Biomedical subjects

T Triglia

Publications and source records attributed to T Triglia.

43 records · Page 3Linked to original sources

PubMed1984

A mature myeloid antigen identified on human natural killer cells.

A rat monoclonal antibody (MAb), NIMP-R10, selected for binding to mouse granulocytes was found to identify all mature human peripheral blood neutrophils and a subpopulation of mononuclear cells. By cell sorting experiments the mononuclear cells labelled with NIMP-R10 were shown to be predominantly large granular lymphocytes encompassing most of the natural killer cell activity of peripheral blood cells. NIMP-R10 blocks the complement receptor on mouse myeloid cells, but the MAb was found to have no such biological activity when human cells were examined.

Animals↗

PubMed1984

A novel antigenic cell surface protein associated with T200 is involved in the post-activation stage of human NK cell-mediated lysis.

A monoclonal antibody, 9.1C3, was used to investigate the mechanism of natural killer (NK) cell-mediated lysis. In addition to blocking NK cell function, the antibody blocked antibody-dependent cellular cytotoxicity against the K562 target cell at the effector cell level. The stage at which 9.1C3 antibody inhibited cytolysis was established with a Ca++ pulse technique, whereby it was shown that the antibody inhibited killing at a discrete step after the Ca++-dependent programming for lysis. The 9.1C3 antigen appeared to be associated with the T200 glycoprotein complex. Thus the 66 and 77 Kd proteins detected by 9.1C3 were also precipitated with a monoclonal antibody to T200, and in sequential immunoprecipitations, 9.1C3 antibody removed these bands from immunoprecipitates with antibody to T200. Also, in co-modulation studies, it was found that antibody to T200 co-capped the 9.1C3 antigen but that capping with 9.1C3 antibody did not induce co-modulation of the T200 antigen. Expression of the 9.1C3 and T200 antigens on different cell types, however, was not identical, and the 9.1C3 antibody did not immunoprecipitate high m.w. proteins in the region of 200 Kd. Functionally, in NK cell killing studies, the antibody to T200 used alone did not block but was synergistic with the 9.1C3 antibody. The differential effect of the enzymes pronase and trypsin on the cell surface expression of the 9.1C3 and T200 antigens reflected the ability of these enzymes to inhibit NK cell killing. These data suggest that the 9.1C3 antigen participates in a late event in the cytolytic pathway.

Antibodies, Monoclonal↗

PubMed1984

Anti-idiotype antibodies to the 9.1C3 blocking antibody used to probe the lethal hit stage of NK cell-mediated cytolysis.

We previously described a monoclonal antibody, 9.1C3, which blocked natural killer (NK) cell-mediated cytolysis by acting on effector cells during a late step in the lethal hit stage. The present work describes the production in rabbits of anti-idiotypic (anti-id) antibodies to the 9.1C3 antibody. In addition to reacting specifically with the 9.1C3 antibody, the anti-id antibodies bound strongly to the K562 target cell. The anti-id antibodies blocked killing of K562 targets by NK, antibody-dependent cellular cytotoxicity, and NK-like cells but did not inhibit killing by cytotoxic T lymphocytes (CTL). Pretreatment of cells and washing before assay indicated that blocking occurred at the target cell level. Of particular interest, single cell assays with Percoll-enriched large granular lymphocytes demonstrated that the antibodies caused no reduction in binding. These data are consistent with a model for NK cell-mediated lysis that involves a secondary target cell receptor independent of the primary NK-target cell interaction. The anti-id antibodies immunoprecipitated cell surface proteins of relative m.w. 79K and 62K unreduced, and 94K and 79K reduced from K562 target cells. The development of anti-id antibodies may be a useful procedure to explore the structure and function of cellular receptors involved in NK cell-mediated cytolysis.

Animals↗

PubMed1984

In vitro generation of human activated lymphocyte killer cells: separate precursors and modes of generation of NK-like cells and "anomalous" killer cells.

The activation of human peripheral blood mononuclear cells (PBM) in culture leads to the generation of nonspecific killer cells. These cells, termed activated lymphocyte killer (ALK) cells, can kill fresh tumor cells and tumor cell lines, in addition to the natural killer (NK) cell sensitive target K562. ALK cells have features in common with both T and NK cells, but their nature and origin are unknown. In the present study, it is shown that ALK cells are in fact heterogeneous and can be generated from both large granular lymphocytes with the same phenotype as NK cells and from T cells. Cell populations enriched for NK cells, when cultured with lymphokines, rapidly acquired a T cell phenotype, enhanced cytolytic activity against K562, and the ability to lyse NK-insensitive target cells such as a melanoma cell line LiBr; these ALK cells were described as NK-like cells. On the other hand, of the cloned cells derived from PBM stimulated with irradiated B lymphoblasts and grown in lymphokines, the major proportion of cytolytic T cells (CTC) able to kill the specific stimulator lymphoblasts were also found to kill LiBr but not K562 cells. These ALK cells, which were derived from the same precursors as CTC, were designated anomalous killer (AK) cells. Consistent with this, the presence of the pan T monoclonal antibody UCHT1 from the beginning of mixed cell cultures inhibited the generation of CTC and of the AK-type of ALK cell, which killed melanoma cells, but not the NK type, which killed K562 targets. By contrast, at the effector cell level, the antibodies UCHT1 and OKT8 only blocked specific killing by CTC but did not block the killing of LiBr or of K562 targets by ALK cells. However, at the effector cell level there was additional evidence for the heterogeneity of ALK cells. Thus, monoclonal antibody 9.1C3, which blocks killing by freshly isolated NK cells, also blocked the killing of K562 targets by NK-like cells, but did not block B lymphoblast killing by CTC or melanoma cell killing by AK cells. It is concluded that after mixed lymphocyte culture, the majority of ALK cells measured by the killing of melanoma target cells arise from the same precursors and are under the same influences as classical CTC (AK cells), whereas cells killing K562 targets are derived from NK cells (NK-like cells). Once generated, the AK cells have a different mechanism of killing from both classical CTC and from NK and NK-like cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Antibodies, Monoclonal↗

PubMed1983

A method for in vitro clearance of mycoplasma from human cell lines.

Rapid and reproducible clearance of mycoplasma contaminating human cell lines was achieved using macrophages and antibiotics. Human peripheral blood monocytes were purified by Percoll density gradient centrifugation and allowed to mature into macrophages by 7 days culture in vitro. To the adherent monolayers of macrophages were added the cells to be cleared. Optimal results were obtained with a macrophage to cell concentration of 100:1, together with 200 micrograms/ml of the antibiotics tylosin and lincomycin. The cleared cells were recovered after 7 days of treatment. Monitoring with the Hoechst 33258 stain demonstrated that cells cleared by this method have remained mycoplasma-free for over 6 months. The method is unlikely to cause cell mutation or to introduce mouse viruses and is effective on both adherent and non-adherent cell lines.

Cell Line↗

PubMed1983

Mouse monoclonal antibodies can nonspecifically inhibit the proliferation of human T-cell growth factor-dependent T cells.

A large series of mouse monoclonal antibodies was found to inhibit the proliferation of T-cell growth factor (TCGF)-dependent human T-cell blasts as measured by the incorporation of tritiated thymidine. The specificity of the antibody appeared to be irrelevant for inhibition and two T-cell-specific antibodies did not prevent the absorption of TCGF by treated T cells. It is suggested that the antibodies function by the indirect release of suppressor factors by Fc receptor-bearing TCGF-dependent cells.

Animals↗

PubMed1983

Human natural killer cells, activated lymphocyte killer cells, and monocytes possess similar cytotoxic mechanisms.

The relationship between the killing mechanisms of human natural killer (NK) cells, mitogen- and mixed-lymphocyte-culture-induced activated lymphocyte killer (ALK) cells, and monocytes was investigated with a monoclonal antibody. The IgG2 antibody 9.1C3 was prepared from mice immunized with purified human large granular lymphocytes and selected from clones that inhibited NK cell killing. The 9.1C3 antibody bound to all mononuclear cells but not to granulocytes or K562 cells, and it selectively blocked killing of K562 targets by both NK and ALK cells without affecting the binding of effector to target cells. The antibody blocked killing when present from time zero and it still inhibited partially even when added 1 hr after initiation of the lytic reaction. Killing of Epstein-Barr virus-transformed B lymphoblasts by classical cytotoxic T lymphocytes was not inhibited. Of interest, 9.1C3 did block the killing of K562 target cells by cultured peripheral blood monocytes. Other monoclonal antibodies that bound to monocytes did not block killing, and a nonspecific effect of the antibody on monocytes was excluded. These data suggest that NK cells, ALK cells, and monocytes can kill tumor cell targets by using similar lytic mechanisms.

Animals↗