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Biomedical subjects

H Hengartner

Publications and source records attributed to H Hengartner.

At least 289 records · Page 16Linked to original sources
PubMed1986

Generation of agammaglobulinaemic mice by prenatal and postnatal exposure to polyclonal or monoclonal anti-IgM antibodies.

Improved experimental conditions are described for the treatment of mice with anti-IgM antibody, which subsequently lead to B-cell deficiency and agammaglobulinaemia. Antibody transmitted via maternal milk alone was found to be more efficient in inducing suppression of serum immunoglobulin isotypes than prenatal transmission or postnatal intraperitoneal injections alone. However, the combined treatment by all three routes of exposure to anti-IgM resulted in total B-cell suppression associated with undetectable levels of all serum immunoglobulin isotypes. Furthermore, suppression of B-cell generation was also achieved with a rat monoclonal mu-specific antibody. The possibility of generating agammaglobulinaemic mice may be useful for investigating the influence of B cells on the generation of T-cell reactivities, and for analysing the effects of monoclonal antibodies in the absence of interfering serum immunoglobulin.

Agammaglobulinemia↗
PubMed1986

Effect of cyclosporin A on immunity to Listeria monocytogenes.

The effect of the immunosuppressive drug cyclosporin A (CS-A) on immunity to the facultative intracellular bacterium Listeria monocytogenes was investigated in unprimed and primed mice. Different treatment protocols were followed to evaluate the time dependence of CS-A-mediated immune suppression and the effect of CS-A on immunological memory to L. monocytogenes. The effect of CS-A was observed only during and after activation of T cell-mediated immunity, whereas early resistance exerted by macrophages assessed 6 and 70 min after challenge remained unaffected. CS-A suppressed efficient elimination of L. monocytogenes even when given after day 3 of a primary infection. This contrasts with findings in other models, including viral infections, where CS-A must be administered very early in an immune response to suppress it. CS-A suppressed antibacterial resistance in mice primed at various times before challenge; suppression of protection was time dependent and was virtually complete in livers, whereas CS-A-resistant memory persisted in spleens for up to 10 months.

Animals↗
PubMed1986

Effects of cyclosporin A on humoral immune response and resistance against vesicular stomatitis virus in mice.

The effect of cyclosporin A (CS-A) on the antiviral humoral response was studied by using vesicular stomatitis virus (VSV); VSV provided the opportunity to simultaneously assess both T-independent and T-dependent antibody responses. The T-independent anti-VSV immunoglobulin M (IgM) response was virtually unaffected, whereas the T-dependent primary anti-VSV IgG response was suppressed by CS-A; in contrast, the secondary IgG response was highly resistant to CS-A. Moreover, once the switch from IgM to IgG had occurred, the primary response also became refractory to suppression by CS-A. We concluded that the effect of CS-A on the primary anti-VSV antibody response was mediated via impairment of a T-dependent mechanism; in contrast, memory T cells or memory B cells or both were quite resistant to the suppressive effects of CS-A. CS-A treatment rendered mice highly susceptible to VSV infection; under CS-A treatment, mortality was 100% after infection via footpads, whereas immunocompetent mice survived. Since CS-A does not impair induction of early T-independent anti-VSV IgM neutralizing antibodies, this high mortality in CS-A treated mice illustrates the crucial role of CS-A-sensitive cells in resistance against VSV.

Animals↗
PubMed1986

Persistence of vesicular stomatitis virus in cloned interleukin-2-dependent natural killer cell lines.

We have investigated virus-lymphocyte interactions by using cloned subpopulations of interleukin-2-dependent effector lymphocytes maintained in vitro. Cloned lines of H-2-restricted hapten- or virus-specific cytotoxic T lymphocytes (CTL) and alloantigen-specific CTL were resistant to productive infection by vesicular stomatitis virus (VSV). In contrast, cloned lines of natural killer (NK) cells were readily and persistently infected by VSV, a virus which is normally highly cytolytic. VSV-infected NK cells continued to proliferate, express viral surface antigen, and produce infectious virus. Furthermore, persistently infected NK cells showed no marked alteration of normal cellular morphology and continued to lyse NK-sensitive target cells albeit at a slightly but significantly reduced level. The persistence of VSV in NK cells did not appear to be caused by the generation of temperature-sensitive viral mutants, defective interfering particles, or interferon. Consequently, studies comparing the intracellular synthesis and maturation of VSV proteins in infected NK and mouse L cells were conducted. In contrast to L cells, in which host cell protein synthesis was essentially totally inhibited by infection, the infection of NK cells caused no marked diminution in the synthesis of host cell proteins. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of immunoprecipitates of viral proteins from infected cells showed that the maturation rate and size of VSV surface G glycoprotein were comparable in L cells and NK cells. Nucleocapsid (N) protein synthesis also appeared to be unaffected in NK cells. In contrast, the viral proteins NS and M appeared to be selectively degraded in NK cell extracts. Mixing experiments suggested that a protease in NK cells was responsible for the selective breakdown of VSV NS protein. Finally, VSV-infected NK cells were resistant to lysis by virus-specific CTL, suggesting that persistently infected NK cells may harbor virus and avoid cell-mediated immune destruction in an immunocompetent host.

Animals↗
PubMed1985

Susceptibility to lymphocytic choriomeningitis virus isolates correlates directly with early and high cytotoxic T cell activity, as well as with footpad swelling reaction, and all three are regulated by H-2D.

The lymphocytic choriomeningitis virus (LCMV) isolates Docile (D) and Aggressive (A) of Pfau et al. were studied in various strains of mice. Disease susceptibility, assessed as mortality and time to death to LCMV-D or -A varied greatly amongst mouse strains, and all four possible susceptibility patterns were observed: susceptibility to both (e.g. SWR/J), resistance to both (e.g. DBA/2), susceptibility to A but resistance to D (C57BL/6), or vice versa (CBA/J). Irrespective of the virus isolate or the mouse strain tested, susceptibility correlated with both early and high cytotoxic T cell activity found in spleens or leptomeningeal infiltrates, and with early and high primary footpad swelling reaction after local infection. C57BL/6 mice infected with A or SWR/J infected with A or with D showed, in both test systems, early and high activities; in contrast, DBA/2 mice infected with either D or A, and C57BL/6 infected with D showed no or only slow and low responses in both tests. Early and high LCMV-specific cytotoxic T cell activity, and the rapidity and extent of the primary footpad reaction directly correlated with susceptibility to LCM and all were dominantly regulated by H-2D.

Animals↗
PubMed1985

5'-O-Palmitoyl- and 3',5'-O-dipalmitoyl-5-fluoro-2'-deoxyuridine--novel lipophilic analogues of 5'-fluoro-2'-deoxyuridine: synthesis, incorporation into liposomes and preliminary biological results.

5'-O-palmitoyl- and 3',5'-O-dipalmitoyl-5-fluoro-2'-deoxyuridine were prepared by the reaction of 5-fluoro-2'-deoxyuridine in dimethylacetamide with palmitic acid chloride. The incorporation of the synthesized prodrugs into liposomes composed of egg phosphatidylcholine/stearylamine/cholesterol/alpha-tocopherol at a molar ratio of 10:1:2:0.05 was nearly quantitative; homogeneous bilayer vesicles (75 nm diameter) were obtained. Preliminary tolerance studies revealed that the prodrug-liposome preparations are about 20-60 times more toxic than the parent drug. The prodrugs incorporated into liposomes were 10 to 30 times more active against murine colon 38 carcinoma compared to the free drug. In comparison to the administration of the prodrugs in peanut oil the liposomal preparations seem to exert improved effects and represent a valuable drug delivery system for parenteral applications.

Animals↗
PubMed1985

Cytotoxic T cell clone-specific monoclonal antibodies used to select clonotypic antigen-specific cytotoxic T cells.

Two rat monoclonal antibodies (mAb) have been produced which recognize a clone-specific determinant on the alloreactive cytotoxic T lymphocyte (CTL) clone 3 F9. CTL clone 3F9 of BALB/c origin is specific for H-2Db and can be grown by weekly restimulation with irradiated stimulator spleen cells expressing H-2Db in the presence of interleukin 2. Two mAb against T cell clone 3F9, 44-22-1(IgG2a) and 46-6 B5(IgM), have been proven to be clone specific: they inhibit cytotoxic activity of 3F9 only and bind specifically to 3 F9 when compared in a panel of different CTL clones, or cells from different mixed lymphocyte cultures (MLC), BALB/c thymus and spleen cells. The mAb 44-22-1 has been used to sort cells from a primary MLC BALB/c anti-H-2Db by fluorescence-activated cell sorter (FACS) to select CTL expressing 3 F9 clonotype-specific determinants. The lymphocytes reactive with 44-22-1 represent a minor subpopulation of the CTL of the primary MLC. The specific alloreactive cytotoxicity of unsorted lymphocytes of the bulk primary MLC could not be inhibited by the mAb 44-22-1 and 46-6 B5 whereas the sorted 3 F9 clonotype-positive cultures could be inhibited very effectively. All the CTL clones derived from the FACS-sorted clonotype-positive culture show all the same properties and are identical with clone 3 F9 with respect to antigen-specific cytotoxicity, inhibition of cytotoxicity by the mAb and surface markers.

Animals↗
PubMed1985

Inhibition of hapten-specific cytotoxic T cell recognition by monoclonal anti-hapten antibodies.

The T cell-mediated cytotoxic response against autologous cells modified with the sulfhydryl reagent I-AED (N-iodoacetyl-N'-(5-sulfonic-1-naphthyl) ethylene diamine) is hapten specific and H-2 restricted (Levy, R. B., Shearer, G. M., Richardson, J. C. and Henkart, P. A., J. Immunol. 1981. 127: 523). We have produced a monoclonal antibody (V-6-3, IgM) which binds to AED-modified cells and proteins. Competition experiments by free hapten indicated that the binding was AED specific. The effect of the mAb on AED-specific cytotoxic T cell recognition at the effector and induction stage has been examined. Anti-AED mAb inhibited the cell-mediated lysis of some but not all AED-specific, H-2b-restricted long-term cytotoxic T cell clones and of bulk-cultured C57BL/6 anti-AED-self effector cells. This blocking was not due to nonspecific agglutination of targets since lysis of AED-modified target cells by alloreactive effector cells was not affected by this mAb under comparable conditions. Furthermore anti-AED mAb specifically inhibited the antigen-induced proliferation of AED-specific long-term cytotoxic T cell clones and the generation of AED-specific cytotoxic effector cells in secondary cultures. This monoclonal anti-AED antibody bound to cells modified by the recently described aminoreactive reagent AED-NH2 (Takai, Y., Mizuochi, H., Fujiwava, H. and Hamaoka, T., J. Immunol. 1984. 132: 57); these same target cells were, however, not lysed by AED-SH-specific cytotoxic T cell clones.

Animals↗
PubMed1985

Suppression by cyclosporin A of murine T-cell-mediated immunity against viruses in vivo and in vitro.

The immunosuppressive effect of Cyclosporin A on T-cell-mediated antiviral immune responses was examined. When administered intraperitoneally CS-A abrogated anti-vaccinia virus, anti-lymphocytic choriomeningitis virus (LCMV), and anti-vesicular stomatitis virus (VSV) T-cell responses in a dose-dependent fashion. Usually 50-60 mg/kg were efficient in suppressing primary T-cell responses completely. In contrast, 10-20 mg/kg often enhanced T-cell responses significantly when compared with controls. Suppression was observed if CS-A treatment was started before virus injection and up to 12 hr after infection; CS-A given 24 hr after the virus still suppressed T-cell activity partially. A 50 mg/kg dose of CS-A suppressed secondary anti-vaccinia virus or anti-VSV T-cell responses in vivo by a factor of about 10. This dose suppressed the primary T-cell-dependent footpad swelling induced by local LCMV infection and prevented T-cell-mediated immunopathological death due to LCM when LCMV was injected intracerebrally. In addition, clearance of LCMV was delayed drastically by CS-A treatment. When added to cultures of in vivo-primed antiviral T cells that were restimulated in vitro, CS-A inhibited both proliferation as well as generation of virus-specific cytotoxic T cells in a dose-dependent way. The results show that in CS-A-treated mice primary and secondary antiviral T-cell responses are strongly inhibited; acute viral infections with cytopathic viruses may therefore be more dramatic. In contrast immunopathological T-cell-mediated disease caused by noncytopathic viruses such as LCMV may be prevented or attenuated.

Animals↗
PubMed1985

Cytotoxic T cell lysis of target cells fused with liposomes containing influenza virus haemagglutinin and neuraminidase.

The lytic activity of secondary cytotoxic lymphocytes against influenza A virus was tested on cells which had been fused with liposomes containing the haemagglutinin and the neuraminidase of an avian influenza A virus (fowl plague virus, FPV). Fusion was obtained solely by the activity of the haemagglutinin and neuraminidase incorporated into the liposomes, without the need for any additional fusion factor. Highly reproducible lysis of these FPV-liposome target cells by influenza A-specific cytotoxic cells was found. In contrast, target cells containing the glycoproteins HN and F of Newcastle disease virus (NDV) were not lysed. In almost all experiments effector cell populations capable of lysing target cells also lysed the natural killer cell (NK)-sensitive cell line YAC-1. However, high NK activity alone was not sufficient to lyse target cells fused with liposomes containing the viral surface glycoproteins. To our knowledge this is the first report where after artificial introduction of viral surface components into cell membranes (either by fusion or by transfection) lysis of target cells was monitored also for non-specific lysis mediated by NK-like cells. Both the H-2 restriction and the virus specificity of lysis of FPV-liposome target cells indicate that influenza virus haemagglutinin and possibly neuraminidase do function as target antigens for influenza-specific T cells.

Animals↗
PubMed1985

Suppression of B cell development and antibody responses in mice with polyclonal rabbit and monoclonal rat anti-IgM antibodies. I. Characterization of the suppressed state.

Mice treated from birth with polyclonal, crude or affinity purified rabbit or monoclonal rat anti-mouse IgM antibodies [b-7-6 and C-2-23: Eur. J. Immunol. 14: 753-757, 1984] were found to be heavily suppressed with respect to B-cell activities. Crude or affinity purified rabbit or monoclonal rat anti-mouse IgM gave comparable results as follows: serum IgM was below detectable levels; serum IgG was reduced to about 1-3% of normal levels; free anti-IgM was always detectable; IgM and/or kappa-light-chain positive cells as well as IgM-secreting cells were absent in various lymphoid organs; the B-cell mitogen lipopolysaccharide was unable to induce proliferative responses; primary antibody responses could not be induced against sheep red blood cells and phosphorylcholine; lymphoid organs were reduced in size and B-cell areas were not populated with lymphocytes; besides a 40% reduction in absolute lymphocyte numbers in the blood, we found increased platelet counts and a 10% eosinophilia in anti-IgM-treated mice.

Animals↗
PubMed1985

Natural killer cells vs cytotoxic T cells in the peripheral blood of virus-infected mice.

The cell-mediated immune response of mice against various enveloped RNA and DNA viruses expressed by immune lymphocytes from the spleen and the peripheral blood (PBL) were compared. PBL from mice of various strains infected with vaccinia virus, vesicular stomatitis virus (VSV), or lymphocytic choriomeningitis virus (LCMV) were tested on histocompatible or incompatible target cells infected with the homologous virus. PBL from immune mice showed clear H-2 restriction, but additionally, they expressed high natural killing (NK) activity on YAC-1 cells. The high NK-cytolytic activity of PBL on YAC-1 differed significantly from that expressed by splenic lymphocytes. In both lymphocyte populations lysis was detected as early as 1 day after infection; NK activity decreased in the spleen after day 4 post infection, whereas that of PBL persisted at high levels for up to 10 days after infection. Treatment of mice with anti-asialo GM1 in vivo abrogated NK activity in PBL effector cells tested in vitro. These results may explain some of the difficulties to observe MHC-restricted cytotoxic T cells in PBL from humans or primates during primary infections with virus.

Animals↗
PubMed1984

Restriction fine specificity of long-term, hapten-specific cytotoxic T cell clones: analysis with H-2Kbm-mutant mice and H-2Kb-specific monoclonal antibodies.

The cell-mediated cytotoxic response against autologous cells modified with the sulfhydryl reagent I-AED [N-iodo-acetyl-N-(5-sulfonic-1-naphthyl) ethylene diamine] has been described by Levy, R. B., Shearer, G. M., Richardson, J. C. and Henkart, P. A., [J. Immunol. 1981. 127: 523.]. We have established two H-2Db- and eight H-2Kb-restricted, AED-specific long-term cytotoxic T lymphocyte (CTL) clones of C57BL/10 origin. The growth of these clones has been dependent upon presence of both antigen and interleukin 2. Cytotoxicity and proliferation analysis of AED-specific Kb-restricted CTL clones with target and stimulator cells from Kbm-mutant mice demonstrated two categories of clones (A and B) based on different reactivity patterns against hapten-modified Kbm-mutant cells. AED-modified target cells of bm5, bm6 and bm9 origin were lysed by type A clones but not by type B clones, in contrast to AED-modified bm3, bm8 and bm11 target cells which were lysed by type B but not by type A clones. None of the clones lysed AED-modified bm1 target cells, but all of them lysed AED-modified bm4 and bm10 target cells. The restriction fine specificities for both cytolytic and proliferative activities of the analyzed clones were identical. A panel of monoclonal antibodies (mAb) directed against the Kb molecule was used to inhibit lysis of AED-modified target cells by CTL clones. mAb which recognize a cluster of allodeterminants located in the second external domain (C1 domain) of the Kb molecule [Hämmerling, G. J., Rüsch, E., Tada, N., Kimura, S. and Hämmerling, U., Proc. Natl. Acad. Sci. USA 1982. 79: 4737] only inhibited type B clones, whereas inhibition of both type of clones was observed with mAb specific for allodeterminants clustered in the N-terminal region of Kb. These findings suggest that different regions on the Kb molecule serve as self determinants for H-2-restricted cytotoxicity. We also demonstrate that allodeterminants recognized by mAb and self determinants involved in H-2 restriction need not be identical. Our data also support the notion that covalent AED modification of H-2 molecules is not necessary to generate the self plus X antigen for CTL recognition.

Animals↗
PubMed1984

Expression of IgE receptors and histamine in cloned natural killer cell lines.

Natural killer (NK) activity is mediated by large granulated lymphocytes (LGL). Recently, the relationship of NK cells to mast cells and basophils has been suggested. We therefore examined three distinct interleukin 2-dependent cloned cell lines capable of mediating NK lysis. Virtually all the cells of each line contained membrane-bound granules. Interestingly, ultrastructural studies demonstrated that the granules in each cell line were morphologically distinct and thus heterogeneous. All three cloned, granulated NK cell lines were found to variably express low numbers (less than or equal to 1.3 X 10(4)) of low affinity plasma membrane IgE receptors (Fc epsilon R). In contrast to mast cells and basophils, however, none were found to express high numbers of high affinity Fc epsilon R. In addition, none of the three NK cell lines were found to contain histaminase-sensitive histamine. Our results suggest that NK cells are not related to mast cells or basophils.

Animals↗
PubMed1984

Glycosaminoglycan profiles in cloned granulated lymphocytes with natural killer function and in cultured mast cells: their potential use as biochemical markers.

Proteoglycans from three cloned, granulated lymphocyte cell lines with natural killer (NK) function (NKB61A2, HY-3, H-1) and one mast cell line (PT-18) were labeled with [35S]sulfate. [35S]proteoglycans were extracted in 1 M NaCl with protease inhibitors to preserve their native structure and were separated from unincorporated [35S]sulfate by Sephadex G-25 chromatography. [35S]proteoglycans from all four cell lines were chromatographed over Sepharose 4B and were found to have a similar range of m.w. The [35S]glycosaminoglycans from each cell line were then separated from parent proteoglycans by treatment with 0.5 M NaOH. The [35S]glycosaminoglycans from the three lymphocyte cell lines exhibited a similar m.w. as assessed by Sepharose 4B gel filtration, whereas the [35S]glycosaminoglycans from the mast cell line chromatographed as a smaller m.w. molecule. [35S )glycosaminoglycan charge characteristics were evaluated with DEAE C1-6B ion exchange chromatography. The consistency of the elution patterns was determined by using [35S]glycosaminoglycans obtained from radiolabelings of each cell line separated by 6 mo in culture. Each NK lymphocyte cell line reproducibly produced two distinct [35S]glycosaminoglycan chains that eluted in two regions well before the commercial heparin marker. The proportions of each chain were dependent upon the specific cell line. The mast cell line produced a single [35S]glycosaminoglycan chain, which eluted overlapping the internal commercial heparin marker, consistent with its higher charge characteristics. [35S]glycosaminoglycans from all cell lines were identified as chondroitin sulfates with the use of specific polysaccharidases. The NK lymphocyte glycosaminoglycans contained chondroitin 4-sulfate disaccharides. The mast cell glycosaminoglycans contained oversulfated disaccharides and chondroitin 4-sulfate disaccharides. Thus, each granulated NK lymphocyte cell line produced chondroitin sulfate glycosaminoglycans that were characteristic of that cell line and of different composition and less charge than those produced by cultured mast cells. These findings demonstrate that glycosaminoglycan profiles are useful biochemical markers in the characterization of diverse granulated cell lines including NK lymphocytes and mast cells.

Animals↗
PubMed1984

Glioblastoma cells release interleukin 1 and factors inhibiting interleukin 2-mediated effects.

Studies were designed to investigate whether the cellular immunodeficiency state observed in human glioblastoma patients could be due to inhibitory factors released by the tumor cells. Cultured human glioblastoma cells were found to secrete an interleukin 1-like factor (m.w. 22,000) and a factor (m.w. 97,000) that inhibits interleukin 2 (IL 2)-dependent T cell mechanisms. This is demonstrated by its inhibitory effect on the IL 2-induced proliferation of T cell clones and on the induction of alloreactive cytotoxic T cells in mixed lymphocyte cultures. Additionally the glioblastoma cell-derived 97,000-m.w. factor inhibited growth of neuroblasts but not of fibroblasts and thus shares the characteristics of the neuroblast growth inhibition factor (NGIF) previously detected in the supernatant of fetal rat glia cell cultures. If released by glioblastoma cells in vivo, the factor may contribute to impaired immunosurveillance and to the cellular immunodeficiency state detected in the patients.

Animals↗