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M Cebrián

Publications and source records attributed to M Cebrián.

24 records · Page 2Linked to original sources
PubMed1987

Different functional sites on rIFN-alpha 2 and their relation to the cellular receptor binding site.

Functional domains on the recombinant interferon-alpha 2 (rIFN-alpha 2) molecule, which are involved in antiviral and NK enhancing activities, have been defined by immunochemical mapping with MAb, and their relationship with the IFN cellular receptor binding site has been studied. With 20 different anti-IFN-alpha 2 MAb selected by their binding to 125I-labeled IFN and by immunoprecipitation of the 20 Kd IFN molecule, we have defined three spatially separated epitopes (designated as sites A, B, and C) and two partially overlapping antigenic determinants on the IFN-alpha 2 molecule. Functional relation of IFN-alpha 2 A, B, and C epitopes have been determined by assaying the effect of various anti-IFN MAb on IFN-mediated biologic activities. MAb directed to sites A and B neutralized the antiviral activity of IFN. Furthermore, the MAb specific for site B displayed a neutralizing potency threefold higher than MAb directed to site A. Site B was also involved in the enhancing activity of IFN on NK-mediated cell cytotoxicity, whereas site A was not. MAb directed to site C partially affected the IFN-boosted NK activity but did not neutralize the IFN antiviral activity. Inhibition studies of 125I-IFN binding to human U-937 myelomonocytic cells by anti-IFN MAb demonstrated that MAb directed to site B blocked different IFN biologic functions by preventing its binding to the cellular receptor, whereas MAb directed to sites A and C caused no inhibition and partial inhibition of this binding, respectively.

Antibodies, Monoclonal↗
PubMed1986

VLA-3: a novel polypeptide association within the VLA molecular complex: cell distribution and biochemical characterization.

The family of human T cell activation-associated proteins, named VLA complex, is formed by the molecular association of cell surface glycoproteins of 210, 165, 130 and 80 kDa. In this report, we describe eight different monoclonal antibodies (HP mAb) specific for the 80-kDa polypeptide which preferentially associates with the 165-kDa member. Comparative immunoprecipitation and cell-binding studies demonstrated that the HP mAb recognize an epitope(s) on the 165/80 kDa subset different from those recognized by other anti-VLA mAb previously described. Furthermore, cellular and tissue distribution studies by flow cytometry and peroxidase staining showed that the HP reactivity pattern is different from other VLA specificities. The 165/80-kDa complex defined by HP mAb is present on human thymocytes, peripheral blood lymphocytes as well as on T, B and myelomonocytic cell lines. However, only the 80-kDa subunit was precipitated by HP mAb from activated T lymphocytes. These results suggest that the association between the 165- and 80-kDa subunits diminishes during the activation process, and that the epitopes recognized by the HP mAb are located on the 80-kDa protein. The novel polypeptide association of 165/80 kDa has been termed VLA-3.

Antibodies, Monoclonal↗
PubMedDate not supplied

Levels of dichloro-dyphenyl-trichloroethane (DDT) metabolites in maternal milk and their determinant factors.

To document the levels and the determinants of dichloro-dyphenyl-trichloroethane (DDT) metabolites in maternal milk, we conducted a cohort study of 50 adult females who lived in Mexico City. We measured social and dietary characteristics via interview. Levels of DDT metabolites were determined by gas-liquid chromatography. The mean values (lipid milk basis) were 0.162 ppm p,p'-DDT; 0.138 ppm o,p'-DDT; and 0.594 ppm 2,2(bis)p-chlorophyenyl-1-1-dichloroethylene (DDE). The main determinants of DDT metabolites were maternal age, lifetime lactation, history of living in an agricultural area, and consumption of salted meat and fish. We estimated that 6.0% of the breast-fed babies had daily intakes of DDT above the level of 0.005 mg/kg d recommended by the World Health Organization/Food and Agriculture Organization of the United Nations (WHO/FAO). Health-outcomes research among children is needed, and investigators should design or adjust current surveillance programs.

Adult↗