Search PubMed⌕ Search

Biomedical subjects

K T Brunner

Publications and source records attributed to K T Brunner.

At least 19 recordsLinked to original sources
PubMed1984

Functional activity in vivo of effector T cell populations. II. Anti-tumor activity exhibited by syngeneic anti-MoMULV-specific cytolytic T cell clones.

The functional activity in vivo of murine tumor-specific cytolytic T lymphocyte populations and clones was studied. Tumor cell destruction induced after the i.v. injection of cytolytic effector cells was quantitated by monitoring the elimination of 131IUdR-labeled tumor cells in the peritoneal cavity by using whole-body counting techniques. Mixed leukocyte-tumor cell cultures were established by using spleen cells from C57BL/6 regressor mice that had rejected an intramuscular tumor induced by the injection of MSV-MoMuLV virus. This effector cell population was observed to eliminate syngeneic MoMuLV-induced tumor cells in a dose-dependent manner. Treatment of the effector cell population with monoclonal anti-Lyt-2 antibodies plus complement totally abrogated their ability to induce tumor cell destruction in the peritoneal cavity. MSV-MoMuLV-specific Lyt-2+ cytolytic T cell clones derived by micro-manipulation of T lymphocyte-tumor cell conjugates were also tested for functional activity in vivo. Several clones induced a rapid, specific elimination of 131I-labeled MBL-2 tumor cells from the peritoneal cavity after i.v. injection, whereas others were inactive. Both active and inactive clones were highly cytolytic and secreted MAF/IFN-gamma lymphokines. In contrast to previous results obtained in a tumor allograft model, the MSV-MoMuLV-specific cytolytic T cell clones that were active in vivo did not proliferate in vitro in response to stimulation with irradiated tumor cells plus filler spleen cells in the absence of an added source of interleukin 2.

Animals↗
PubMed1984

Interleukin 2 enhancement of lymphokine secretion by T lymphocytes: analysis of established clones and primary limiting dilution microcultures.

The effect of exogenous interleukin 2 (IL 2) on lymphokine production by T lymphocytes was examined in two systems: the secretion of macrophage-activating factor (MAF) and interferon (IFN) by cloned long-term T cell lines, and a limiting dilution system for estimating the frequency of precursors of MAF-secreting cells in normal spleen. An IL 2-containing, MAF- and IFN-free supernatant from the EL-4 thymoma (EL-4 SN) significantly enhanced release of MAF and IFN by mitogen- or antigen-stimulated, cytolytic or noncytolytic T lymphocyte clones directed against alloantigens or Moloney leukemia virus-associated antigens. Highly purified IL 2 produced equivalent enhancement as EL-4 SN in cultures of alloreactive clones stimulated with concanavalin A. Kinetics experiments showed that EL-4 SN increased both the rate and duration of MAF release by T cell clones. EL-4 SN also increased MAF production when added during restimulation of limiting dilution cultures of positively selected Lyt-2+ and Lyt-2- C57BL/6 splenic T lymphocytes activated against DBA/2 alloantigens. This enhancement resulted in a threefold increase in the apparent precursor frequency of MAF-secreting cells among Lyt-2+ lymphocytes, but did not affect the frequency among Lyt-2- cells. Additional analysis indicated that average MAF production in cultures of Lyt-2-+ cells was sixfold lower than in cultures of Lyt-2- cells, and hence that EL-4 SN allowed detection of a significant proportion of Lyt-2+ cell cultures secreting low levels of MAF. Under these improved conditions, the MAF assay detected the majority of responding Lyt-2+ and Lyt-2- lymphocytes.

Animals↗
PubMed1982

Functional activity in vivo of effector T cell populations. I. Antitumor activity exhibited by allogeneic mixed leukocyte culture cells.

The in vivo activity of murine cytolytic T lymphocyte-containing effector cell populations generated in vitro was studied in a tumor allograft model system by monitoring the elimination of 131I-IUdR-labeled tumor cells with whole-body counting techniques. Mice were irradiated sublethally and 16 hr later 131I-labeled tumor cells were injected either subcutaneously or i.p. Simultaneously, graded doses of various effector cell populations were injected i.v. and the mice were counted daily to assess the potential elimination of the radiolabeled tumor cells. Thus, allogeneic 2 degrees mixed leukocyte culture cells were observed to eliminate allogeneic but not syngeneic tumor cells in a dose-dependent manner, with as few as 0.2 x 10(6) effector cells causing significant destruction of 2 x 10(6) allogeneic tumor cells. The protective effect of the mixed leukocyte culture cells was considerably reduced when Lyt-2+-bearing lymphocytes were eliminated by treatment with monoclonal antibody plus complement. In additional experiments, Lyt-2+ lymphocytes positively selected by enrichment on antibody-coated petri dishes gave efficient protection, in the absence of Lyt-2- cells. Surprisingly, when several different cloned, specific, long-term allogeneic cytolytic T cells lines were injected either i.p. of i.v., tumor cell destruction was observed only after i.p. injection.

Animals↗
PubMed1982

Production of macrophage-activating factor by T lymphocyte clones and correlation with other lymphokine activities.

The production of macrophage-activating factor (MAF) by antigen-stimulated murine T lymphocyte clones has been compared with their cytolytic function and release of other lymphokines. MAF activity was measured by the capacity of peptone-induced peritoneal exudate cells or bone marrow-derived macrophages to lyse 51Cr-labeled tumor cells after incubation with supernatant from the stimulated T cells and a nonactivating, amplifying dose of lipopolysaccharide. Of 72 clones generated against H-2, MIs, H-Y, or Moloney leukemia virus-associated antigens, 68 were found to produce detectable quantities of MAF. Release of MAF by clones 1) occurred within 1 to 12 hr of exposure to antigen, 2) required stimulation with cells of the relevant antigenic specificity, and 3) could also be induced by concanavalin A, indicating that the cloned cells were the source of the activity. The capacity of a clone to produce MAF was independent of its antigenic specificity, cytolytic activity, or ability to produce interleukin 2 or granulocyte-macrophage colony-stimulating activity. In contrast, production of interferon and MAF was not dissociated for any of the clones tested.

Animals↗
PubMed1981

Quantitation and clonal isolation of cytolytic T lymphocyte precursors selectively infiltrating murine sarcoma virus-induced tumors.

A limiting dilution mixed leukocyte-tumor cell microculture system was used to quantitate cytolytic T lymphocytes and their precursors (CTL-P), which infiltrate tumors induced by injection of Moloney sarcoma-leukemia virus (MSV-MoLV) complex into C57BL/6 mice. Leukocyte populations obtained from tumors collected on day 10 after virus injection were found to contain significantly higher frequencies of operationally defined (tumor-specific) CTL-P than either peripheral blood leukocytes (PBL) or spleen cells from the same animals. When these frequencies were normalized according to the content of Lyt-2+ T cells in each tissue, average CTL-P frequencies were found to be 1/9 in tumor-infiltrating cells vs. 1/41 in PBL. These results directly demonstrate selective accumulation of CTL-P in the tumor mass. A number of clonal isolates obtained from tumor-infiltrating leukocyte populations were expanded and studied for cytolytic activity and specificity. Of 11 isolates, 10 were found to have high cytolytic activity, leading to 50% lysis of the syngeneic MoLV-derived tumor target cells in 3.5 h at lymphocyte:target cell ratios ranging from 0.5:1 to 3.2:1. Furthermore, five randomly selected clones showed H-2 restriction by their selective lytic activity against MoLV-derived syngeneic MBL-2 target cells and their lack of activity against either MoLV-derived allogeneic (LSTRA) tumor cells or against syngeneic (EL4) or allogeneic (P815) target cells unrelated to MoLV.

Animals↗
PubMed1981

Inhibition of cytolytic T lymphocyte clones reactive with Moloney leukemia virus-associated antigens by monoclonal antibodies: a direct approach to the study of H-2 restriction.

H-2 restriction in cytolytic T lymphocyte (CTL)-mediated lysis of syngeneic murine Moloney leukemia virus (MoLV)-induced tumor cells was studied at the clonal level by testing the inhibitory effect of monoclonal anti-H-2 antibodies on the lytic interaction between CTL clones and target cells. Large numbers of MoLV-specific CTL clones were generated by placing limiting numbers of C57BL/6 regressor (responder) spleen cells into micro-mixed leukocyte-tumor cell cultures. The clonal CTL populations thus obtained were split into 5 aliquots and tested for lytic activity in the presence (or absence) of 1 of 3 monoclonal antibodies or of an anti-whole H-2b haplotype antiserum. Two of the monoclonal antibodies were directed against H-2Db and one against H-2Kb determinants. Specificity of these reagents had been verified by demonstrating inhibition of lysis by CTL populations directed against H-2Db and H-2Kb alloantigens. In 44 of a total of 51 clones tested, results showed selective inhibition by the anti-H-2Db (and the anti-whole haplotype) reagents, and lack of inhibition by the anti-H-2Kb antibody., Of the remaining 7 clones, none was inhibited by the anti-H-2Db antibody, and 3 were inhibited by the anti-whole haplotype antiserum. These studies show that the recognition of MoLV-associated antigens by the majority of CTL clones was restricted to the H-2Db region, and that there exists limited heterogeneity in the H-2 restriction of such clones.

Animals↗
PubMed1980

Antigenic specificity of the cytolytic T lymphocyte response to murine sarcoma virus-induced tumors. III. Characterization of cytolytic T lymphocyte clones specific for Moloney leukemia virus-associated cell surface antigens.

Cytolytic T lymphocyte (CTL) clones specific for Moloney leukemia virus (MoLV)-derived tumor cells were generated by placing limiting numbers of C57BL/6 responder cells into mixed leukocyte-tumor cell microcultures. Under appropriate conditions (presence of stimulating tumor cells, accessory cells, and T cell growth factor), such cloned CTL could readily be expanded to provide large numbers of homogeneous, highly cytolytic CTL populations for further characterization. Using four target-cell types, three specificity patterns were observed: one reactive with the syngeneic MoLV-derived tumor only, one cross-reactive with an allogeneic MoLV-derived tumor, and one cross-reactive with normal allogeneic cells. Subclones derived from these three types of clones exhibited a high degree of stability in terms of lytic activity and specificity over a 4-mo period of observation. Three clones analyzed by flow cytofluorometry using monoclonal antibodies were all found to be of the Lyt-1+2+ phenotype. Furthermore, lysis of target cells by all of six clones tested was inhibited by anti-H-2Db (but not by anti-H-2Kb) monoclonal antibodies, demonstrating H-2Db-restriction at the clonal level.

Animals↗
PubMed1980

Generation of cytolytic T lymphocytes in vitro. XI. Accessory cell requirement in secondary responses to particulate alloantigen.

The non-T accessory cell requirement for cytolytic T lymphocyte (CTL) generation in vitro was studied in a system which makes use of particulate membrane preparations as a source of alloantigen, and spleen cells from alloimmune mice as a source of responding cells. It is shown that removal of nylon-adherent cells from the responding cell population strongly reduced CTL generation, whereas direct removal of Ig+, phagocytic or plastic-adherent cells had no effect. The CTL response of the nylon-nonadherent cell population could be reconstituted by the addition of normal spleen cells, which by themselves do not generate CTL in response to particulate alloantigen. The accessory cell function of normal spleen cells was not affected by depletion of T cells or of phagocytic cells, but was sensitive to gamma-irradiation (1000 rd). The system thus demonstrates the requirement for a nylon-adherent accessory cell population in the secondary CTL response to particulate alloantigens which does not exhibit the typical characteristics of T cells, B cells or macrophages.

Animals↗
PubMed1979

Cell-mediated immunity to antigens associated with murine sarcoma virus-induced tumors: augmentation of cytolytic T lymphocyte activity by successive specific and nonspecific stimulation in vitro.

It has been shown previously that lymphoid cells from mice which have rejected a tumor induced by the Moloney sarcoma virus-leukemia virus (MSV-MLV) complex develop high levels of specific H-2-restricted cytolytic T lymphocyte (CTL) activity after in vitro stimulation with syngeneic, irradiated MLV-induced lymphoma cells in mixed leukocyte-tumor cell cultures (MLTC). Attempts to further increase lytic activity by restimulating long-term MLTC cells with syngeneic, irradiated lymphoma cells have met but with limited success. This report shows that, in contrast to the lack of increased activity observed after specific stimulation with lymphoma cells, nonspecific stimulation of long-term MLTC cells either with supernatants from secondary mixed leukocyte cultures (2 degrees MLC SN) or with supernatants from concanavalin A-stimulated spleen cells leads, on a per cell basis, to a further 5 to 10-fold increase in CTL activity. The stimulatory activity of 2 degrees MLC SN is due to a factor(s) of apparent mol. wt. of 25,000 to 40,000. The activity of the CTL populations formed under these conditions is at least 100-fold higher against syngeneic as compared to allogeneic MLV-induced or unrelated tumor cells.

Animals↗
PubMed1979

Generation of cytolytic T lymphocytes in vitro. XII. Detection of memory CTL precursors in peripheral blood of alloimmune mice.

The memory cytolytic T lymphocyte (CTL) response of mice was studied in vitro using peripheral blood leucocytes (PBL) of donors previously immunized with allogeneic cells as responding cells, and particulate alloantigen for stimulation. It is shown that alloimmune but not normal PBL respond to particulate antigen and that small numbers of PBL generate high CTL responses provided non-T accessory spleen cells are added to the cultures. The system provides means to analyse the kinetics of the appearance of memory CTL precursors after primary alloimmunization in individual mice.

Animals↗
PubMed1979

Generation of cytolytic T lymphocytes in vitro. X. Induction of primary and secondary CTL responses by the mitogen sodium periodate.

Short-term (15 min) sodium periodate (NaIO4) treatment of mouse spleen cells previously primed in vivo or in vitro against alloantigens induced the formation of secondary (2 degree) cytolytic T lymphocytes (CTL) specific for the priming antigens. CTL formation was readily demonstrable within 24 hr after treatment. This early CTL response occurred equally well in the presence or absence of cytosine arabinoside (Ara C), indicating that NaIO4 could induce CTL independently of DNA synthesis. Forty-eight hours after periodate treatment, the lytic activity was similar to that observed in parallel cultures stimulated with irradiated allogeneic spleen cells, although the peak activity was reached earlier (day 4) and was somewhat lower than that induced by alloantigen. The addition of irradiated NaIO4-treated unprimed syngeneic spleen cells to cultures of untreated alloimmune spleen cells also led to CTL formation, which suggests an indirect mechanism of activation. In contrast to alloimmune spleen cells, normal spleen cells treated with NaIO4 developed only very low levels of cytotoxicity after 4 days of incubation. However, in the presence of PHA, such cells were capable of lysing syngeneic and allogeneic target cells.

Animals↗