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M D Pescovitz

Publications and source records attributed to M D Pescovitz.

At least 91 records · Page 5Linked to original sources
PubMed1994

Analysis of monoclonal antibodies reactive with the porcine CD4 antigen.

As result of the First International Swine CD Workshop, four monoclonal antibodies (mAb) (#002, 054, 118, and 127) clustered closely to the internal standard anti-porcine CD4 mAb, 74-12-4. To further characterize the relationship between these mAb, they were used in flow cytometry to inhibit binding of 74-12-4 to porcine lymphocytes. mAb #002 (74-12-4) and #054 (PT90) completely inhibited, while mAb #127 (10.2H2) and #118 (b38c6) partially inhibited (57% and 77% respectively), the binding of 74-12-4. Furthermore, none of the mAbs bound to a 74-12-4 negative strain of pigs. We conclude that the four mAb bind to the same, or a closely related, epitope on porcine lymphocytes.

Animals↗
PubMed1994

Analyses of monoclonal antibodies reactive with porcine CD5.

Among all monoclonal antibodies (mAbs) analyzed in the first porcine CD workshop, six mAbs showed reactivity to the porcine CD5 antigen (workshop mAbs 067, 068, 069, 070, 071 and 119). Because of lack of immunoprecipitation studies for five (067, 068, 069, 070 and 071) out of the six mAbs, only one mAb (119) could be definitely characterized as mAb against the monomeric 63 kDa porcine CD5 antigen. The five other mAbs included in this cluster are characterized by an identical labelling pattern in FCM and competition of the CD5 epitope recognized by mAb 119. These mAbs were allocated to the wCD5 subcluster.

Animals↗
PubMed1994

Analyses of monoclonal antibodies reactive with porcine CD6.

Amongst the monoclonal antibodies (mAbs) submitted to the first porcine CD workshop, two mAbs (workshop numbers 055 and 120) could be identified to recognize the porcine CD6 analogue. Both mAbs seemed to be highly T-cell specific and showed neither reactivity with cells of the myeloic lineage nor with B lymphocytes. The observed molecular mass of the antigen precipitated by mAb 120 of 110 kDa confirmed this classification. Without molecular analyses of the antigen recognized by mAb 055, but similar staining pattern in FCM compared with 120, mAb 055 was allocated to the wCD6 subcluster.

Animals↗
PubMed1994

Analyses of mAb reactive with porcine CD8.

Among all mAb submitted to the first porcine CD workshop, based on FCM analyses six mAb could be identified to recognize the porcine CD8 analogue (workshop Nos. 004, 051, 052, 053, 108 and 109). In immunoprecipitation studies three mAb (Nos. 004, 108 and 109) recognized an antigen with an apparent molecular mass of about 35 kDa under reducing conditions and about 70 kDa under non-reducing conditions. The molecular masses of the antigens recognized by the three other mAb (Nos. 051, 052 and 053) are still unknown. Epitope analyses performed by blocking experiments led to the determination of two CD8 epitopes: CD8a and CD8b. CD8a is recognized by mAb Nos. 004, 051 and 052, and CD8b by Nos. 053, 108 and 109.

Animals↗
PubMed1994

Analysis of mAb reactive with the porcine SWC1.

Among 54 mAb determined to be reactive with porcine T lymphocytes and/or activation antigens, eight mAb (workshop Nos. 005, 031, 080, 091, 092, 093, 094 and 110) derived from different laboratories grouped together in the T11 cluster and were ordered into the SWC1. One mAb (No. 111) which belong also to this group was lost during the workshop. The SWC1 antigen is a molecule expressed on the majority of leukocytes, resting T lymphocytes, monocytes and granulocytes, but not on B lymphocytes. On T lymphocytes it is down-regulated after activation. The molecular mass of the antigen is unknown. Epitope analyses revealed that seven out of the nine mAb recognized similar epitopes on the SWC1 molecule.

Animals↗
PubMed1994

Comparison of Minnesota antilymphoblast globulin and Upjohn antithymocyte globulin for induction immunosuppression of human renal allografts.

BACKGROUND: An analysis of heterologous polyclonal antisera in first renal transplants was continued after replacement of Minnesota antilymphoblast globulin (MALG) with antithymocyte globulin (ATGAM), testing the hypothesis that these are functionally equivalent drugs. METHODS: Sequential induction immunosuppression used MALG (20 mg/kg/day, n = 33) or ATGAM (15 mg/kg/day, n = 14), corticosteroids, azathioprine and cyclosporine. White blood cell, platelet, and T-cell subsets were measured. Percent of patients with and time to first rejection were determined. Anti-horse antibody was measured by enzyme-linked immunosorbent assay. Minimum follow-up after transplantation was 1 year. RESULTS: Human leukocyte antigen mismatch, peak and current panel reactive antibodies, age, gender, percent cadaver donors and diabetic recipients were similar. Depletion of CD2, CD3, CD4, and CD8 T-cell subsets and platelet and white blood cells was similar. Early renal function was better with MALG than with ATGAM (p = 0.005, ANOVA), but by 2 weeks the groups were similar. The percent of patients receiving MALG versus patients receiving ATGAM with cytomegalovirus (28 versus 50), anti-horse antibodies (50 versus 62), and rejection (58 versus 50) and the median day of first rejection (48 versus 47) were similar. Three grafts were lost. CONCLUSIONS: MALG and ATGAM are equally effective in eliminating T cells and preventing and delaying the onset of renal allograft rejection.

Adult↗
PubMed1993

IDDM patients' sera recognize a novel 30-kD pancreatic autoantigen related to chymotrypsinogen.

We have examined, by western immunoblot analysis, the sera of 16 insulin-dependent diabetes mellitus patients (IDDM) for the presence of autoantibodies against proteins extracted from islet-cell enriched preparations of normal human pancreata. A novel putative autoantigen recognized by late stage IDDM patients sera was identified, and its amino acid sequence was partially determined. Islets of Langerhans were partially purified by a modified collagenase digestion procedure, and subsequent protein extracts were fractionated by one-dimensional or two-dimensional polyacrylamide gel electrophoresis (1-D or 2-D SDS-PAGE). Immunoblot analysis revealed a 30-kD species which was recognized by 4 of 16 IDDM patients sera, but none of 16 normal sera. The 30-kD protein, appeared as a single band on 1-D SDS-PAGE, but was resolved on 2-D gel electrophoresis as several distinct protein species with different isoelectric points (pI's), ranging from 7 to 9. The amino terminal sequence of one such species was partially determined by microsequencing, and the second through the fourteenth amino acids were found to be identical to the corresponding sequence in human chymotrypsinogen. The fifteenth through the eighteenth amino acids were different from the known chymotrypsinogen sequence. This region corresponds with the site that is cleaved to activate chymotrypsinogen. Based on the size and sequence homology, this antigen appears to be related to chymotrypsinogen. We conclude that this 30-kD species may be an autoantigen in some late stage IDDM patients.

Adolescent↗
PubMed1992

Organ acceptance and rejection.

During the past year, transplantation scientists have continued the quest for their version of the Holy Grail, developing and expanding model systems aimed at improving allograft survival. The highlights include further analyses of tolerance induction by intrathymic inoculation of allogeneic tissue, the use of oral tolerance to MHC antigens to improve graft survival, and expansion of the model of bone marrow transplantation to achieve solid organ tolerance in a large animal model and humans. Immunogeneticists have provided data on improved graft survival when MHC matching was performed at the molecular level.

Animals↗
PubMed1992

An evaluation of the cyclosporine parent-compound-specific whole blood TDx assay.

The new Abbott TDx cyclosporine parent-compound-specific fluorescence polarization immunoassay (TDxP) was evaluated and compared to the cyclosporine-and-metabolites-specific TDx (TDxT) and a cyclosporine parent-compound-specific radioimmunoassay (RIA) (Sandimmun-Kit, INCSTAR). The TDxP assay was linear within the range of 31 to 1600 ng/ml (r = 0.985) with a lower limit of detection of less than 31 ng/ml. The TDxP had excellent intra- and interassay reproducibility (CV = 1.2 to 4.5) that was significantly better than that of the radioimmunoassay. 230 whole blood samples obtained from 65 kidney, 19 liver, and 8 pancreas transplant recipients were analyzed with each of the three assay methods. TDxP had a much stronger correlation with the RIA than did TDxT (r = 0.95 versus 0.83). The difference between the correlations was greatest for the liver and pancreas recipients. The mean ratio of the cyclosporine level determined by TDxP to RIA was 1.0 versus 2.4 for TDxT to RIA. The new TDxP assay provides results equal to a parent-compound-specific RIA but with the added advantages of decreased sample turn-around time and improved intra- and interassay coefficients of variation.

Cyclosporine↗
PubMed1991

Transient porphyrinemia in a liver transplant recipient.

We report a case of acquired porphyrinemia in a liver transplant recipient. Thrombosis of the portal vein and hepatic artery led to massive necrosis of the patient's first donor liver, necessitating its removal. After an 18-hour anhepatic period, a second donor liver was transplanted. During this interval, the patient was warmed with an infrared heat lamp that emitted bright visible light. Following the anhepatic period, a photodistributed cutaneous erythema was noted. The level of total serum porphyrins during the anhepatic period was significantly elevated at 1.548 mumol/L (normal, less than 0.018 mumol/L). Fractionation showed that the levels of the hydrophobic porphyrins, coproporphyrin and protoporphyrin, were elevated, while the levels of the hydrophilic porphyrins remained normal. Following the successful second liver transplantation, the patient's porphyrin levels declined. This is the first reported case of acquired porphyrinemia in a liver transplant recipient.

Child↗
PubMed1990

Characterization of a porcine CD1-specific mAb that distinguishes CD4/CD8 double-positive thymic from peripheral T lymphocytes.

Porcine peripheral T-cells bear CD4 and CD8 cell surface antigens that distinguish helper from cytotoxic T-cells. In distinction from what has been found in other species, a large percentage of peripheral T-cells simultaneously express both CD4 and CD8. Monoclonal antibody 76-7-4 was found to stain all cortical and 7 +/- 3% of medullary thymocytes, Ia+ epidermal cells (i.e. Langerhans cells), no peripheral T-cells and 50% of peripheral B-cells. The antigen detected appears analogous to human CD1. All cortical thymocytes were also stained with CD4 and CD8 mAb. Since 76-7-4 did not stain peripheral T-cells, we conclude that CD4/CD8 dual-expressing peripheral T-cells are not simply immature thymic emigrants.

Animals↗
PubMed1989

Monoclonal antibodies against porcine LFA-1: species cross-reactivity and functional effects of beta-subunit-specific antibodies.

As a first step in developing a porcine model system to study the effect of LFA-1-specific monoclonal antibodies on allograft rejection, we have identified anti-human LFA-1 monoclonal antibodies that cross-react with porcine leukocytes and have used one of these antibodies against the LFA-1 beta-subunit to purify porcine LFA-1. Immunization of Balb/c mice with the purified antigen yielded eight monoclonal antibodies directed against the beta-subunit of porcine LFA-1. These antibodies immunoprecipitated pig proteins corresponding to the human alpha-subunits of LFA-1 (CD11a), Mac-1 (CD11b) and LeuM5 (CD11c), and their common beta-subunit (CD18). Under both reducing and non-reducing conditions, the porcine beta-subunit showed a different electrophoretic mobility from that of the human beta-subunit. In addition, results of peptide mapping studies revealed structural differences between the beta-subunits of human and porcine LFA-1. The anti-LFA-1 beta-chain antibodies were found to cross-react with antigens expressed on rat, mouse, hamster, rabbit, dog, cow and human leukocytes, indicating that the beta-subunit contains highly conserved epitopes. Competitive binding studies showed that these antibodies and three anti-human LFA-1 antibodies defined at least four distinct epitopes on the porcine beta-subunit, three of which were also found on human beta-subunits. Whereas the cross-reactive anti-human beta-subunit antibody H52 profoundly inhibited mitogenic and allogenic stimulation of porcine T lymphocytes as well as cytotoxic T cell and natural killer (NK) cell function, the anti-porcine LFA-1 monoclonal antibodies had very limited effect on porcine lymphocyte function. Our results demonstrate that porcine leukocytes express the LFA-1 molecule and that this antigen is involved in T cell and NK cell functions, as has previously been shown in human and murine systems. We conclude that the pig may serve as a useful model in which to test the effect of anti-LFA-1 antibodies on allograft rejection.

Animals↗
PubMed1989

Use of the circular stapler in construction of the duodenoneocystostomy for drainage into the bladder in transplants involving the whole pancreas.

The use of a circular stapler to construct a duodenoneocystostomy for exocrine drainage of transplants of whole pancreas is described herein. All but one of 15 grafts were technically successful, and the one failure was not related to the anastomosis. This method is easier than the handsewn technique we had been using, and the complication rate may be lower.

Anastomosis, Surgical↗