PubMed Health⌕ Search

Biomedical subjects

W Müller-Ruchholtz

Publications and source records attributed to W Müller-Ruchholtz.

At least 145 records · Page 8Linked to original sources
PubMed1986

Graft-versus-host reaction in small bowel transplantation and possibilities for its circumvention.

To describe GVHR in small bowel transplantation and its underlying mechanisms and to find methods for circumventing that response, accessory small bowel transplantation was carried out in the rat model. Animals not treated with cyclosporine, irradiation, or removal of the mesenteric lymph nodes of the graft died within 22 days postoperatively due to graft versus host disease. Mesenteric lymph nodes of the graft and recipient spleen and peripheral lymph nodes showed strong immunologic stimulation histologically and high antihost T-cell-mediated cytotoxic antihost reactivity. Seventy-one percent of the animals that had received 15 mg of cyclosporine per kilogram body weight orally survived 150 days after transplantation. After donor irradiation with 50 rads, 77 percent of the recipients survived 120 days. After microsurgical removal of the mesenteric lymph nodes of the graft, 89 percent survived 120 days. We conclude that GVHR plays an important role in small bowel transplantation and that the experimental regimens of donor, graft, and recipient treatment described herein have proved their efficacy for circumventing GVHR.

Animals↗
PubMed1986

Immune reactivity after high-dose irradiation.

Immune reactivity after total-body irradiation was investigated in rats using skin graft rejection as the indicator system. After sublethal irradiation with 10.5 Gy (approximately 50% lethality/6 weeks) the rejection of major histocompatibility complex allogeneic skin grafts was delayed significantly compared with nonirradiated control animals (28 versus 6.5 days). In contrast, skin grafts were rejected after 7.5 days in sublethally irradiated animals and 7 days in lethally irradiated animals if additional skin donor type alloantigens--namely, irradiated bone marrow cells--were given i.v. either simultaneously or with a delay of not more than 24 hr after the above conditioning regimen. These reactions were alloantigen-specific. They were observed in six different strain combinations with varying donors and recipients. Starting on day 2 after irradiation, i.v. injection of bone marrow gradually lost its effectivity and skin grafts were no longer rejected with uniform rapidity; skin donor marrow given on days 4 or 8 did not accelerate skin graft rejection at all. These data show that for approximately 1-2 days after high-dose total-body irradiation rats are still capable of starting a vigorous immune reaction against i.v.-injected alloantigens. The phenomenon of impaired rejection of skin grafted immediately after high-dose irradiation appears to result from the poor accessibility of skin graft alloantigens during the early postirradiation phase when vascularization of the grafted skin is insufficient.

Animals↗
PubMed1986

Functional characterization of prethymic T cells committed to alloreactivity.

The results of previous experiments on MHC fully allogenic bone marrow transplantation (BMT) in nonthymectomizd recipients indicated that anti-MHC alloreactivity starts to become irreversibly committed at the prethymic level. This is a matter of some controversy. Since it is possible that conflicting results depend on the methods chosen, we reexamined our previous results by applying two new approaches. Adult thymectomized (ATX) Balb/c mice received a syngeneic fetal thymus either 3 weeks before or 3 weeks after lethal irradiation and reconstitution with C57BL/6 BM incubated in antiserum. Since monoclonal antibodies such as anti-Thy 1 are of limited value for investigations of the above type (Thy 1 antigen crosses the prethymic/thymic border), we used two highly selective, excessively cytotoxic xenoantisera for incubation of the donor BM--either a specific anti-T cell serum (SAT) that eliminated only mature T cells, or a specific antilymphocyte serum (SAL) that reacted additionally with a subset of prethymic T cells (PTC). In both experimental approaches the results were similar: Recipients of SAT-BM developed antihost reactivity, in contrast to recipients of SAL-BM. SAT-BM recipients became immunodeficient, whereas SAL-BM chimeras were immunocompetent. Late mortality was observed only following SAT treatment. Preliminary morphological findings in the lymphoid tissue of BM recipients agree fully with the functional observations. We conclude that the data confirm our previous results in nonthymectomized BM recipients--i.e., PTCs initiate antihost reactivity in MHC fully allogeneic BMT--and PTC commitment is thymus/thymus factor independent. These conclusions are discussed with regard to the problems of MHC allogeneic clinical BMT.

Animals↗
PubMed1985

Selective antilymphocyte sera (SAL) in bone marrow transplantation. I. In vitro characterization of antihuman SAL and the development of absorption procedures using cultured cell lines.

In experimental animals, graft-versus-host reactions can be prevented, even in fully MHC-allogeneic bone marrow transplantation (BMT) by in vitro elimination of mature T cells and their committed precursors from donor bone marrow with a selectively lymphocytotoxic heterologous antiserum. Application of this concept to clinical BMT has previously been hampered by the lack of antibodies of appropriately selective specificity. We describe here the production and characterization of highly selective lymphocytotoxic antisera against mature human T cells and lymphoid precursors using cultured cell lines.

Absorption↗
PubMed1985

MHC class II antigen expression on the various cells of normal and activated isolated pancreatic islets.

It is the aim of this study to characterize and quantify the cells within isolated rat islets that express MHC class II antigens. A set of five monoclonal antibodies and two polyclonal antisera of defined specificity were used in combination with a newly devised procedure for three-dimensional immunofluorescence evaluation of intact islets. It is shown that in addition to passenger cells, such as lymphocytes, macrophages, and dendriticlike cells, vascular endothelial and endocrine cells are also capable of expressing class II antigens. This expression is strongly influenced by in vitro culture, pregnancy, streptozotocin-induced diabetes, transplantation trauma, and alloantigenic stimuli. The possible role of the above cells in antigen presentation related to islet transplantation is discussed.

Animals↗
PubMed1985

Magnetic albumin/protein A immunomicrospheres. II. Specificity, reproducibility, and resolution of the magnetic cell separation technique.

Magnetically responsive albumin/protein A immunomicrospheres (MIMS) were prepared by reacting a mixture of albumin, iron oxide, and protein A in a two-phase emulsion coagulation procedure. The protein A ligand permits strong affinity binding of the monoclonal anti-HLA BW6 antibody to the 500-nm MIMS in a one-step process. HLA BW6+ and BW4+ human peripheral blood lymphocytes and mixtures of both were incubated with these MIMS. The findings obtained after only one run in a magnetic field were as follows: depletion of 98.6 +/- 0.9% of the target cells when 2 mg MIMS/10(6) cells were used, unspecific trapping of 5.9 +/- 2.5% of the nontarget cells from cell mixtures, and effective separation of cell populations as small as 1-0.1%. Thus, using albumin/protein A MIMS, the magnetic cell separation technique is simple, rapid, and highly sensitive.

Albumins↗
PubMed1984

Magnetic albumin/protein A immunomicrospheres. I. Preparation, antibody binding capacity and chemical stability.

We describe a method of preparing small magnetic microspheres of albumin/protein A, uniform in size, at 200, 300 or 500 nm. It is shown that, independent of size, the microspheres always carry iron peripherally in their matrix and are thus magnetically responsive. A quantitative antibody binding capacity of 82 micrograms/mg microspheres was established for the 500 nm microspheres. The microspheres are stable in most commonly used buffers over a pH range of 2.5-9.2, but are appreciably unstable in such concentrated denaturing agents as 3 M TCN-, 6 M guanidine, or 8 M urea (loss of antibody binding capacity, 30% for TCN- and 70% for urea).

Antibodies, Monoclonal↗
PubMed1984

Tracheal transplantation. I. The immunogenic effect of rat tracheal transplants.

To clarify contradictory information in the literature about the immunogenic effect of the trachea, tracheal transplantations were performed orthotopically and heterotopically in two combinations of inbred rat strains. In all in vivo experiments it was possible to demonstrate a considerable systemic immunisation by transplantation antigens. There were no indications of even slight organospecific immunogenicity of the trachea. Thus, the trachea is subject to the same immunological laws for transplantation as all other tissues.

Animals↗
PubMed1984

Immunosuppression by cytostatic drugs?

In the present study, an attempt was made to characterize the immunomodulating abilities of the cytostatic drugs cyclophosphamide, ifosfamide, vinblastine, vincristine, procarbazine, dacarbazine, 6-mercaptopurine, methotrexate, 5-fluorouracil and adriamycin in a defined experimental model. Varying combinations of drug plus transplantation alloantigen, (C3H-lymphocytes) were injected into Balb/c mice at different time intervals in vivo. The resulting T-effector cell reactivity was determined in vitro with the microcytotoxicity assay on day +5 for primary (1 degree) and day +7 for secondary (2 degrees) sensitized mice. According to the type of drug (alkylating agent vs. vinca alkaloid vs. antimetabolite vs. cytostatic antibiotic), the dosage (20% LD50 vs. 60% LD50), the state of sensitization (1 degree vs. 2 degrees sensitized recipients), and the time of drug application in relation to the antigen treatment on day 0 (in varying steps from day -6 to day +4), so-called "pharmacon-antigen-variation-effects" (PAVE) were established for each of the investigated drugs in form of reaction profiles. The results were as follows: For almost all substances, characteristic reaction profiles involving immunostimulation and/or immunosuppression could be established. Similarities in the profiles of different substances made it possible to classify the drugs according to different reaction types. The reaction type however is not definitely correlated to the biochemical mechanism of drug action. The PAVE are decisively influenced by some of the biological parameters, such as the time of drug application in relation to the antigen treatment and the state of sensitization but relatively little by the dosage of the drug. Considering the different processes occurring during primary and secondary immune responses, the PAVE may give hints for a distinct manipulation of the immunoregulation and thus information on the immunobiological mechanism of drug action.

Animals↗
PubMed1984

Tracheal transplantation. II. Influence of genetic difference and degree of sensitization on reactions to the tracheal transplant.

To determine what influence the extent of genetic difference and degree of presensitization exercise on reactions to tracheal transplants, orthotopic tracheal transplantations were performed in 189 rats. In groups with minor genetic differences (non-RT1-different combination) and major genetic differences (RT1-different combination), the survival rates were significantly lower in comparison with syngeneic controls. In both strain combinations, presensitization prior to orthotopic tracheal transplantation led to significantly lower survival rates. The survival times of the RT1-different strain combination were obviously shorter than those of the non-RT1-different strain combination. Therefore, the degree of histo-incompatibility and presensitization, detectable only and purposively variable in investigations on inbred strains, strongly influences the reactions to a tracheal transplant. Indications of an organospecific antigenicity of the tracheal transplant have not been found. Thus, the trachea is subject to the same immunological laws for transplantation as all other tissues.

Animals↗
PubMed1984

HLA typing of nonviable tissues with a multiple microabsorption method.

HLA typing is usually performed by directly measuring complement-dependent cytotoxicity on viable peripheral blood lymphocytes as target cells. To overcome the limitations inherent to viable targets, absorption inhibition techniques have been developed. The main drawbacks of most of these techniques are, however, that they are not very feasible and require relatively large amounts of absorbing material and rare antisera. Therefore, we adjusted the multiple microabsorption method (MMA) and tested simultaneously for 16 HLA specificities of the A, B, and C locus on 6 different nonviable tissues. The results of the MMA, when compared with those of the usual microlymphocytotoxicity test (LCT) that was run in parallel, correspond in 96% of the 28 comparable antigen pairs. Only one false negative and no false positive result was found. The absorbing quality of the individual organs differed, as was to be expected: lymph node and spleen rank on the top, followed by liver and kidney, whereas brain and muscle show several negative reactions. Altogether, the MMA proves to be a reliable and practical method for typing nonviable tissues, eg, in hematological diseases or in certain forensic situations.

Brain↗
PubMed1983

Increase of MLC sensitivity by elimination of a non-adherent responder cell subpopulation with anti-macrophage serum.

A specific rabbit anti-rat macrophage antiserum (SAM) was prepared with a cytotoxic reactivity pattern complementary to that of a specific anti-lymphocyte serum. This was used to characterise adherent and non-adherent spleen cell subpopulations in mixed lymphocyte cultures. Adherent SAM+ cells reacted as accessory cells whereas non-adherent SAM+ cells were suppressors. Selective elimination thus achieved resulted in a highly significant increase of MLC reactivity in certain strain combinations and in conversion from non-reactivity to reactivity in others.

Animals↗
PubMed1982

Neutrophil granulocytic cell antigen defined by a monoclonal antibody--its distribution within normal haemic and non-haemic tissue.

Monoclonal antibodies were raised against normal human bone marrow cells. One of the antibodies obtained, monoclonal antibody 3C4 (MA 3C4), the subject of this paper, was characterised by immunofluorescence studies with viable normal peripheral blood and bone marrow cells and by immunoperoxidase studies using paraffin sections. In bone marrow and peripheral blood MA 3C4 reacts selectively with cells of late neutrophilic granulopoiesis (myelocytes, metamyelocytes, and neutrophilic granulocytes). Cells of erythropoiesis, thrombopoiesis and lymphopoiesis are negative. In lymph node and spleen only neutrophils react with MA 3C4. In non-haemic tissue reactivity was seen with epithelial cells of a variety of different gland ducts. Thus the antigen detected by MA 3C4 can serve as a marker for neutrophil differentiation in normal haemopoiesis and as a marker for ductal epithelial cells of a variety of organs within non-haemic tissue. The antigen is formalin-resistant and can be detected in paraffin sections. The antibody thus appears to be a valuable reagent for both haematological research and for routine pathology.

Antibodies, Monoclonal↗