Rat liver proteins are multiphosphorylated, as possibly are those from reticulocytes. The molecular weight of these acidic proteins as determined by SDS electrophoresis ranges from around 13,500 to 17,000 and, except in the case of yeast, of which both proteins have the same molecular weight, the size of the two proteins in the other species differs by approx. 1,000-2,000. In general, the size of the proteins increases with the evolutionary position of the organism, as seems to be the case with the degree of phosphorylation. From an immunological point of view the ribosomal acid proteins of eukaryotic cells are partically related, since antisera against yeast protein cross-react with proteins from wheat germ, rat liver and reticulocytes. Bacterial proteins L7 and L12 are very weakly recognized by the anti-yeast sera. Anti-bacterial acidic proteins do not cross-react with any of the protein from the species studied. The proteins from all the species studied are functional equivalents and can reconstitute the activity of particles of S. cerevisiae deprived of their acidic proteins.

Animals↗
PubMed1980

Recovery of pure ribosomal proteins from stained gels. A fast method of purification of active proteins.

A simple technique has been developed for eluting ribosomal proteins from stained gels in the presence of an acetic acid solution. The ribosomal proteins are then separated from the dye by anion-exchange chromatography under dissociating conditions. Ribosomal proteins purified by these methods give total cross-reaction with proteins obtained by standard procedures, when tested by immunodiffusion against their corresponding antibodies, and show the same electrophoretic mobility as standard proteins in bidimensional polyacrylamide gel systems. Ribosomal proteins L7/L12, recovered from stained gels and purified by these methods, are able to reconstitute the elongation-factor-G-dependent GTPase activity of ribosomal particles deprived of these proteins. Radioactive protein L1, recovered in the same way, is incorporated into a total reconstituted 50-S subunit, competing with an excess of standard L1 present in the pool of total proteins from 50-S subunits used for reconstitution. These results suggest that bidimensional electrophoresis can be considered an alternative system of purification of active proteins from complex mixtures.

Chromatography, Ion Exchange↗