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H Hengartner

Publications and source records attributed to H Hengartner.

At least 307 records · Page 17Linked to original sources
PubMed1983

Characterization of cloned cytotoxic lymphocytes with NK-like activity.

Cloned H-2b-restricted male antigen-specific cytotoxic T cells were kept in culture in the presence of IL 2 for over 2 yr. During this time, they lost their antigenic specificity and now exhibit high NK-like activity. Three separate clones HY 1, HY 2, and HY 3 and their subclones, when tested on a panel of NK-sensitive and NK-insensitive target cells, showed typical lysis patterns of NK cells. Three cytotoxicity-loss mutants were obtained by subcloning. At least one of these cytotoxicity-loss mutants still exhibited binding to NK-sensitive target cells. The various HY clones were compared with cloned alloreactive cytotoxic T cells of B10 anti-B10.D2 specificity with respect to surface markers, target specificity, kinetics of lysis, morphology, and influence of monoclonal antibodies and chemicals on cytotoxicity. Only one major difference between cloned NK-like and alloreactive T cells was detected: monoclonal anti-Lyt-2 antibodies inhibited cytotoxic activity of alloreactive T cells but not of NK-like cells, although both expressed Lyt-2 on their surface. Morphologically, HY cells were characterized by numerous lysosomal granules in their cytoplasm. Clones with NK-like activity differed from cytotoxicity-loss mutants by both ultrastructural appearance and enzyme histochemistry of lysosomes. Interaction of NK-like cells with YAC-1 cells induced membrane lesions of variable size in target cells. Effects of chemicals influencing lysosomal pathways such as monensin, NH4Cl, and chloroquine on cytotoxicity were investigated. Monensin as well as NH4Cl inhibited cytotoxicity of NK as well as alloreactive clones, whereas chloroquine did not. Spleen cells from acutely virus-infected mice with high NK reactivity showed the same behavior except for chloroquine, which was slightly inhibitory. The addition of monensin to the cells resulted in morphologic changes in the lysosomal granules. These data strongly suggest that NK-like killing is triggered by unknown substance(s) released from lysosomes of effector cells. Cloning of antigen-specific cytotoxic T cells under conditions of limiting dilution and continuous growing in medium containing Con A supernatant but not the relevant antigen often leads to loss of specificity and appearance of NK-like activity. The results presented are representative of a great amount of work in this and probably many other laboratories attempting to clone cytotoxic effector T cells.

Animals↗
PubMed1983

Specificity of in vitro cytotoxic T cell clones directed against vesicular stomatitis virus.

Cytotoxic T lymphocytes (CTL) generated in mice against a particular serotype of vesicular stomatitis virus (VSV) were previously shown to cross-reactively lyse syngeneic target cells infected with serologically distinct types of VSV. To analyze the antigenic basis of this T cell cross-reactivity, we generated CTL against VSV-Indiana (VSV-Ind) and established them by limiting dilution as cloned in vitro cell lines. The cells continuously proliferate in medium containing concanavalin A-induced T cell growth factors. All of the cells are Thy-1.2+ and Lyt-2.2+. Lysis by these cells is H-2Dd-restricted, no natural killer cell activity is detectable, and all the clones cross-reactively lyse target cells infected with either VSV-Ind or VSV-New Jersey (VSV-NJ). In addition, no specific blocking of primary, secondary, or cloned anti-VSV CTL was achieved with the use of several monoclonal antibodies specific for the glycoprotein of VSV and capable of neutralizing either VSV-Ind or VSV-NJ. These results suggest that VSV serotype-specific neutralizing antibodies may recognize immunodominant determinants of VSV glycoprotein that are distinct from those recognized by the majority of VSV-specific CTL.

Animals↗
PubMed1982

NK-patterned binding expressed by non-NK mouse leukocytes.

Previous studies demonstrated that NK-cell-enriched spleen cells bind to sensitive but not to resistant mouse lymphoma targets, measured by a single-cell target binding assay. In the present report we further analyzed this "NK-patterned" binding using effector cells with high, low or no NK activity. In agreement with previous results, nylon-wool-passed spleen cells as well as a cloned cytotoxic cell line with NK activity bound tumor targets largely according to their NK sensitivity; NK-sensitive tumors had a higher frequency of binders than the more resistant ones. The correlation coefficient relating the percentage target binding cells (TBC) for each tumor with the ability of the same tumor to inhibit lysis in cold target competition assays was consistently higher than that relating percentage TBC with direct NK lysis. A non-lytic variant of the cloned cytotoxic cell line had a binding pattern identical to that of the lytic line, demonstrating that "NK-patterned" binding occurred in the absence of lysis. Thymocytes, which are totally devoid of NK activity, also bound preferentially NK-sensitive targets, and their binding was decreased after trypsin treatment or in the presence of EDTA. Peritoneal macrophages also showed "NK-patterned" binding, thus demonstrating that this was not restricted to cells in the T-cell lineage. Variants from a mouse lymphoma selected for decreased NK sensitivity bound a lower frequency of NK-active (nylon-wool-passed spleen cells) and inactive cells (thymocytes, peritoneal macrophages). This study therefore showed that the membrane property conferring NK-binding selectivity exists on several types of non-NK leukocytes.

Animals↗
PubMed1982

Interleukin 1 activity in the synovial fluid of patients with rheumatoid arthritis.

The synovial fluids (SF) of patients with rheumatoid arthritis (RA) were investigated for their effects on thymocytes of C3H/HeJ mice. Of the 20 SF tested, 17 (85%) showed an augmentation of the phytohaemagglutinin (PHA) induced thymocyte stimulation. Out of 16 SF of patients with osteoarthrosis, such an activity was detected in only one (6.25%). Further characterisation of the amplification factor revealed that (1) the SF of RA patients augmented both the PHA and the Concanavalin A response of the thymocytes (2) in the absence of mitogens, SF-treated thymocytes showed an increased uptake of 3H-thymidine, (3) the SF did not propagate the growth of an interleukin 2 dependent ovalbumin specific T cell clone, but (4) the SF were found to be required for optimal interleukin 2 release by spleen cells stimulated with suboptimal doses of lectin. Based on these biological effects the factor in the SF of RA patients is suggested to represent an interleukin 1 (IL-1). IL-1 produced in cultures by activated macrophages has been shown to stimulate T and B cell functions and to induce the production of collagenase and prostaglandins by cultured synovial cells. Both properties of IL-1 could be relevant in the pathogenesis of RA.

Animals↗
PubMed1981

Somatic cell hybrids from frog lymphocytes and mouse myeloma cells.

Stable somatic cell hybrids were obtained by fusing Xenopus lymphocytes with mouse myeloma cells. These hybrids contained one to four Xenopus chromosomes and expressed Xenopus gene products, one of which was a lymphocyte membrane protein of 85,000 daltons precipitated by a monoclonal antibody.

Animals↗
PubMed1980

An immunoglobulin heavy-chain gene is altered in two T-cell clones.

Thymus-derived lymphocytes (T cells) show a high degree of discrimination in their responses to various antigens, very similar to the specificity repertoire of antibody-producing B cells. The nature of the T-cell receptor which mediates antigen recognition is obscure, but the ability to discriminate between antigenic specificities implies a range of receptor specificities. Many serological and genetic data suggest that T-cell receptors use the immunoglobulin heavy (H)-chain variable (V) region genes but do not carry the antigenic determinants of the immunoglobulin H-chain constant (C) regions; they also do not seem to carry conventional light (L)-chain V- or C-region determinants. In B cells and derivatives the expression of immunoglobulin genes is manifested, at the DNA level, by an alteration of the restriction enzyme patterns of both the H and L immunoglobulin genes. Specifically, V-gene integration involves joining of a V gene with a J segment (in the case of the H chain probably through an intermediate D segment) so that sites for restriction enzymes will undergo changes in cells in which V-J joining has occurred. Here, we describe Southern filter hybridization experiments using C mu and C kappa probes on the DNA of individual T-cell clones from mice, and present evidence for alteration of sequences adjacent to the C mu gene in the cells.

Animals↗
PubMed1980

Clones of alloreactive T cells. I. A. unique homozygous MLR-stimulating determinant present on B6 stimulators.

We have developed a method which allows us to clone and reclone primed responder T cells derived from serially restimulated murine mixed lymphocyte cultures. We have derived clones from two such mixed lymphocyte cultures, A anti-B6 [A(B6)] and A anti-(B6XA)F1 [A(B6A)]. In the A (B6) system, we have isolated clones which can ve stimulated by B6 but not by (B6XA)F1 cells. This implies the presence of a unique parental H-2b MLR determinant which is absent on semi-allogeneic (B6XA)F1 cells. In the A(B6A) system, we have isolated clones which can be stimulated by (B6XA)F1 cells but not by B6 cells. This confirms our previous observation on the presence of unique hybrid MLR stimulating determinants on (B6XA)F1 cells. Many of the "clones" derived primarily from soft agar seem to be contaminated and contain several different sets of primed responder cells with different reactivity patterns . Experiments in which we subclone cells exhibiting selected reactivity patterns from such contaminated primary clones suggested that a T-cell growth factor or accessory cell is required for proliferation in soft agar following all antigen recognition by primed responder cells.

Animals↗
PubMed1980

Characterization of cloned murine cytolytic T cell lines.

Murine cytolytic T lymphocytes can be kept in continuous culture apparently indefinitely by repeated passage in a concanavalin A-induced growth promoting medium. Some of these long-term cell lines maintain their cytolytic activity. Starting from three such populations, several cloned cytolytic T cell lines were derived and subsequently subcloned one or more times. Considerable variation in the levels of cytolytic activity was observed between different subclones; some initially active subclones lost activity with prolonged culture. In addition, one of the clones appeared to progressively lose the relative specificity demonstrated during the earlier passages of the parent cell line.

Animals↗
PubMed1979

Fine specificity of a continuously growing killer cell clone specific for H-Y antigen.

H-Y-specific cytotoxic T cells were first cloned in soft agar and grown over a period of 8 months in media conditioned with supernatants from mouse and rat spleen cells stimulated with concanavalin A. The specificity of cloned cells and their cytolytic potential remained essentially unchanged over the entire culture period. In addition to lysing male target cells expressing H-2Db antigens, the cytolytic cells lysed also male as well as female cells expressing H-2Dd alloantigens. Seventeen out of eighteen subclones derived from the original clone revealed the same activity. The cells divide about every 17--20 h can be obtained in large quantities.

Animals↗
PubMed1979

Crossreactive mixed lymphocyte reaction determinants recognized by cloned alloreactive T cells.

We have isolated clones of alloreactive T cells by soft agar cloning of primed responder cells contained in serially restimulated, mixed lymphocyte cultures. These clones recognize unique mixed lymphocyte reaction (MLR) stimulating determinants present on (C57B/6 X A/J)F1 (B6A) spleen cells. By assaying the reactivity patterns of these clones on a panel of stimulator cells, we have identified at least three separate "specificities" of alloreactive T cell clones. Several clones exhibiting one of these three reactivity patterns have been isolated on many occasions from different experiments. Using such clones of alloreactive T cells, we have identified and are attempting to define crossreactive MLR stimulating determinants exhibited by a panel of stimulator cells. Recognition by certain clones of a shared MLR determinant(s) on B6A and DBA/2 and of the lack of this determinant(s) on B6 stimulator cells questions current concepts concerning the nature of MLR stimulating determinants and T cell recognition of alloantigens.

Animals↗
PubMed1979

Induction of plaque-forming cells in human blood lymphocytes cultured in the presence of antigen and Epstein-Barr virus: a study with normal donors and infectious mononucleosis patients.

Normal human peripheral blood lymphocytes, stimulated in vitro with SRBC in the presence of Epstein-Barr virus (EBV), gave rise to plaque-forming cells (PFC) specific for the antigen. PFC levels were very low before day 4 and increased thereafter, reaching a maximum around day 8. However, the kinetics of the response varied considerably from donor to donor and from experiment to experiment. In some instances a second peak of PFC was obtained beyond day 10. Large differences in the magnitude of the response were observed among different normal donors, the overall responsiveness range covering four orders of magnitude. Peripheral blood lymphocytes from infectious mononucleosis patients in the acute stage of the disease, when a high titre of heterophil and anti-EBV antibodies were present, did not give rise to PFC. A return to normal responses was observed during recovery from the disease.

Adult↗
PubMed1978

Immunoglobulin production by lymphocyte hybridomas.

We have investigated immunoglobulin production by cloned hybrid cells. gamma2b heavy chains, but not gamma1 or gamma21, exist in two forms, differing in molecular weight, galactose labeling and charge. Hybrid molecules containing gamma2b and gamma1 heavy chains were secreted by hybridoma cells synthesizing Ig molecules of both subclasses. However, cells synthesizing both IgM and IgG chains did not secrete mu-gamma hybrid molecules. We have surveyed many new hybridomas derived from different mouse strains: 10% of those secreting IgM produce a mu chain which is about 5000 daltons larger than normal mu. Two IgM-secreting lines were studied in detail and were found to bear mu but not delta in their membrane. Intra- and extracellular mu differ in molecular size; pentameric IgM-containing molecules of both sizes were observed in the membrane fraction.

Animals↗
PubMed1978

Assignment of genes for immunoglobulin kappa and heavy chains to chromosomes 6 and 12 in mouse.

Using somatic cell hybrids from fusions of lymphocytes of two different mouse stocks with the myeloma cell line X63-Ag8, we have assigned genes for the immunoglobulin heavy and kappa-type light chains to chromosomes 12 and 6, respectively. The two mouse stocks exhibit karyotypes consisting of nine pairs of metacentric chromosomes as a result of centric fusions of acrocentric chromosomes in different combinations. In the hybrid cells these metacentric chromosomes can be distinguished from the acrocentric chromosomes of myeloma origin, permitting correlation of Ig chain expression with mitotic loss of individual metacentric chromosomes.

Animals↗