Biomedical subjects
Publications and source records attributed to C B Carpenter.
In conclusion, we have demonstrated that Ag-F antigen is not present on cytotoxic splenocytes generated in vivo. Furthermore, we have preliminary evidence that mitogen- and MLR-activated T cells are both Ag-F negative and positive; however, proliferation of some Ag-F-positive precursors may be inhibited in whole lymph node populations.
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A human proximal renal tubular epithelial antigen (designated HRTE-1) was isolated and purified from a crude tubular preparation (Fx1A) by a process of salt fractionation, DEAE anion-exchange chromatography, and Sephadex G-200 gel filtration. Utilizing 125I-HRTE-1 and a rabbit antiserum specific for the proximal tubular brush border, as determined by immunofluorescent microscopy, a radioimmunoassay by competitive protein-binding was developed. HRTE-1 was demonstrated in serum and urine and in extracts of a variety of body organs. A range of concentrations for normal random urine samples and 24-hr urine excretion rates were determined. Random urine samples from 36 patients with a variety of functional and pathologic renal disorders were assayed for the HRTE-1 antigen. Twenty-three of 24 patients with either chronic nephropathy or pre-renal azotemia had normal urinary antigen concentrations, despite wide differences in urine flow rates, the degree of existing renal function, and the amount of proteinuria. Ten of 12 patients with acute tubular necrosis, however, had statistically abnormal HRTE-1 concentrations (high in eight patients, undetectable in two). These findings suggest that HRTE-1 antigen can be detected in both normal and pathologic urines, that altered antigen concentrations can be documented in at least one renal disorder, and that quantitation of HRTE-1 in urine may have clinical value as a marker of acute rubular injury.
The mechanism of cellular rejection has been analyzed. The cells infiltrating rat cardiac allografts have been recovered and identified. An important role for cytotoxic T lymphocytes in cellular rejection has been discerned. The entrapment of cytotoxic T lymphocytes within rejecting grafts is not rigorously dependent upon antigen recognition. The cellular processes by which cytotoxic T lymphocytes destroy target cells have been determined in part. Cellular levels of the 3',5' cyclic nucleotides modulate this process. Elevations in cellular levels of cyclic AMP inhibit cytotoxicity whereas increased cyclic GMP stimulates augmented cytotoxicity.
The assays of lymphocyte-mediated cytotoxicity (LMC), antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) were correlated with histopathologic criteria of refection in 35 transplant biopsies. A positive LMC was seen with 6/8 biopsies showing moderate to severe cellular rejection and in 8/17 with mild cellular rejection. Positive ADCC and/or CDC assays were associated with 14/14 biopsies containing rejection vasculitis. These results suggest that selected in vitro assays may be useful in monitoring the immunologic events occurring in the rejecting allograft.
Components of the complement system are known to play an important role in the cytolytic process and in chemotaxis of leukocytes. Cobra venom factor specifically cleaves C3 activity via activation of the alternative (properdin) complement pathway. It does not act directly on C3. If C3 is involved in tissue necrosis after ischemic injury, cobra venom factor might reduce tissue damage after acute coronary occlusion. Accordingly, in 14 control dogs occlusion of the left anterior descending artery was carried out for 24 h. Epicardial electrograms were recorded 15 min after occlusion, and 24 h later transmural specimens for creatine phosphokinase activity (CPK) and for histological analysis were obtained from the same sites. In another 14 experimental dogs, 20 U/kg cobra venom factor was given intravenously 30 min after occlusion. Serum complement levels fell within 2-4 h to <20% of normal. In the control dogs, the relationship between ST-segment elevation and CPK activity 24 h later was: log CPK = -0.06 ST + 1.48 (n = 111 specimens, 14 dogs, r = 0.77). In the experimental dogs, log CPK = -0.024 ST + 1.46 (n = 111 specimens, 14 dogs, r = 0.60), showing significantly different slopes (P < 0.001), i.e., less CPK depression for any level of ST-segment elevation. Histologically, 69 of 71 sites (97%) with ST-segment elevation exceeding 2 mV in the control dogs showed signs of necrosis 24 h later, whereas in the experimental group only 43 of 79 sites (54%) with abnormal ST-segment elevations showed signs of necrosis (P < 0.0005). At the same time, it was shown that the administration of cobra venom factor did not alter cardiac performance, collateral blood flow to the ischemic myocardium or the clotting system, but infiltration of polymorphonuclear leukocytes into the myocardium was decreased. It is concluded that cobra venom factor, by reducing the amount of C3 and C5 substrate available for chemotactic factor generation, or other as yet undefined mechanisms, protects the ischemic myocardium from undergoing necrosis, as judged by histology and local CPK activity. Hence, a new approach to limiting the extent of myocardial infarcts after experimental coronary occlusion, based upon inhibition of complement-dependent inflammatory processes, is demonstrated.
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Lymphocytotoxic antibodies (LCTAB) were sought in sera of patients with rheumatic diseases and in family members. Patients with SLE and cutaneous necrotizing venulitis and family members of JRA patients had an increased frequency of LCTAB; JRA patients and family members of SLE patients did not. The only association between LCTAB and the HLA phenotype of persons with LCTAB was a decreased frequency of LCTAB in individuals with HLA-B27.
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The preimmunization of 10(7) Brown Norway (BN) rat lymphoid cells i.v. 1 week before (Lew X BN) F1 to Lewis renal grafting causes a state of immunologic enhancement. The BN lymphoid cells responsible for producing enhancement are the same cells that are capable of stimulating Lewis T cells in one-way MLCs. Thus active enhancement requires immunity to LD antigens, since SD +, LD- BN cells do not create a vigorous enhanced state.