Biomedical subjects

Z Steplewski

Publications and source records attributed to Z Steplewski.

At least 181 records · Page 10Linked to original sources

PubMed1979

Colorectal carcinoma antigens detected by hybridoma antibodies.

Hybridoma cells which secrete colorectal carcinoma-specific antibodies have been produced and used to study the antigenic structure of these tumor cells. Nineteen antibodies have been studied in detail, and 15 of these are colorectal carcinoma specific. Only two antibodies reactive with carcinoembryonic antigen (CEA) have been discovered and five other antibodies that react with distinct epitopes on the cell surface have been defined. Several antigens with distinct molecular characteristics have been shown to exist by use of hybridoma antibodies. Six hybridoma antibodies have been shown to mediate antibody-dependent cell-mediated cytotoxicity (ADCC).

Animals↗

PubMed1979

Colorectal carcinoma-specific antigen: detection by means of monoclonal antibodies.

Fusion of P3 X 63 Ag8 mouse myeloma cells with splenocytes obtained from mice immunized with cells derived from human colorectal carcinomas resulted in the production of antibody-secreting hybridomas. Two hybridomas (1083-17 and 1116-56) and their clones secreted antibodies binding specifically to human colorectal carcinoma cells either grown in culture or obtained from patients, but did not bind to normal colonic mucosa or other normal and malignant human cells. The binding specificity was consistent in three assays: radioimmunoassay, mixed hemadsorption, and immunofluorescence. Adsorption of these antibodies to colorectal carcinoma cell lines totally eliminated their specific binding.

Antibodies, Neoplasm↗

PubMed1978

Epstein-Barr virus in somatic cell hybrids between mouse cells and human nasopharyngeal carcinoma cells.

Somatic cell hybrids between mouse cells and cells derived directly from NPC biopsies were produced in order to study the association of the Epstein-Barr virus (EBV) genome and the expression of Epstein-Barr nuclear antigen (EBNA) with the human chromosome(s). All attempts to correlate the presence of EBV-DNA and the expression of EBNA with the presence of a particular human chromosome(s) showed that the segregation of EBV-DNA or of EBNA and human chromosomes was dysconcordant. The data, therefore, suggest that in the hybrids studied the presence of EBA-DNA is not determined by the presence of a specific human chromosome.

Animals↗

PubMed1978

Study of antibodies against human melanoma produced by somatic cell hybrids.

We fused spleen lymphocytes obtained from mice immunized against a human melanoma cell line and melanoma-mouse hybrid cells with the P3 X 63 Ag8 mouse myeloma in order to produce hybrids secreting antibodies against a human melanoma. Antibodies secreted by individual hybrids were tested for their reaction with a panel of human melanoma, colorectal carcinoma, and normal cells in an indirect radioimmunoassay, and they displayed different specificities and crossreactivities. Some reacted only with melanomas, whereas others crossreacted with normal human or human colorectal carcinoma cells. By analysis of competitive binding of mixtures of monoclonal antibodies, it was possible to delineate different epitopes on melanomas. Hybrids growing in nude mice and producing antimelanoma antibody suppressed growth of melanoma tumors.

Animals↗

PubMed1977

A new approach in specific, active immunotherapy.

A vaccinia virus-lysed autochthonous tumor cell vaccine (vaccinia oncolysate) is introduced as a new specific, active immunotherapeutic agent against human cancer. Mouse experiments showed the vaccine to be a safe and potent immune mechanism stimulator. Human experimentation was undertaken in the knowledge of relative safety of the components of the vaccine, i.e. vaccinia vaccine and lysed, autochthonous tumor cells. Vaccine-treated patients had advanced metastatic cancer but reacted to one or more common recall antigen skin tests. None of the 13 patients had untoward responses; 7/13 patients had classic delayed hypersensitivity reactions at the vaccine injection sites; and 2/7 patients with injection site reactions had significant reduction in tumor burden. These results indicate that this vaccine is a specific, active immune mechanism stimulator, and may prove to be a useful therapeutic agent in the treatment of human cancer.

Animals↗

PubMed1977

Alteration of cell surfaces with increased tumorigenicity.

A comparison of four mouse tumorigenic cell lines derived from transformed peritoneal macrophages is reported. Tumorigenicity of various cell concentration inocula was compared with their saturation densities, agglutinability by Con A, and their surface morphologies as revealed by SEM. It is shown that increase in tumorigenicity after repeated passage through syngeneic mice is associated with changes in their growth characteristics, Con A agglutinability, and correlates with surface changes observed by SEM. The results show that after repeated transfer of transformed cells in syngeneic mice the cells become more tumorigenic, have a higher degree of agglutinability, and show progressive changes of their surface morphology.

Animals↗

PubMed1976

Time sequence and morphological evaluations of cells fused by polyethylene glycol 6000(1).

Mouse L cells (clone 1D) were fused with polyethylene glycol (PEG). The fusion sequence was determined by using sequential light microscopy of the same group of cells, scanning electron microscopy (SEM),transmission electron microscopy, and freeze-etching. The cells were found to fuse only 1 min after PEG had been washed off at small localized areas. Larger fusion images were found after 3 min. Intramembrane particles were observed to have a tendency to aggregate after PEG treatment, but a direct correlation of this activity with the fusion process could not be made. No pathological changes were noted at longer times after PEG removal, except for the extensive widening of the rough-surfaced endoplasmic reticulum (RER) in some cells. It is proposed that fusion does not occur if apposing cells have many microvilli at the area of apparent contact.

Animals↗

PubMed1976