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Biomedical subjects

E Gazit

Publications and source records attributed to E Gazit.

At least 145 records · Page 8Linked to original sources
PubMed1983

Characterization of human umbilical cord blood lymphocyte subsets fractionated on immobilized peanut agglutinin.

Human cord blood mononuclear cells from single donors were separated on minicolumns of peanut agglutinin (PNA) coupled to Sepharose beads to yield two fractions: unbound cells (PNA-, 78%) that were eluted with phosphate buffered saline, and bound cells (PNA+, 22%) eluted with 0.2 M D-galactose. The total yield was 86% and the cells were fully viable. There was no enrichment for macrophages or for surface immunoglobulin positive (B) cells in either the PNA+ or PNA- subset. Only 26% of the PNA+ lymphocytes formed rosettes with sheep red blood cells, in contrast to 53% of the PNA- lymphocytes. The response of the PNA+ cells to mitogens and allogeneic stimulation was considerably lower than that of the PNA- cells, while that of the latter was higher than the response of the unseparated cells. The average ratios of response of the PNA+ to PNA- cells were 0.25 for PHA, 0.20 for concanavalin A, 0.15 for pokeweed mitogen, and 0.15 In the mixed lymphocyte reaction. when tested with monoclonal antibodies to lymphocyte surface markers, it was found that the PNA+ fraction was depleted of mature T cells and enriched in Ia positive cells. Our data show that the low reactivity of human cord blood mononuclear cells may be ascribed to the presence of a subpopulation of lymphocytes which are immunologically immature. They also provide further evidence that in humans the PNA receptor is a marker for immature T or B lymphocytes.

Cell Separation↗
PubMed1983

Granulocyte specific cytotoxic antibodies in pregnancy and multitransfused sera.

The myeloid cell line K562 was used to screen for specific antibodies in sera obtained from pregnant women and multitransfused patients. The alloantisera thus procured reacted with random granulocytes in a pattern suggestive of a polymorphic system. Some antibodies were found to react only in the cold. A simple reproducible method for the simultaneous separation of granulocytes and lymphocytes for microcytotoxicity is described.

Antibody Specificity↗
PubMed1983

Familial palindromic rheumatism: a possible association with HLA.

Palindromic rheumatism is very rare in children. The familial occurrence of the disease has been only briefly reported previously. A family is described here in which the mother and her 3 children suffered from typical palindromic rheumatism, which ran a benign course. All 4 members were seronegative and the HLA types of the children were identical. The HLA genotype of the mother was HLA A2, Cw4, Bw41, Bw6, DR5, MT2/Aw32, CX, Bw44, Bw4, DR1, MT1. HLA DR5 has previously been found to be associated with juvenile rheumatoid arthritis, while DR1 in Jews is significantly associated with adult-onset rheumatoid arthritis. DR5 was shared by the mother and her 3 children. The presence of the antigen DR5 in this sibship suggests that palindromic rheumatism may be a variant of juvenile rheumatoid arthritis with a relatively late onset and a more benign course. Tissue typing of patients with palindromic rheumatism may give a clue to prognosis. The patients' youth and the familial involvement, with identical HLA characteristics, are the outstanding features of this family.

Adolescent↗
PubMed1982

Changes in the expression of HLA and beta 2-microglobulin by cultured lymphoid cells.

Changes in the expression of HLA and beta 2-microglobulin (beta 2-m) antigens by cultured human lymphoid cell lines were investigated. HLA expression was assayed by indirect trace binding radioimmunoassay (RIA) with monoclonal antibodies and by determining sensitivity to complement-dependent lysis by alloantisera. Lymphoid cells in culture were found to undergo changes in the expression of HLA and beta 2-m antigens characterized by decreased membrane expression of these antigens at high cell densities or after a prolonged period of cultivation. The decreased expression of HLA and beta 2-m antigens apparently is due neither to a masking phenomenon nor to a lack of nutrients or an accumulation of metabolites in the culture media but is perhaps mediated by a cell-to-cell contact mechanism. Human interferon was found to enhance the expression of HLA and beta 2-m, apparently overriding the effects on major histocompatibility complex (MHC) expression induced by cell density.

Antibodies, Monoclonal↗
PubMed1982

Enzymatic chemical modification of human amniotic membrane and skin as a means for the preparation of biological dressing.

A non-antigenic biological dressing of amniotic membrane and skin was prepared by treatment with the enzyme ficin and dialdehyde starch. The dressing was tested in experimental animals for the coverage of full-thickness skin defects. The healing process was studied, as well as the durability of the biological dressing. Testing for flexibility, adherence and antigenicity, there was no change in the ficin-treated dressing when used even after being stored for a period of up to 2 years. The enzyme treatment did not result in a superior biological dressing.

Amnion↗
PubMed1982

Association of HLA-Aw31 and HLA-DR1 with adult rheumatoid arthritis.

Forty-nine Israeli Jewish patients with rheumatoid arthritis (RA) were studied for their HLA A, B, C, DR antigen frequency. A significant increase in HLA Aw31 and HLA DR1 was observed (p less than 5.10(-5) and p less than 5.10(-3) respectively). 45% of Aw31 positive patients were sero-negative for rheumatoid factor, while most HLA DR1 positive individuals were seropositive. DR5 was found to be significantly decreased (p less than 5.10(-4)). Contrary to previous reports, DRw4 was found to be within the range of antigen frequency of the controls (34.7% vs. 32%). It is suggested that in our population of patients Aw31 and DR1 and not DR4 are highly associated with adult onset of RA.

Aged↗
PubMed1982

Antigenic determinants detected on adenoid lymphocytes.

This study was undertaken to detect the antigenic determinants expressed by adenoid lymphocytes. For this purpose, adenoid and peripheral blood lymphocytes obtained from the same patient were subsequently tested with human and hetero antisera. The research was based upon microlymphocytotoxicity where the various lymphocyte subsets were incubated with the antiserum and complement. The reactions were scored by the dye exclusion technique. The results indicated that: 1) compared with peripheral blood, the expression of the major histocompatibility gene products is enhanced by adenoid lymphocytes; 2) adenoid T lymphocytes express DRw antigens. These antigens were thought to be restricted to B lymphocytes and macrophages but have later been detected in T lymphocytes activated in vitro. Thus, lymphocytes derived from hypertrophied adenoids may simulate a culture activated in vivo; 3) because of their higher sensitivity to antibodies and complement-mediated cell lysis, adenoid lymphocytes may be useful in detecting minor histocompatibility gene products and differentiation antigens. It is concluded that adenoids represent a highly active lymphoid organ probably actively participating in the host's immunological defence mechanism.

Adenoids↗
PubMed1982

Alloantisera detect HLA-A-B-C and non-HLA differentiation antigens on human thymocytes.

Human thymocytes (THY) were examined for the expression of HLA-A,B,C antigens on their cell surface by using tissue typing alloantisera in the microcytotoxicity assay. Approximately 80% of the total THY population demonstrated antibody-mediated, C-dependent lysis with several alloantisera for each HLA-A,B,C specificity. The HLA phenotype of THY was verified by HLA typing autologous peripheral blood lymphocytes (PBL) from the thymus donor. Thymus tissue and PBL were obtained from cardiac surgical patients ranging in age from 3 mo to 12 yr. The capacity of THY to absorb HLA alloantibody was also demonstrated. Cross-absorption studies performed on PBL and THY by using HLA typing sera produced two important findings: 1) HLA typing sera that are devoid of non-HLA THY-specific antibody can be used to HLA type THY and 2) selected non-HLA sera from multiparous women, and selected HLA typing sera absorbed with PRL or platelets can be used to detect THY differentiation antigens. Taken together, cytotoxicity data, absorption capacities, cross-absorption studies, and statistical analysis indicate that HLA-A,B,C alloantigens and non-HLA polymorphic differentiation antigens detected by alloantisera are co-expressed on the cell surface of the majority of human THY.

Antibody Specificity↗
PubMed1981

HLA antigens in Jews with pemphigus vulgaris.

The association of HLA antigens with pemphigus in Jewish patients of various ethnic origins was investigated. Of 45 Ashkenazi patients, 31 (68.6%) had A26 (p less than 10(-5) and 32 (7175) had BW38 ( less than 10(-5)0. Among the 11 non-Ashkenazi patients, 7 (63.6%) had A26 and only 1 had BW38. The question whether the antigen A26 or BW38 is linked with the disease is discussed. Our findings may suggest that the primary association of pemphigus is with A26. This association may be stronger in Jewish male patients than in females. In view of the recent literature and our results it may be presumed that pemphigus in Jews is associated with antigens of Loci A and DR. No differences between pemphigus vulgaris and pemphigus erythematosus were observed.

Adult↗