PubMed Health⌕ Search

Biomedical subjects

W Müller-Ruchholtz

Publications and source records attributed to W Müller-Ruchholtz.

At least 127 records · Page 7Linked 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↗