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Biomedical subjects

M E Shapiro

Publications and source records attributed to M E Shapiro.

At least 37 records · Page 2Linked to original sources

Interleukin 2 receptor expression on peripheral blood lymphocytes in association with renal allograft rejection.

Periodic assay of IL-2 receptor expression on the surfaces of peripheral blood lymphocytes might provide information predictive of in vivo immunologic events. This study compares two methods of determining IL-2 receptor expression after renal transplantation in cynomolgus monkeys. The first utilized single color staining of peripheral blood mononuclear cells with mouse anti-human IL-2 receptor monoclonal antibody followed by a fluorescein-labeled goat anti-mouse IgG antibody. Epics C cell sorter windows were set to count cells of the size and granularity of normal lymphocytes. The second utilized two-color staining with fluorescein-labeled anti-IL-2 receptor antibody, combined with phycoerythrin-labeled anti-CD4 antibody or with phycoerythrin-labeled anti-CD8 antibody. Two-color staining allowed the sorter windows to be enlarged to count all mononuclear cells, regardless of size or granularity, without introducing the contaminating effects of monocytes. Data obtained from single-color staining showed no consistent or significant expression of the IL-2 receptor on peripheral lymphocytes in association with the rejection process. Data obtained from two-color staining revealed an increase of IL-2 receptor expression on peripheral T cells of at least 10% from the postoperative baseline, which preceded the creatinine rise from allograft rejection in 13 of 13 animals. Increases in IL-2 receptor expression on T cells were not specific to rejection, however. Some animals in which treatment produced a delay of rejection showed a transient rise in IL-2 receptor expression around post-transplant day 5, which was not followed by a rise in creatinine. The two-color staining technique described provides a sensitive means of detecting IL-2 receptor expression in vivo and documents the association of increases in IL-2 receptor expression on T cells with rejection.

Animals↗

Differential IL-2 receptor expression in renal allograft recipients treated with an anti-IL-2-receptor antibody.

Patients were entered into a randomized trial of prophylaxis for renal allograft rejection by the administration of an anti-human IL-2 receptor antibody, anti-Tac, during the first ten days posttransplant. Interleukin-2 receptor (IL-2 R) expression was measured using two anti-IL-2 R monoclonal antibodies (moAbs), anti-Tac and 1HT4-4H3. These two antibodies recognize closely spaced epitopes on the 55 kD chain of the IL-2 R. IL-2 R expression was examined on peripheral blood small lymphocytes in three groups of patients who received: (A) cyclosporine CsA and prednisone for baseline immunosuppression (n = 9); (B) anti-Tac with CsA and prednisone as baseline immunosuppression (n = 12); and (C) anti-Tac with azathioprine and prednisone as baseline immunosuppression (n = 5). We found that large numbers of T cells express IL-2 receptors despite the presence of anti-Tac (average of IL-2 R-positive cells at day of peak IL-2 R expression 56.0 +/- 20.8% in group A, 65.2 +/- 26.6% in group B, 21.0 +/- 7.4% in group C). IL-2 R expression did not correlate with clinical activity, and the presence or accessibility of epitopes on the same 55 kD chain varied dramatically from patient to patient.

Antibodies, Monoclonal↗

Prophylactic use of monoclonal anti-IL-2 receptor antibody in cadaveric renal transplantation.

In vivo administration of an anti-interleukin-2 (anti-IL-2) receptor monoclonal antibody is a potential new therapy for prevention of allograft rejection of a freshly transplanted organ. Such an approach is more selective than targeting all T cells, or even the CD4 or CD8 major subsets, because only the very recently activated cells should be affected. A clinical trial of anti-Tac monoclonal antibody is in progress in which 20 mg of the immunoglobulin G 2a (lgG2a) antibody is administered intravenously daily for 10 days after cadaveric renal transplantation. Combinations with and without azathioprine, and with varying doses of cyclosporine with prednisone, are being evaluated in a randomized trial. Results to date show a significant immunosuppressive effect of anti-Tac, as measured by a reduced incidence and later onset of acute rejection episodes compared with cyclosporine plus prednisone or cyclosporine plus azathioprine plus prednisone. Removal or cytodestruction of IL-2-receptor positive cells from the peripheral blood does not occur to any major degree, even though serum levels of the antibody are always detectable. In addition, functional studies of MLR, CML, and suppressor cell generation 4 days after cessation of anti-Tac administration show no significant difference between treated and control groups The effect of anti-Tac seems, therefore, to be limited to inhibition of IL-2-mediated T-cell growth during the period of administration, with recovery after a few days' lag period.

Antibodies, Monoclonal↗

The role of a primate model of renal transplantation in the development of new monoclonal antibodies.

In recent years, a detailed understanding of the cellular and molecular basis of the immune response has been achieved. These advances, coupled with the technology for producing monoclonal antibodies, have made possible to consider highly specific and potentially powerful methods of immunosuppressive treatment. This promise of potent and specific treatment has not been entirely fulfilled on clinical practice. A preclinical nonhuman primate model of renal transplantation is described. The model has been used to investigate two monoclonal anti-IL-2 receptor antibodies, one of which was found to be effective. Anti-Tac, an lgG2a mouse antihuman monoclonal antibody, prolongs graft survival in cynomolgus monkeys from 12 to 19 days. The role of such a model in bringing new monoclonal antibodies to the clinic is described.

Animals↗

Cellular control of abscess formation: role of T cells in the regulation of abscesses formed in response to Bacteroides fragilis.

Although abscesses are a major sequela of infection, little is known about which cellular events initiate and which prevent this pathologic response. These studies are the first to indicate a role for T cells in the important pathogenic process of abscess development and also in immunity to abscesses induced by Bacteroides fragilis. We have shown that T cells initiate the formation of abscesses in mice after i.p. challenge with B. fragilis. These T cells bear both Ly-1 and Ly-2 surface markers. Nude mice (which have been shown by others to have T cell or T cell precursors) are also able to form abscesses. Cyclophosphamide-treated mice (with depressed T cell function) were not capable of developing abscesses. Reconstitution with normal or nude mouse spleen cells restored this ability. However, reconstitution with anti-Thy-1.2-treated, anti-Ly-1, or anti-Ly-2-treated spleen cells (or a mixture of the two cell populations) failed to allow abscess formation after bacterial challenge. Immunity to abscesses caused by B. fragilis requires two T cells. The first Ly-1-2+ T cell has an IJ surface marker and has been shown to release a small m.w. soluble factor (ITF) that is antigen specific. Immunity to abscesses, however, depends on the interaction of ITF with a second Ly-1-2+ T cell, demonstrated in reconstitution experiments with nude mice. The data presented document a critical role for T cells in abscess induction and suggest the existence of a suppressor-like T cell circuit in immunity to abscesses.

Abscess↗

Duodenojejunostomy for the pancreaticobiliary complications of duodenal diverticulum.

A Roux-en-Y duodenojejunostomy has been used as treatment of pancreaticobiliary disease associated with duodenal diverticula in three patients with good results. This approach removes the diverticulum from the food stream, thereby solving the problems of recurrent cholangitis and pancreatitis caused by food stasis in the diverticulum, without having to excise the diverticulum or perform a gastrectomy and vagotomy.

Aged↗

A soluble suppressor T cell factor protects against experimental intraabdominal abscesses.

This paper describes a suppressor T cell factor which protects mice against intraabdominal abscesses caused by Bacteroides fragilis. This soluble cell-free factor (ITF) is derived from splenic T cells from mice immunized with capsular polysaccharide (CP) of B. fragilis. Mice receiving ITF are protected from developing abscesses caused by B. fragilis to the same degree as animals receiving intact immune splenic T cells. The factor appears to be small in molecular size as protective activity is dialyzable through a 12,000-mol wt exclusion dialysis membrane and is present in fractions intermediate between the bed and void volumes of a P2 Biogel column. The protective effect of ITF is antigen-specific to B. fragilis alone. Mice given a complex inoculum of B. fragilis, enterococcus, and another anaerobe develop abscesses even after receiving column-purified ITF. The activity of ITF also is eliminated after adsorption with B. fragilis CP coupled to sheep erythrocytes but not with an unrelated CP coupled to sheep erythrocytes. ITF, therefore, appears to have a binding site for B. fragilis CP. ITF is heat-labile and loses efficacy after protease digestion, suggesting that the active material is a protein. These studies define a suppressor cell factor with activity in a model system resembling human disease and offer promise for increased understanding of the diversity of cell-mediated immune systems.

Abdomen↗

Lyt-1 cells mediate acute murine experimental allergic encephalomyelitis.

Adult SJL/J mice were depleted of T lymphocytes and were reconstituted with Lyt-1, Lyt-2, or Lyt-1 + Lyt-2 cells. After immunization with MSCH, severe acute EAE developed in the Lyt-1- and the Lyt-1 + Lyt-2-reconstituted mice. Only 25% of the Lyt-2-reconstituted mice developed signs of EAE, and in those EAE onset was delayed. Thus, Lyt-1 cells mediate EAE in the mouse.

Acute Disease↗

Prevention of experimental allergic encephalomyelitis (EAE) in the SJL/J mouse by whole body ultraviolet irradiation.

The cellular requirements for the in vivo induction of experimental allergic encephalomyelitis (EAE) were investigated in the SJL/J mouse. Exposure of mice to whole body ultraviolet (UV) irradiation, a treatment that has been shown in other systems to interfere selectively with antigen-presenting cell function, prevented the development of clinical and pathologic signs of acute EAE. Splenic T cells from UV-treated animals did not adoptively transfer resistance to EAE, making it unlikely that UV irradiation resulted in the generation of a specific suppressor cell population responsible for protection from EAE. UV irradiation was effective in preventing EAE when administered before initial immunization; UV irradiation was ineffective in modifying ongoing EAE or in preventing relapses of EAE induced by reimmunization. In additional experiments, adult thymectomized, lethally x-irradiated mice reconstituted with syngeneic marrow cells depleted of mature T lymphocytes were found to be resistant to the induction of EAE. Susceptibility was restored by the addition of splenic T cells, demonstrating that EAE induction is T cell-dependent in the mouse. The prevention of an experimental autoimmune demyelinating disease by whole body UV irradiation suggests that interference with the function of Ia-bearing accessory cells may represent an approach for immunotherapy in autoimmune disorders.

Animals↗

Cellular immunity to Bacteroides fragilis capsular polysaccharide.

The polysaccharide capsule of Bacteroides fragilis has been shown to be important in the virulence of the organism. The capsular polysaccharide (CP) of B. fragilis has been extensively purified. Using a murine model of intraabdominal abscess formation, we have been able to demonstrate cellular immunity to the capsular polysaccharide of B. fragilis. Immunization of C57BL/10J mice with the CP over 5 wk prevents abscess formation when the mice are challenged with B. fragilis intraperitoneally. This immunity can be transferred to naive mice with spleen cells from immune animals. The immune cells bear Thy-1.2 and Ly-2.2 antigens. The immune response has been shown to be antigen specific, but not H-2 restricted. The possibility that these immune cells are suppressor T cells is discussed. The experimental system presented provides a model for the examination of the cellular interactions responsible for abscess formation and the cellular response to bacterial pathogens.

Abdomen↗

Acute aortic thrombosis in antithrombin III deficiency.

Two cases of acute aortic thrombosis, a previously unreported complication of antithrombin III deficiency, are reported. Both patients had abnormally low antithrombin III levels, which improved to normal levels with warfarin ;sodium therapy. The possibility of antithrombin III deficiency should be considered in young patients with acute arterial thrombosis.

Acute Disease↗

Ir gene control of the cytotoxic T lymphocyte response to Sendai virus: H-2k mice are low responders to Sendai.

H-2k mice generate a secondary in vitro cytotoxic T lymphocyte response to Sendai virus 20- to 100-fold weaker than those of other haplotypes tested (H-2b,d,q,s). This immune response defect maps to both H-2K and H-2D. H-2k x H-2d F1 mice (responder x nonresponder) only lyse targets that have the d allele at H-2K and/or H-2D. H-2k targets are equally lysable with anti-Sendai antibody. Furthermore, H-2k mice demonstrate normal antibody and T cell proliferation responses to Sendai virus. The Ir gene defect therefore appears to be limited to the generation of the cytotoxic T lymphocytes.

Animals↗