Active enhancement of rat cardiac allografts induced by donor specific semisoluble antigens

Active enhancement was induced in inbred rats with cardiac allografts using semisoluble antigens. The optimal time of antigen pretreatment and optimal dose of semisoluble antigens were examined. The presence of serum blocking factors in the sera of rats having had allografts for a long time was examined with a macrophage migration inhibition test and lymphocyte microcytotoxicity assay. Since the blocking factors of macrophage migration inhibition were increasing on the 7th day, that day was determined to be the optimal time of antigen pretreatment. The mean survival time (MST) of cardiac allografts in untreated rats was 17.2 +/- 7.5 days. Semisoluble antigens were administered at 2 mg/kg body weight 7 days before the graft, 4 mg/kg 7 days before the graft and 2 mg/kg divided over three days, 15, 8 and 1 day before the graft, and the MSTs of cardiac allografts of rats receiving these treatments were 71.2 +/- 39.9, 62.6 +/- 42.2 and 79.3 +/- 31.0 days, respectively. The MST in each group of the treated rats was significantly longer than that of the control group (p less than 0.01). Rejection of the allograft, however, was accelerated in a group treated with 8 mg/kg 7 days before the graft (MST: 8.4 +/- 3.2 days). Serum blocking factors were detected in the sera of approximately half of the rats having cardiac allografts which survived a long time.     

Transfer of specific immunosuppression of graft rejection using lymph from tolerant liver-grafted rats.

The effect on graft rejection of lymph from rats rendered tolerant of donor antigens by liver transplantation has been studied. Transfer, by daily intravenous injection, of lymph from PVG rats grafted with DA livers prolonged the survival of DA skin, kidney and heart grafts in normal PVG recipients. The effect was specific for the antigens of the liver donor. Suppression was short-term only; thus, after lymph injections were stopped, rejection occurred with a time course approximating a normal first-set reaction. The result suggests a reversible interference by materials in the tolerant lymph with early stages of sensitization of the recipients.     

Immunologic enhancement of rat renal allografts. III. Immunopathologic lesions and rejection in long-surviving passively enhanced grafts.

Immunologic enhancement of renal allografts from (Lewis times Brown Norway) F1 to Lewis rats was achieved by administering a single dose of antidonor serum at the time of transplantation. A series of grafts functioning for 1 to 4 months after transplantation were examined by light and immunofluorescence microscopy to evaluate the long-term protective effects of the enhancing serum and to determine if previously unobserved lesions appeared in long survivors. Despite the absence of detectable circulating cytotoxic alloantibody, long-term allografts showed necrotizing glomerular and arterial lesions which resembled those seen in acutely rejecting grafts and were compatible with humoral rejection. Thus, in this model, there is a late decline in the ability of passive enhancement to inhibit humoral rejection. Long-term grafts also developed tubular lesions with deposition of immunoglobulin and complement on the tubular basement membranes (TBM). Anti-TBM antibodies were demonstrated in recipients' sera and found to be organ specific but not major histocompatibility antigen or species specific. This tubular lesion is therefore a unique form of allograft injury in which the immune response is directed against tissue antigen(s) which are distinct from the major histocompatibility antigens that induce rejection.     

Immunosuppressive activity of serum from liver-grafted rats: in vitro specific inhibition of mixed lymphocyte reactivity by antibodies against class II RT1 alloantigens

The immunosuppressive activity of serum from PVG rats following orthotopic transplantation of DA liver has been examined in vitro. Liver grafts in this combination are never rejected, but induce a state of specific transplantation tolerance in the recipient. Serum from such tolerant animals was able to inhibit proliferation of normal PVG lymph node cells in response to DA stimulators in the mixed lymphocyte reaction (MLR); inhibition was specific for donor (DA) antigens. Interleukin-2 (IL-2) production during the MLR was also reduced. The production of anti-DA cytotoxic T cells developing in the MLR was not affected, but the total yield of such cells was reduced. Evidence was obtained that part of the inhibitory serum activity was due to IgG antibody against class II RT1a alloantigens. Thus, a purified IgG fraction retained much of the inhibitory activity which could be removed by an anti-IgG absorbent. Studies of MLR inhibition in different rat strains indicated the anti-class II specificity of the inhibitory IgG. Lymph node cells from DA-liver-grafted PVG rats responded normally against DA stimulators in vitro, and this MLR was also blocked by the inhibitory IgG. Our results suggest that anti-class II allo-antibody may play a role in immunosuppression and long-term graft survival following liver transplantation in this combination.     

Inhibition of renal sympathetic nerve traffic from cardiac receptors in normotensive and spontaneously hypertensive rats.

The reflex inhibition of the sympathetic outflow to the kidney was examined during volume load with horse plasma in 6 normotensive rats (NCR) and 6 spontaneously hypertensive rats (SRH). The rats were anesthetized with chloralose and urethane. The arterial baroreceptors were denervated. The renal nervous inhibition was mediated via the vagal nerves and was mainly due to activation of receptors in the left side of the heart. The average thresholds in mean left artrial pressure for renal nervous inhibition was 5.4 mmHg for NCR and 9.2 mmHg for SHR indicating a clear resetting of the reflex arch in the hypertensive animal: The reason is probably a decreased distensibility of the wall of the left atrium due to a chronic elevation of left atrial pressure. This resetting of the atrial receptors in the hypertensive animals is probably of importance to allow an adequate filling pressure of the hypertrophied left ventricle and might also be of importance for the reflex neural control of renal function in these animals.     

Reduced immunogenicity of long-term, passively enhanced rat renal allografts and passive transfer of graft protection

Enhancing alloantiserum was produced by immunizing male BD IX inbred rats with density gradient separated nylon-wool adherent spleen lymphocytes from male rats of the major histocompatibility complex (MHC) different inbred strain Sprague-Dawley (SD). Long-term surviving (BD IX X SD) F1 to BD IX kidney grafts were achieved by treating the recipients with 1 ml alloantiserum at the time of transplantation. After greater than 100 days 7 passively enhanced F1 kidneys were retransplanted into naive BD IX rats. Four out of 7 secondary recipients, producing only low levels of lymphocytotoxic antibodies, survived for greater than 100 days, 3/7 rats died of surgical or infection complications. Twenty-one naive BD IX recipients of normal F1 kidneys were treated with serum (1 ml i.v.) and/or spleen lymphocytes (1 X 10(7) i.v.) obtained from the long-term survivors. An indefinite graft survival was achieved in 13 out of 21 rats. After greater than 150 days 6 out of these 13 passively enhanced F1 kidneys were retransplanted into naive BD IX rats which were challenged at the time of grafting with 4 X 10(7) SD lymphocytes to elicit rejection. Six out of 6 kidneys survived greater than 150 days. Thus, the long-term survival of rat kidney allografts in this model is associated with a strong reduction of graft immunogenicity as well as the development of suppressor cells and enhancing antibodies.     

Search for latent cytomegalovirus in renal allografts.

Cytomegalovirus (CMV) infection is common after renal transplantation, and cytomegaloviruria occurs in about two-thirds of the recipients. These observations suggest that the allografts may be a site of latent infection with CMV and its reactivation may be the source of viruria. To investigate this possibility, 130 kidney specimens from 85 persons were cultured, and simultaneous explants were made of 63 of them from 50 people. No CMV was received from 33 normal kidney or cadaver donors or from 19 allograft recipients who had no evidence of posttransplantation infection with CMV. The experiment included 37 primary organ explants that yielded no evidence of latent virus. Among 33 allograft recipients with posttransplantation CMV infection, overt infectious virus was isolated from 6 of 57 allograft biopsies. All six positive specimens were from four patients, all of whom had viruria simultaneously. Organ explants from 20 of the recipients with demonstrated postoperative CMV infection, including 13 viruric patients, failed to unmask any latent CMV. Thus, allograft kidneys were infrequently infected with CMV (6%), even in patients with viruria (24%). The kidney parenchyma appears to be an uncommon site of latent CMV infection and may not be the usual source of virus in patients with viruria.     

Prolonged survival of skin allografts in rats treated with heterologous anti-skin serum

The preparation of donkey anti-rat skin γ-globulin is described. This preparation injected subcutaneously into rats caused a marked prolongation of skin allograft survival times.

Absorption experiments of the donkey anti-rat skin γ-globulin with rat liver, leucocytes, erythrocytes, serum and skin preparation as well as the lymphocytotoxic activity of the anti-epidermis serum are described. No correlation between the biological activity of the serum and its lymphocytotoxic activity could be found.

Various possibilities explaining the mode of action of the donkey anti-rat skin serum in prolonging allograft survival times are discussed.

     

Vascular rejection in cardiac transplantation. A morphological study of 25 human cardiac allografts.

Between November 1983 and January 1990 103 orthotopic heart transplants were performed at the National Hospital, University of Oslo, Norway. Twenty-two patients died. Acute and/or chronic rejection was the cause of death in nine, disseminated infection in eight, cancer in three, and cerebral haemorrhage in one of the patients. Two patients were successfully retransplanted after graft failure due to AB0 blood group incompatibility because of a communication error. One patient with a positive lymphocytotoxic crossmatch died shortly posttransplant due to acute circulatory collapse. The cumulative one- and five-year survivals were 82% and 68%. Follow-up time was 226.6 graft years, survival range from one to 2,306 days (mean 803 +/- 4.12 SEM). A total of 1,343 endomyocardial biopsies were performed, which revealed 181 acute cellular rejection episodes, and 22 biopsies revealed acute and/or chronic vascular rejection. Autopsy studies showed three general types of vascular damage: acute (necrotizing) vasculitis, atherosclerotic disease in the epicardial arteries and diffuse proliferative arteriopathy in the intramural and smaller branches. In several cases acute vasculitis was concomitant with either of the two chronic types of accelerated graft sclerosis. Tissue immunofluorescence analysis demonstrated vascular deposition of immunoglobulin and complement in acute vasculitis, indicative of humoral immunoreaction. Postoperatively early chronic vascular rejection may develop.     

Enhancement of cardiac allografts in rats at the major AbG locus. I. Synergistic effect of specific and non-specific immunosuppression.

Investigations of the specific and nonspecific immunosupression of heart transplants in rats are presented. Pretreatment of the Wistar recipient of the August heart with donor strain cellular antigen and anti-donor hyperimmune serum 11 and 10 days before transplantation caused enhancement of the heart graft in this strain combination differing in the major AgB histocompatibility locus. Combination of that protocol with non-specific immunosuppression, i.e. ATS treatment caused synergistic effect. Heart grafts in animal treated with that full protocol of biological immunosuppression survived for 50.8 days.     

Inhibition of renal sympathetic nerve traffic from cardiac receptors in normotensive and spontaneously hypertensive rats

The reflex inhibition of the sympathetic outflow to the kidney was examined during volume load with horse plasma in 6 normotensive rats (NCR) and 6 spontaneously hypertensive rats (SHR). The rats were anesthetized with chloralose and urethane. The arterial baroreceptors were denervated. The renal nervous inhibition was mediated via the vagal nerves and was mainly due to activation of receptors in the left side of the heart. The average thresholds in mean left atrial pressure for renal nervous inhibition was 5.4 mmHg for NCR and 9.2 mmHg for SHR indicating a clear resetting of the reflex arch in the hypertensive animal: The reason is probably a decreased distensibility of the wall of the left atrium due to a chronic elevation of left atrial pressure. This resetting of the atrial receptors in the hypertensive animals is probably of importance to allow an adequate filling pressure of the hypertrophied left ventricle and might also be of importance for the reflex neural control of renal function in these animals.     

Active enhancement of dog kidney allografts using ALG and donor platelets.

The results of the studies indicate that platelets can be used as donor specific antigen in protocols of "biological suppression". Administration of donor specific platelets 10 days after transplantation to unmatched mongrel dogs treated for a brief period with ALG resulted in a marked prolongation of kidney allograft survival. Acute rejection of a second kidney from an indifferent donor suggests that a state of specific unresponsiveness was achieved by recipients pretreatment with ALG and donor antigen challenge.     

供体脾细胞胸腺内注射对致敏大鼠移植心脏存活的影响

研究胸腺内耐受诱导对心脏移植存活的影响。方法ＳＤ大鼠作为供体,Ｗｉｓｔａｒ大鼠作为受体。Ａ组单做心脏移植,Ｂ组于ＨＴ前作皮肤移植致敏 ,Ｃ组在皮肤移植及ＨＴ前作供体脾细胞脾内免疫耐受诱导。结果致敏 模型能使移植排斥终点时间显著缩短,Ｃ组供心存时间显著延长并伴相应的细胞免疫排斥指标降低。