Biomedical subjects

R Burger

Publications and source records attributed to R Burger.

At least 19 recordsLinked to original sources

PubMed1992

Macrophage-bound C3 fragments as adhesion molecules modulate presentation of exogenous antigens.

The involvement of complement in the response to T cell dependent antigens is generally accepted, however the mechanism has not been clarified. We compared the T cell response in vitro, using antigen-pulsed macrophages from normal and genetically C3-deficient guinea pigs, and show, that C3-fragments fixed covalently to the surface of the antigen-presenting cells are involved in the triggering of responder T cells. Binding of guinea pig C3-specific mAb to oil-elicited, OVA- and PPD-pulsed macrophages of C3D guinea pigs is reduced compared to normal cells, while the expression of Ia antigens is the same. C3-like peptides can be immunoprecipitated only from the lysate of oil-elicited normal cells. These C3-fragments are fixed to the cell-membrane via ester-bonds, since they are released upon treatment with hydroxylamine. In comparison with normal cells, the antigen-presenting capacity of macrophages derived from C3D animals is strongly impaired in cultures containing 10% normal guinea pig serum. A further impairment is observed in cultures with 10% C3D guinea pig serum. Two of the tested C3-specific mAb inhibited antigen-induced T cell proliferation in a dose-dependent manner. Our data point to the importance of C3, as a bivalent molecule, having the capacity to facilitate the cooperation between the antigen-presenting cell and the responder T lymphocytes.

Adjuvants, Immunologic↗

PubMed1992

Analysis of mature guinea pig T cells with a monoclonal antibody directed against a framework determinant of the T-cell receptor for antigen.

Rats were immunized with guinea pig T lymphocytes and the spleen cells were fused with cells of a mouse myeloma line. The resulting hybrids were screened for the production of antibodies selectively reacting with guinea pig T cells. The monoclonal antibody (MoAb) H159 was analysed in detail because it bound to T lymphocytes, but not to B lymphocytes or macrophages. Cellular ELISA, cytofluorometry and immunohistology revealed that the antigen detected by H159 is selectively expressed on the majority of peripheral mature T lymphocytes (about 95%). In contrast, it stained only a minor population of thymocytes in FACS analysis. H159 precipitated from NP40 lysate of T cells a protein with a molecular weight of about 90 kDa when separated under non-reducing conditions in SDS-PAGE. Under reducing conditions bands with molecular weights of about 50 kDa were found. After binding to anti-rat Ig coated beads, the MoAb H159 had a mitogenic effect for guinea pig T lymphocytes whereas soluble MoAb H159 in the presence or absence of macrophages was not mitogenic. The cellular expression and molecular characteristics of the H159 antigen together with the mitogenic activity of the antibody for T cells indicate that the MoAb H159 recognizes the guinea pig T-cell receptor for antigen via a constant region determinant.

Animals↗

PubMed1992

Utilization of pulse oximetry for the study of the inhibitory effects of antiviral agents on influenza virus in mice.

Pulmonary disease in mice induced by influenza virus was monitored by measurement of oxygen saturation (SaO2) in blood with a pulse oximeter. The SaO2 declined in inverse proportion to the viral inoculum. The known antiviral agent ribavirin inhibited the SaO2 decline, prevented death, lowered lung consolidation, and reduced the level of recoverable virus. Pulse oximetry is an effective means of monitoring murine influenzal disease and can be used in the study of potential antiviral drugs.

Animals↗

PubMed1992

[Diagnosis of brain death].

From the medical, the juridical as well as the theological point of view brain death represents the death of an individual. According to the German Chamber of Physicians, acute brain damage with coma, absence of all brainstem reflexes and apnoe allows the diagnosis of cerebral death, if repetition of the physical examination after distinct time intervals documents the irreversibility of this state. Additional investigations such as EEG, evoked potentials (BAEP), transcranial doppler sonography, brain scintigraphy or cerebral angiography allow to shorten this period if electrocortical silence, absence of waves 3-5 of BAEP or the cessation of cerebral perfusion has been proven. Strict observation of these criteria is mandatory for the diagnosis of brain death.

Brain Death↗

PubMed1992

Strain- and age-associated differences in lymphocyte phenotypes and immune responsiveness in C4-deficient and Albany strains of guinea-pigs.

Spleen lymphocytes from C4-deficient (C4D) and Albany strains of guinea-pigs, 1-7 days, 3-6 and 12-16 months old, genetically related to inbred strains 13 and 2 respectively, were analysed in terms of their expression of cell surface markers, allogenic and T- and B-cell mitogenic responses, and interleukin-1 (IL-1) and IL-2 production. There were strain- and age-associated differences in phenotypic expression and immune responsiveness levels. In both strains a significant shift in immunocompetence apparently occurs postnatally before 3-6 months of age, with no further significant changes noticed in animals 12-16 months old. Phenotypic changes in cell surface markers did not always correlate with functional capability of lymphoid cells. H159+ (pan T) and H155+ (CD4) lymphocyte number and levels of T-cell responsiveness (mitogenic and allogenic responses, and IL-2 production) were higher in C4D neonates compared with age-matched Albany guinea-pigs or with young animals of the same strain. On the other hand, 31D2+ (B) lymphocytes in a significantly higher proportion in Albany neonates compared with similarly aged C4D, did not correlate at this age or at any other time with their proliferative response to lipopolysaccharide (LPS) or dextran sulphate (DS), two B-cell-specific mitogens.

Aging↗

PubMed1991

T cell proliferation induced by monoclonal antibodies to a phosphatidylinositol-linked differentiation antigen of guinea pig lymphocytes.

Monoclonal antibodies (mAb) to differentiation antigens frequently influence the in vitro function of antigen-bearing cells. We characterized a 32-36-kDa membrane protein expressed on guinea pig lymphocytes and Langerhans cells. A series of independently derived mAb to this protein, now called guinea pig T cell activation antigen (gpTAA), induced strong proliferation of T cells in vitro. Cross-linking of the mAb by a secondary antibody (rabbit anti-mouse Ig) and costimulation with phorbol 12-myristate 13-acetate were required for activation. Treatment of the cells with phosphatidylinositol-specific phospholipase C greatly reduced the amount of antigen expressed on the cell surface as measured by flow cytometry analysis. This finding indicates that the antigen is anchored to the cell membrane via phosphatidylinositol linkage as shown similarly for other membrane proteins with T cell activating properties, e.g. Thy-1 and Ly-6. The guinea pig protein differs, however, in its molecular weight and tissue distribution from similar proteins identified in the mouse or in the rat system. Unlike Thy-1, gpTAA is also expressed on B Lymphocytes and Langerhans cells. Considering the previously described involvement in cellular adhesion, and the functional characteristics reported here, gpTAA might represent a new species of differentiation antigen with T cell-activating capacity.

Animals↗

PubMed1991

Monoclonal antibodies EBU-141 (CDw75) and EBU-65 allow reliable distinction between mature and pre-B-cell tumors in suspension and on tissue sections.

Two new monoclonal antibodies, EBU-65 and EBU-141, were raised by immunization with plasma cell line U-266. Both antibodies strongly react with B lymphocytes in immunofluorescent staining as well as on paraffin-embedded sections. More than 200 leukemias and lymphomas were tested, and for both antibodies reactivity was found only with "mature" B-cell tumors but not with precursor B-cell leukemias. None of the non-B-lineage hematolymphatic tumors tested was stained by EBU-141 or EBU-65. A subpopulation of T lymphocytes particularly present in nonmalignant pleural effusions was detected by EBU-65 additionally. Although EBU-141 was clustered as CDw75 and EBU-65 as "unique," a close relationship of the staining pattern was found and both antibodies react with a sialyltransferase. In particular, CDw75 antibody EBU-141 was demonstrated to be very useful for immunophenotyping of B-cell neoplasias, while EBU-65 reacted with most multiple myelomas and a subgroup of "activated"-appearing T cells.

Animals↗

PubMed1991

Tumour rejection after adoptive transfer of line-10-immune spleen cells is mediated by two T cell subpopulations.

The growth of line-10 tumours in naive guinea pigs is prevented by adoptive transfer of spleen cells that are hyperimmune to this hepatocellular carcinoma. To study the T cell subpopulations responsible for the adoptive transfer of immunity, various cell populations were removed from immune spleen cells using monoclonal antibodies (mAbs) and magnetic microspheres. Spleen cell subpopulations were identified by mAb after flow cytometry and rosette formation with the magnetic microspheres. mAb CT5 was confirmed to be a pan T cell marker, while the CT6 (anti-T-suppressor/cytotoxic) and CT7 (anti-T-cell) markers were present on two different T cell subpopulations. So our results show that CT7 mAb cannot be used as a pan T cell marker as was published previously. Moreover, the mAb H155 (anti-T-helper/inducer) reacted with the same T cell subpopulation recognized by CT7. So we designated this H155/CT7-positive subpopulation as T helper/inducer cells. Removal of the CT6-, CT7-, or the H155-positive T cells from the immune spleen cells resulted in loss of the in vitro proliferative response to line-10 tumour protein and tuberculin purified protein derivative (PPD). The H155/CT7 (anti-T-helper/inducer)-positive spleen cells did not express MHC class II antigens as determined by mAb 25E3. In most experiments, elimination of MHC-class-II-positive cells did not change the in vitro proliferative response to line-10 protein, whereas the response to tuberculin PPD was completely abrogated. Immune spleen cells after depletion of CT6-, CT7- or H155-positive cells, failed to transfer immunity. However, after depletion of MHC-class-II-antigen-positive cells the line-10 immunity was still present, whereas the immune response to tuberculin PPD was lost. In conclusion, our data indicate that immunity to the line-10 tumour is the result of a cooperation between at least two different T cell subpopulations, the T helper/inducer (CT7/H155) cells and the T suppressor/cytotoxic cells (CT6). If this is a common feature, then the therapeutic approach of in vitro expanded TIL cells should take into consideration the requirement of two T cell subsets.

Animals↗

PubMed1991

Low maternal CD4 count at inception of gestational cytomegalovirus (CMV) infection and impaired humoral response: effect on congenital CMV infection in the guinea pig.

In humans, the rate and clinical expression of disease in congenitally cytomegalovirus (CMV)-infected infants is modified by maternal immunity to CMV. We used the guinea pig model of congenital CMV infection to compare maternal CD4+ T-cell numbers in nonpregnant animals to those in pregnant dams just before and 7-14 days after inoculation with guinea pig CMV (gpCMV) very early, early, or late in gestation. We also examined ELISA antibody responses to gpCMV in the inoculated nonpregnant and pregnant animals. When compared to nonpregnant uninfected animals, CD4 counts were lower in very early and in late uninfected gestation. CD4 counts also dropped further in the postinoculation period. Compared to nonpregnant gpCMV-inoculated animals, initial antibody responses to gpCMV were also decreased in gpCMV-infected pregnant dams. The group of dams inoculated very early in pregnancy experienced delays in seroconversion to gpCMV, persisting low titers throughout gestation, in utero fetal resorptions, and CNS-infected pups. The group of dams inoculated late in gestation had the lowest geometric mean titers at delivery (almost 50% with no detectable antibody) and a high rate of vertical gpCMV transmission and postnatal pup death. Significantly lower rates of both congenital infection and postnatal pup deaths were observed in litters of late gestation-infected dams that had gpCMV antibody at delivery. Thus, decreased circulating maternal CD4+ T cells very early and late in gestation were further decreased after gpCMV inoculation and were associated with delayed and depressed maternal antibody responses, all of which were associated with poor outcome after primary maternal gpCMV infection, the expression of which varied by time in pregnancy when gpCMV was acquired.

Animals↗

PubMed1991

Production of antibodies to the constant region of the mouse T-cell-receptor beta-chain.

To generate antibodies to the constant region of the mouse T-cell-receptor beta chain, the corresponding cDNA clone 86T5 was subcloned into the bacterial expression vector pEX2. The induced hybrid protein consisting of a 30 kDa T-cell-receptor segment and a beta-galactosidase carrier moiety was used for immunization. In Western blots using lysates of a T-cell-receptor-positive T-cell hybrid, the antisera obtained reacted with a 42 kDa protein under reducing and a 85 kDa protein under nonreducing conditions. The antisera did not react in binding assays with intact T lymphocytes, i.e. membrane-associated T-cell-receptor protein.

Animals↗

PubMed1991

Major histocompatibility complex restriction of T-cell responses to varicella-zoster virus in guinea pigs.

Varicella-zoster virus (VZV), adapted to grow in guinea pig fibroblasts, was injected subcutaneously into Hartley, strain 2, and strain 13 guinea pigs. Serum immunoglobulin G antibodies were detected 2 weeks later, and T-cell proliferative responses by blood lymphocytes were found 3 weeks after injection. The proliferating cells bound the 155 antibody, which defines a CD4-like subset of guinea pig T lymphocytes. VZV-infected fibroblasts of human, Hartley, and strain 13 origin elicited equivalent amounts of proliferation, which was quantitatively greater than that obtained with an extracted VZV antigen. Uninfected (control) human or guinea pig fibroblasts did not elicit T-cell proliferation. The proliferative response to VZV required the presence of autologous (strain 2 or 13) antigen-presenting cells and was blocked by the addition of an anti-class II major histocompatibility complex antibody. Effector cells obtained from in vitro cultures mediated class II-restricted cytotoxicity to L2C cells incubated with VZV. Class I-restricted responses were obtained only by cross-priming strain 2 animals with strain 13 peritoneal exudate cells which had been preincubated with VZV. The data indicate that guinea pigs resemble humans in that class II-restricted T cells with specificity for VZV are more readily cultured from blood than are class I-restricted cells.

Animals↗

PubMed1991

Pulmonary hypertension after postlavage lung injury in rabbits: possible role of polymorphonuclear leukocytes.

Previous studies showed that repeated lung lavage leads to a severe lung injury with very poor gas exchange, a substantial protein leak into the alveoli with hyaline membrane formation, pulmonary hypertension, and migration of granulocytes (PMN) into the alveolar spaces. Depletion of PMN leads to a better gas exchange and a markedly decreased protein leak with only scanty hyaline membranes. In this study we show that there is sustained pulmonary hypertension after the lung lavage, but in PMN-depleted rabbits there is no postlavage increase in pulmonary arterial pressure. Changing the shunt fraction by manipulating mean airway pressure still leads to a hypoxic vasoconstriction with increase of pulmonary arterial pressure. Thus, after lung lavage, pulmonary reactivity to hypoxia is still preserved. Comparisons between high-frequency ventilation and conventional mechanical ventilation at the same mean airway pressures showed that equal mean airway pressure in these two very different modes of ventilation do not translate into the same mean functional lung volumes.

Animals↗

PubMed1991

Identification and functional characterization of guinea-pig CD4: antibody binding transduces a negative signal on T-cell activation.

The guinea-pig (gp) CD4 protein was identified using the rat monoclonal antibody (mAb) H155 derived from an interspecies hybrid. The hybrid was obtained after immunization of rats with purified guinea-pig T lymphocytes and fusion to a mouse myeloma line. The mAb H155 reacted with a subpopulation (60-70%) of nylon-wool-purified guinea-pig T cells. The majority of thymocytes also expressed the H155 antigen. Immunohistological staining showed that predominantly the cortical thymocytes were H155-positive, whereas a part of the medullary cells did not express the antigen. After cell-surface radioiodination of T cell lines, the mAb H155 immunoprecipitated a molecule of about 55,000 MW both under reducing and non-reducing conditions. The antigen recognized by mAb H155 on guinea-pig T cells resembles the human or mouse CD4 antigen. Depletion experiments in combination with functional studies further supported this assumption. In proliferation assays mAb H155 inhibited T-cell responses in vitro. Both the antigen- and alloantigen-induced T-cell activation were impaired in the continuous presence of mAb H155. In addition, mAb H155 inhibited both the mitogen-induced T-cell activation and T-cell proliferation induced by mitogenic mAb and phorbol myristate acetate (PMA). Binding of the mAb H155 to the CD4 molecule might therefore transduce a negative signal on T-cell activation.

Animals↗

PubMed1990

[A case from practice (172). Hereditary fructose intolerance].

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Child↗

PubMed1990

C3 deficiencies.

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Animals↗

PubMed1990

Reflection of changes in membrane constituents in various regions of Alzheimer brains to differential scanning thermograms.

To test whether changes in basic biochemical membrane constituents were reflected in membrane fluidity measurements, protein, total lipids, triglycerides, lecithin, cholesterol and alkaline phosphatase were determined in frontal cortex, hippocampus, putamen and nucleus basalis Meynert (NbM) of DAT brains and controls and compared to differential scanning thermograms. Biochemical changes were most pronounced in the hippocampus, while thermostability was altered in the NbM and the frontal cortex. The results indicate that changes in protein content, but not in lipid composition were reflected in alterations of thermostability of the brain regions examined.

Aged↗

PubMed1990

Brainstem lesion revealed by MRI in a case of Leigh's disease with respiratory failure.

This 6-year-old girl was admitted with insufficient involuntary breathing and generalized hypotonia. T2-weighted MR images showed bilateral symmetrical tubular hyperintense lesions in the medio-caudal part of the medulla oblongata that correlated well with demyelination and gliosis in the regions of the reticular formation and the nucleus solitarius found at autopsy. The typical lesions of Leigh's disease in the basal ganglia were not present, which made the diagnosis uncertain prior to the histopathological findings. MRI was very helpful in deciding on further management of the patient.

Brain Diseases, Metabolic↗

PubMed1990

Tumor infiltrating leukocytes (tils) during progressive tumor growth and BCG-mediated tumor regression.

Tumor regression was induced by intralesional injection with BCG, 7 days after inoculation of line 10 hepatocellular carcinoma cells into strain 2 guinea pigs. Tumor-infiltrating leukocytes (TILS) were characterized immunohistochemically with 11 monoclonal antibodies (MoAbs) during the induction phase of line 10-immunity, and during immune-mediated regression of the tumor, at days 12 and 28 after tumor cell inoculation, respectively. At day 5 after BCG-injection (day 12 after tumor cell inoculation), there were no major differences between the TIL subpopulations of the BCG-treated and untreated tumors. The TILS were mainly T-cells, as identified by MoAbs against Pan T-cells (CT5), T-cytotoxic/suppressor cells (CT6) and T-helper/inducer cells (H155). A limited number of macrophages was also present. However, at day 21 after BCG-treatment (28 days after tumor cell inoculation), the fibrous stroma was increased dramatically in most of the BCG-treated tumors, and as a result, the tumor cell islets were smaller than in control tumors. In the BCG treated tumors, the numbers of T-cells and macrophages were increased. In growing and regressing tumors, MHC class I and II antigens were strongly expressed in TILS and in the tumor stroma. Line 10 tumor cells prior to inoculation expressed no MHC class I or II antigens. In the centers of the tumor islets at days 12 and 28, expression of these antigens was not found. However, MHC class I and II antigens were expressed on tumor cells at sites where they lay close to the fibrous stroma or TILS. This observation was made in progressively growing tumors and was most apparent in BCG-treated tumors.

Animals↗