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Biomedical subjects

N Gross

Publications and source records attributed to N Gross.

67 records · Page 4Linked to original sources
PubMed1978

Rabbit antiserum against Daudi-cell membrane fractions detects cell surface antigens present on subpopulations of human lymphocytes.

An antiserum was produced by immunization of rabbits with membrane preparations of a human lymphoblastoid B cell line, Daudi. After absorption with a human endometrial carcinoma cell line, this antiserum appeared to be specific for antigen(s) present on adult and fetal thymocytes as well as on tonsillar lymphocytes but absent, or present in very small amounts, on normal or phytohemagglutinin- (PHA) stimulated peripheral blood lymphocytes (PBL). When T and B cell-enriched fractions from tonsillar lymphocytes were tested with the anti-Daudi serum, the reactivity was equally distributed in each population. Among 13 human lymphoblastoid cell lines tested, reactivity was demonstrated on three out of four T cell lines, and on four out of nine B cell lines. The positive reacting B cell lines were derived from two African and two American Burkitt lymphomas. The antigen(s) described does not seem to be related either to human Ia-type antigens or to Epstein-Barr virus-associated antigens because these antigens are not present on fetal or adult thymocytes. Reciprocal absorption experiments indicate that this anti-Daudi serum detects the same antigenic structures present on certain subpopulations of T and B lymphocytes.

Absorption↗
PubMed1978

Rabbit antiserum to human thymocyte membranes: specificity for normal and malignant T-lymphocytes.

An antiserum was obtained by immunization of rabbits with human thymocyte membrane fractions. After appropriate absorptions, the antiserum was shown to detect specifically a population of T-cells. When tested by complement-mediated cytotoxicity the antiserum lysed 95% of thymocytes, 65% of normal PBL and 45% of tonsillar lymphocytes. It was also cytotoxic for three different T-cell lines (MOLT-4, CCRF-CEM and CCRF-HSB-2). When peripheral or tonsillar lymphocytes were separated into populations enriched in B- and T-cells, the percentage of cells lysed by the antiserum correlated well with the proportion of E-rosetting cells. Treatment of PBL with the antiserum and complement resulted in an increase of SmIg-positive B-cells in the residual cell fraction, which could no longer form E-rosettes. Treatment of PBL with the antiserum alone completely inhibited the E-rosette formation. The cytotoxic index on PBL from patients with various lymphoid disorders always correlated with the proportion of T-cells as assessed by E-rosette formation. Finally, the absorptive capacity of thymocytes for the antiserum was ten times higher as compared to that of PBL or tonsil cells.

Animals↗
PubMed1977

Genetic effects of photoadducts and photocross-links in the DNA of phage lambda exposed to 360 nm light and tri-methylpsoralen or khellin.

The furocoumarin, 4,5',8-trimethylpsoralen, sensitizes cells and viruses to 360 nm light, producing cross-links and monoadducts in their DNA. The furanochromone khellin is a less effective sensitizing agent than psoralen, but has been found to induce cross-links and adducts in DNA also. The number of cross-links increases as the square of the time of exposure to light. We found that greater fluences were required for khellin than for psoralen, possibly because of the less favorable angle of the distal unsaturated bonds for corss-linking pyrimidines in adjacent base pairs. By adjusting the time of exposure to 360 nm light, lambda phages were damaged with [3H]psoralen and [3H]khellin so as to produce equal numbers of cross-links. These exposures were found to produce 8-times more [3H]khellin than [3H]psoralen adducts in the DNA of the phages. Similar exposures were made with nonradioactive photosensitizers to determine the effectiveness of lambda phages carrying cross-links and monoadducts in producing genetic recombinants. Lambda phage-prophage genetic corsses were performed with psoralen and khellin-damaged phages under repressed conditions in which replication of the damaged DNA was blocked. It was estimated from the results that cross-links were about 20-times more effective than monoadducts for inducing recombination under repressed conditions. In tests on the survival of plaque forming ability on wild type bacteria, it was estimated that cross-links were about 15-times more effective than the adducts. The results support the conclusion that, in homoimmune crosses with psoralen-damaged lambda phages infecting wild type lysogens, more than three-quarters of the induced recombination can be attributed to cross-links rather than to monoadducts.

Binding Sites↗
PubMedDate not supplied

Surface antigenic profile of uveal melanoma lesions analysed with a panel of monoclonal antibodies directed against cutaneous melanoma.

The surface antigenic profile of 10 surgically removed uveal melanoma lesions and 5 conjunctival melanomas was analyzed with a panel of 22 monoclonal antibodies (mAbs) raised against membrane bound cutaneous melanoma-associated antigens (MAA). In addition these lesions were tested for their reactivity with mAbs against MHC class I and II molecules, CD7 (Pan-T) and CD10 (CALLA). The anti-MAA mAbs can be divided into two major groups: first those mAbs detecting markers expressed by the majority of uveal melanomas such as NKI-Beteb, NKI/C3, G7E2, M-2-2-4, Mel-14, G7A5, AMF6, AMF7, Pal M1, Pal M2, Me14/D12. The staining intensity for these mAbs was rather high, ranging in intensity between 70 and 100%. The second group of antibodies includes mAbs detecting markers not or very poorly expressed on ocular melanomas. The anti-ICAM-1 mAb P358 did not react with any of the lesions tested and mAb Muc18 and Muc54 only with one and two out of 15 lesions, respectively. The majority of spindle lesions and mixed type lesions and half of the epitheloid type lesions expressed HLA class I molecules, while HLA class II molecules were found on half of the spindle and epitheloid type lesions and on a small number of mixed cell type lesions. All spindle lesions were found to express the CD10 (CALLA) molecule and less than half of the other type of lesions were stained with an anti CD10 mAb. The melanoma associated ganglioside GD3 was mainly expressed on epitheloid type lesions while GD2 was predominantly expressed on mixed type lesions. In essence, the overall surface phenotype of the uveal melanoma lesions tested, as defined by the panel of mAbs used, differs markedly from the surface phenotype of cutaneous melanoma lesions defined by a very similar antibody panel.

Antibodies, Monoclonal↗
PubMedDate not supplied

Monoclonal antibodies to gamma-interferon treated LAN-1 cells detect modulation of ganglioside GD2 exposure on human neuroblastoma cells.

A panel of 8 new Mabs have been produced against neuroblastoma cells (LAN-1) previously treated with IFN-gamma. All selected Mabs from 2 different fusions have been shown to detect epitopes on the GD2 ganglioside molecules highly expressed on all cells of neural crest origin including neuroblastoma, glioblastoma and melanoma. Our results imply that modulation of GD2 exposure on NB cells is dependent on culture conditions and moreover that IFN-gamma increases the surface expression of GD2 and thereby enhances their immunogenicity.

Antibodies, Monoclonal↗