Induction, characterization, and cell transfer of autoimmune tubulointerstitial nephritis

Autoimmune tubulointerstitial nephritis (TIN) was induced in Lewis (LEW) rats by immunization with homologous Brown-Norway (BN) rat renal basement membrane (RBM), complete Freund's adjuvant and Bordetella pertussis vaccine. The BN strain has a tubular basement membrane (TBM) antigen (Ag+) detectable by immunofluorescence which is lacking in unmodified LEW rat TBM. Development of TIN in LEW rats correlated with TBM Ag+ immunogens from homologous and heterologous RBM preparations. By day 14 after immunization TIN developed characterized by elevated serum creatinine levels and by tubular destruction with focal, circumscribed lesions containing epithelioid cells, giant cells and mononuclear cell infiltrates. Approximately 60% of the mononuclear cells bore T cell antigens with most cells expressing Ia markers. Immunofluorescence and elution studies revealed no selective IgG fixation to TBM at day 14 despite high titers of circulating alloantibody reactive with the immunizing TBM. Intravenous transfer of LNC and/or splenic cells (3.5 to 7 X 10(8)) to naive LEW rats resulted in less severe but histologically identical TIN in seven days with T cell subpopulations similar to those seen in the active model. This model strongly suggests an initiating role for cell-mediated immunity in TIN in the rat and may provide a parallel to human TIN.     

Experimental gold nephropathy in guinea pigs: detection of autoantibodies to renal tubular antigens

Renal tubular dysfunction was induced in Hartley guinea pigs by injection of sodium aurothiomalate (gold) as manifested by excretion of tubular basement membrane (TBM) antigen and renal tubular epithelial (RTE) antigen in urine and tubular proteinuria. Following the tubular dysfunction, autoimmune tubulointerstitial nephritis (TIN) and/or immune complex nephropathy (ICN) developed in a large proportion of animals. TIN was associated with anti-TBM antibodies, and the histological features were characterized by tubular lesions with interstitial mononuclear cell infiltration, destruction of tubules, and interstitial fibrosis. In ICN, the glomerular lesions consisted of partial thickening of capillary walls and mesangial cellularity, and granular immune deposits were seen in the mesangial area and on capillary walls. Furthermore, electron-dense deposits were demonstrated in the mesangial area and in the glomerular basement membrane (GBM) by electron microscopy. Anti-RTE antibodies were detected in the sera and eluates from the kidney of animals with ICN. RTE antigens were also detected in the glomerular deposits by indirect immunofluorescence using anti-guinea pig RTE antibody. These results suggest that TBM and RTE antigens released from renal tubules damaged by a direct toxic action of gold may lead to antibody formation against these antigens and induce TIN and/or ICN.     

Induction of tubular basement membrane (TBM) antigen specific suppressor T cells in BALB/c mice]

Transfer of tubular basement membrane (TBM)-primed thymocytes from BALB/c mice that had been immunized with allogeneic TBM antigen without adjuvant prevented the development of interstitial nephritis (IN) in recipient BALB/c mice that had been immunized with TBM antigen with complete Freund's adjuvant (CFA) to produce IN. TBM antigen was prepared from TBM of normal ddY mice (ddY TBM antigen). BALB/c mice were highly susceptible to IN and showed a high immune response to TBM antigen when they were immunized with TBM antigen in CFA. Development of IN in high responder BALB/c mice was clearly suppressed by transfer with ddY TBM-thymocytes. The anti-TBM antibody response and the proliferative response of splenic T cells to TBM antigen were also depressed by the transfer. The cell extract of ddY TBM-thymocytes had also suppressive activity on the development of IN and on the immune response to TBM antigen. This simple system without any adjuvant for inducing the thymocytes, which has strong suppressive activity on the development of IN and on the immune response to TBM antigen, may allow us to analyse the role of suppressor T cells in negative regulation of IN.     

Childhood membranous nephropathy, circulating antibodies to the 58-kD TIN antigen, and anti-tubular basement membrane nephritis: an 11-year follow-up

Childhood membranous nephropathy (MNP) with anti-tubular basement membrane (anti-TBM) nephritis is a rare disorder that may have extrarenal manifestations. This article describes a new case to be added to the 10 previously reported. A renal biopsy specimen from a 1-year-old white boy with nephrotic syndrome, microhematuria, and hypertension showed MNP (granular global IgG, IgA and C3, and segmental IgM and C1q) associated with hypercellularity and granular deposits of IgM and C1q in the mesangium, arteriolar IgA, and linear TBM IgG, IgA, and C3. A biopsy at age 4 years showed MNP (IgG and C3) and linear IgG and C3 along the TBM. Six months later, temporary glucosuria suggested a mild tubular dysfunction. Biopsy at age 8 years showed sclerosing MNP (IgG and C3), linear TBM IgG and C3, and chronic active tubulointerstitial nephritis (TIN). Indirect immunofluorescence showed circulating anti-TBM antibodies, and the enzyme-linked immunosorbent assay (ELISA) approach verified strong reactivity with the 58-kd TIN antigen. Despite trials with steroids, chlorambucil, azathioprine, and cyclosporine, end-stage renal disease developed by the age of 9 years. At age 10 years, the patient received a cadaveric kidney transplant. With the patient now aged 12 years, the graft is still functioning well, without any clinical evidence of disease recurrence. Neurological, ocular, and abdominal symptoms, including nonbacterial diarrhea, were observed during the follow-up period. The pathophysiology of these extrarenal symptoms remains unclear. Serotyping and genotyping of HLA antigens (A2, A10, B12, B41, DR5 [1101, 1103-4, 1106 or 1108-1113], DR6 [1303, 1312, or 1413], DRB3 [*0101 and 0201-2 or 0301], DQA1 [*0501 homozygous], and DQB1 [*0301 homozygous]) did not indicate any HLA association similar to those described previously in childhood MNP with anti-TBM nephritis (HLA-B7 in four patients, HLA-DR8 in two patients). The presented case is the fifth in the literature that displays reactivity with the 58-kd TIN antigen, and for which data on HLA antigens are reported.     

Distribution of tubulointerstitial nephritis antigen and evidence for multiple forms.

A monoclonal antibody (A8) to a basement membrane component (TIN antigen), which is associated with autoimmune tubulointerstitial nephritis, was developed and utilized to characterize tissue distribution and properties of TIN antigen by immunofluorescence microscopy and immunoblotting. Results were confirmed with polyclonal goat anti-rabbit and human autoantibodies. TIN antigen was found in basement membranes of kidney cortex, small intestines, skin, and cornea, but was not detected in the renal medulla. Within the kidney cortex proximal tubular basement membrane (TBM) showed the strongest staining. TIN antigen was also detected in Bowman's capsule, distal TBM, peritubular capillaries, and focally in the interstitium, but not in glomerular basement membrane or mesangial matrix. Immunoblotting of SDS-extracted human, rabbit, mouse, and Brown Norway rat TBM with A8 revealed predominantly a 58 kD TIN antigen; however, other reactive components were detected in minor quantities. Bovine TBM contained components of 52 kD, 45 kD and 35 kD in varying concentrations. Immunoblotting of isolated rabbit TIN antigen revealed the major 58 kD component that was characterized previously, and minor components of 300 kD, 175 kD, 160 kD and 50 kD. TIN antigen was not detected in Lewis rat TBM by immunofluorescence or immunoblotting. These studies suggest the following: 1) TIN antigen may be synthesized as a high molecular weight glycoprotein that is processed to smaller forms; 2) it may be covalently associated with other basement membrane components; 3) the antibody reactive epitope may be present on multiple TBM components; and 4) high molecular weight forms may represent aggregates of TIN antigen.(ABSTRACT TRUNCATED AT 250 WORDS)     

Role of antibodies directed against tubular basement membranes in human renal transplantation

Direct immunofluorescence studies of graft biopsies from 662 renal transplant recipients demonstrated linear IgG deposition along tubular basement membranes (TBM) in 18 cases. In ten of them, circulating anti-TBM antibodies, whose detectable levels varied from 1/4 to 1/100, were demonstrated by indirect immunofluorescence on normal human kidneys. These antibodies reacted with every human kidney tested and in two cases, it could be demonstrated that they recognized the TBM of the patient's own end-stage kidney. Hence, they reacted as autoantibodies. Circulating anti-TBM antibodies were detected within the first 6 months after transplantation, remained present for an average of 3 months, and never recurred once they had disappeared. Serial biopsies demonstrated the loss of IgG linear fixation on TBM. Neither tubular nor interstitial injury was significantly associated with the presence of anti-TBM antibodies, and the transplant survival was not different in these patients who developed anti-TBM antibodies compared to our entire population of transplant biopsies.     

Renal tubular dysgenesis and tubulointerstitial nephritis antigen in juvenile nephronophthisis

Aim: The relationship between abnormalities of tubular architecture and tubulointerstitial nephritis antigen (TIN‐ag) in juvenile nephronophthisis (J‐NPH) was evaluated. Methods: Sixteen J‐NPH patients were examined. Nephrocystin‐1, TIN‐ag, type IV collagen, Fas antigen and the C5b‐9 complement complex were stained by immunohistochemical methods. Results: Renal tubules of patients with J‐NPH showed morphological abnormalities of tubular basement membranes (TBM) and frequent apoptosis of tubular epithelial cells. Additionally, the C5b‐9 complement complex was deposited within the TBM in the absence of immunoglobulin deposition, suggesting complement‐dependent TBM injury. Localization of TIN‐ag in the TBM of J‐NPH patients disclosed a partial defect or discontinuity in 14 of the 16 patients, while type IV collagen immunoreactivity was relatively preserved. These findings suggest that tubulogenesis is disturbed during nephronogenesis in J‐NPH patients because of a defect in nephrocystin, an NPHP gene product. TBM defects induce further morphological abnormalities such as cystic dilation of tubules; as tubular function impairment advances, the incomplete tubules may be injured by C5b‐9 complement complexes, followed by apoptotic cell death. Conclusion: TIN‐ag, which is important in early nephrogenesis, lacks normal activity, and vulnerable and incomplete tubules with deficient TIN‐ag expression are formed. Removal of these defective tubules by apoptosis combined with the C5b‐9 complement complex could be the primary reason for progression to end‐stage renal disease in J‐NPH patients.     

A case of an ABO-incompatible renal transplant with abundant intratubular basement membrane immune deposits

Abstract: We present a case of a 30-year-old man who received an ABO-incompatible renal transplant from his mother in 1996 after haemodialysis for 3 years. Although his renal function was stable, a renal biopsy was performed while he was in hospital for treatment of herpes zoster in 1999. Light microscopy provided no evidence of obvious acute or chronic rejection but a double contour pattern was observed in many tubular basement membranes (TBM). Immunofluorescence microscopy revealed deposits of IgG and C3 on the TBM in the absence of glomerular deposition. Massive electron-dense deposits were observed clearly by electron microscopy within TBM, revealing splitting and lamellation. This implies that the deposits resulted from the formation of immune complexes, but not from anti-TBM antibody. Although the role of TBM deposits in tubular injury is controversial, careful observation of patients with such deposits may be required because of their potential ability to induce immune reactions.     

Experimental autoimmune glomerulonephritis induced by homologous and isologous glomerular basement membrane in Brown-Norway rats

In order to study disease mechanisms and potential forms of therapy in glomerulonephritis, a model of experimental autoimmune glomerulonephritis (EAG) has been developed in the rat. We have examined the response of Brown-Norway (BN) rats to a single i.m. injection of collagenase-solubilised homologous (Sprague-Dawley, SD) or isologous (BN) glomerular basement membrane (GBM), with and without complete Freund's adjuvant (CFA). There was a dose-dependent circulating anti-GBM antibody response to all preparations of rat GBM. Animals given either antigen alone at a dose of 2 mg/kg developed circulating anti-GBM antibodies, which reached peak values by 6 weeks (63 +/- 5% following SD GBM; 53 +/- 8% following BN GBM), but did not develop glomerular deposits of IgG or nephritis. Animals given 2 mg/kg SD GBM in CFA developed greater concentrations of anti-GBM antibody by 6 weeks (122 +/- 20%) together with linear deposits of IgG on glomerular and tubular basement membranes (TBM), albuminuria (mean 7 mg/24 h), and variable focal segmental necrotising glomerulonephritis with mild interstitial nephritis. The same dose of BN GBM in CFA produced similar concentrations of circulating antibody (144 +/- 26%), with linear deposits of IgG on GBM but rarely TBM, little albuminuria, and variable mild focal glomerulonephritis. Other strains injected with SD GBM in CFA showed a variable circulating anti-GBM antibody response, which was similar to that of BN rats in PVG and DA rats but lower in LEW and WAG rats. Linear deposits of IgG on the GBM were detected in a proportion of PVG and DA rats, but not in LEW or WAG rats.(ABSTRACT TRUNCATED AT 250 WORDS)     

Pseudotumors due to IgG4 immune-complex tubulointerstitial nephritis associated with autoimmune pancreatocentric disease

Autoimmune pancreatitis (AIP) is a mass-forming chronic fibroinflammatory condition centered on the pancreatobiliary system and characterized by predominant immunoglobulin G4 (IgG4)-positive plasma cells. Recent reports have brought to light the multiorgan involvement of this disease. We describe a series of 5 cases of tubulointerstitial nephritis (TIN) associated with AIP and characterize the clinical, pathologic, ultrastructural, and immunopathologic features of TIN. The specimens consisted of 4 biopsies and 1 nephrectomy. The average patient age was 64 years (range 45 to 78) and the male to female ratio was 4:1. All had histologic and/or clinical and radiographic evidence of AIP, mass-forming sclerosing cholangitis, or both. The clinical impression in 4 patients was a renal mass or vasculitis. Two patients had renal insufficiency. Histologic preparations revealed a dense tubulointerstitial lymphoplasmacytic infiltrate. Eosinophils were often numerous. Tubulitis and tubular injury were present, along with tubular atrophy with focally thickened tubular basement membranes (TBMs). The histologic appearance ranged from a cellular, inflammatory pattern without tubular atrophy to a striking expansive interstitial fibrosis with tubular destruction. The nephrectomy specimen demonstrated a masslike nodular pattern of inflammation with normal renal tissue elsewhere. Glomeruli were uninvolved. By immunohistochemistry or immunofluorescence, numerous plasma cells in the infiltrate were positive for IgG4. TBM granular IgG deposits, predominantly of the IgG4 subclass, were detected in 4 of 5 cases by either immunofluorescence or immunohistochemistry. By electron microscopy, corresponding amorphous electron-dense deposits were present in the TBM in these cases. This type of TIN, typically characterized by a masslike lesion consisting of a lymphoplasmacytic infiltrate with eosinophils and prominent IgG4-positive plasma cells and immune-complex deposits in the TBM, may be part of a systemic IgG4-related disease, which we term "IgG4-associated immune complex Multiorgan Autoimmune Disease" (IMAD).     

Histology of human tubulo-interstitial nephritis associated with antibodies to renal basement membranes.

Twenty-seven patients with diffuse "crescentic" glomerulonephritis (CSGN) were identified in 1,174 renal biopsies from nephritic patients. Patients were assigned to three groups on the basis of the immunofluorescent study of renal biopsy specimens and serologic findings. Group I included eight patients with antibodies to glomerular (anti-GBM) and tubular (anti-TBM) basement membranes; group II had eight patients with only anti-GBM antibodies; and group III had eleven patients with CSGN unassociated with antibodies to either GBM or TBM. Patients with anti-GBM/anti-TBM antibodies (group I) had severe tubulointerstitial (TI) nephritis, as characterized by the infiltration of polymorphonuclear leukocytes and macrophages along the TBM and peritubular vessels. In some patients, focal proliferation of epithelial cells of proximal convoluted tubules (PCT), gaps or extensive destruction of TBM, lesions in the walls of small peritubular vessels, and interstitial giant cells were also observed. Patients with anti-GBM antibodies (group II) had mild to moderate interstitial cellular infiltration and mild tubular changes. Five patients with CSGN not associated with antibodies to renal basement membranes (group III) had mild to moderate interstitial cellular infiltration and tubular changes. A sixth patient, with Wegener's disease had severe granulomatous TI lesions. The results of this study show that TI nephritis is most frequent and severe with anti-TBM antibodies are demonstrable and suggest that anti-TBM antibodies contribute to the development of TI lesions.     

Effect of antitubular basement membrane and brush border antibodies on p-aminohippurate transport in kidney

The effect of antiproximal tubule basement membrane (TBM) and brush border (BB) antibodies on p-aminohippurate (PAH) transport was evaluated in a rat model of immunologically mediated interstitial nephritis. Immunized rats developed anti-TBM antibody titers ranging from 1 to 3,072 with continuous linear IgG and interrupted C3 deposits in the TBM. Circulating anti-BB antibodies were detected in half of the immunized rats in titers ranging from 1 to 128. Heavy IgG deposition was present in the BB when circulating anti-BB antibody titers exceeded eight and proteinuria was present. When anti-TBM antibody titers were 1,024 or greater the slice-to-medium PAH concentration ratio (S/M) was significantly reduced (p less than 0.001). Combined immunofluorescent microscopy and section freeze-dry autoradiography revealed normal cellular distribution of PAH-3H in all proximal tubules except in rat microscopic foci of interstitial nephritis in which concentrative transport was absent. However, luminal secretion of PAH-3H was strikingly reduced in tubules with heavy IgG BB deposits. 3-hour PAH secretion in vivo fell significantly in rats with circulating and tissue anti-BB antibodies. Antibody inhibition of PAH transport appeared to be independent of morphologic damage. Summary: Anti-TBM antibodies were associated with decreased slice uptake of PAH-3H while anti-BB antibodies were associated with decreased luminal PAH secretion in vitro and in vivo.     

Antitubular basement membrane antibodies in renal allograft rejection.

In a patient with an episode of acute renal allograft rejection, antibodies to tubular basement membranes (TBM) were noted by direct immunofluorescence in a renal biopsy and by indirect immunofluorescence in the serum. The serum antibodies decreased gradually and became undetectable 3 months after the rejected kidney was removed. Anti-RBM antibodies eluted from the rejected kidney were capable of binding in vitro to TBM but not to glomerular basement membranes (GBM) in 39 of 40 human kidneys and various animal kidneys. The specificity was confirmed by blocking studies showing inhibition with ultrasonicated human TBM but not with GBM preparations. Passive transfer experiments showed that anti-TBM antibodies were able to bind in vivo to normal rabbit kidneys, although they could not elicit an inflammatory response. The possible mechanisms of production of anti-TBM antibodies and their potential significance in graft loss are discussed.     

Linear glomerular IgG fixation in renal allografts: incidence and significance in Alport's syndrome

Twelve of 767 renal allograft recipients developed linear fixation of IgG along the glomerular basement membrane (GBM) by direct immunofluorescence technique. This was associated with linear fixation along the tubular basement membrane in 7 of them. Circulating anti-GBM antibodies were not detected by indirect immunofluorescence or radioimmunoassay in any patient whereas anti-TBM antibodies were found in 2 of 4 with linear TBM fixation. Among the 12 patients with linear GBM fixation, 5 had Alport's syndrome; the 7 others had various renal diseases, excluding anti-GBM nephritis. Among the 767 patients, 34 had Alport's syndrome or variants (i.e., 4.5%). The incidence of linear GBM fixation is much higher in Alport's syndrome than in other renal diseases. Linear GBM fixation was not clearly related to anti-GBM antibodies and was not accompanied by significant deterioration of graft function. These findings may be relevant, however, to the missing GBM antigen in Alport's syndrome.     

Renal interstitial cell infiltration in rats induced by immune reactions around proximal tubular basement membrane

Background. Since it has been shown that the severity of tubulointerstitial nephritis (TIN) and, in particular, the degree of monocyte infiltration, correlate both with the degree of renal impairment at biopsy and with the risk of disease progression, attention has been focused on the development of experimental models of TIN. Methods. We induced TIN by injecting rats with a monoclonal antibody, R3b1 (which binds around the proximal tubular basement membrane (TBM) but not to glomeruli), and also by enhancing the host immune reactions to R3b1 bound around the TBM. Results. R3b1 was demonstrated to bind around the proximal TBM but not to glomeruli in vitro and also in vivo. The binding of R3b1 around the proximal TBM induced mild focal ED-1-positive cell infiltration in the interstitium. Enhanced host immune reaction to bound R3b1 resulted in a transient increase in the number of focally infiltrated ED-1-positive cells in the interstitium, although it shortened the period during which R3b1 was demonstrable around the TBM. There were no significant increases in immunostaining for vimentin and osteopontin, or collagen types I and IV, suggesting that, immunohistochemically, there was no tubular cell damage and no interstitial fibrosis, respectively. Light microscopy revealed focal interstitial cell infiltration, supporting the results obtained by immunofluorescence as ED-1-positive cell infiltration. Tubular cell atrophy, enlargement, and interstitial fibrosis were not observed. Conclusions. The enhancement of host immune reaction to mouse immunoglobulins, i.e., to monoclonal antibody R3b1 bound around the proximal TBM induced by two immunizations, resulted in an increased degree of focal ED-1-positive cell infiltration in the interstitium, but no demonstrable tubular cell injury or interstitial fibrosis. R3b1 did not induce progressive tubulointerstitial injury, even in rats preimmunized and booster-immunized with mouse IgG. Received: July 6, 1998 / Accepted: April 28, 2000     

Immunofluorescent deposits on the tubular basement membrane in human renal transplant

In this retrospective study, the presence of tubular basement membrane (TBM) deposits of IgG and/or C3 was demonstrated in 41 renal transplants (out of 95 studied). The follow-up of these transplants varied from 9 to 19 years. The deposits were of 'linear' type in 9 cases (circulating anti-TBM antibodies were detected in 7 cases by radioimmunoassay tests and/or indirect immunofluorescence), 'granular' type in 22 cases and 'atypical' with linear and granular segments in 10 cases. Light microscopic diagnosis was acute rejection in 26 cases (33 biopsies) associated with deposits along the TBM:linear (6 cases), granular (13 cases) and atypical (7 cases). Chronic rejection present in 15 transplants (21 biopsies) was associated with linear (2 cases), granular (9 cases) and atypical (4 cases) deposits along the TBM. Electron microscopic study of renal tubules showed altered TBM with thickening, lamellation and splitting. Electron-dense deposits were not demonstrated in cases of linear deposits. A long-term follow-up study did not show any difference in survival of transplants presenting acute or chronic rejection associated or not with TBM deposits. If we consider the outcome of the transplants with TBM deposits, those with granular type seemed to have the poorest prognosis at long term, whatever the type of rejection. In the linear TBM deposits group, all the transplant nephrectomies which occurred (7 out of 9 cases) have been performed within 5 years.     

Nephritogenicity of anti-Engelbreth-Holm-Swarm sarcoma antibody

We have examined the antibody activity and nephritogenicity of anti-Engelbreth-Holm-Swarm (EHS) sarcoma antiserum in order to analyze the pathogenesis of the EHS nephropathy which has already been reported by us. An increased amount of urine protein was not recognized in rats injected with a large quantity of anti-EHS sarcoma antiserum. In addition, rats immunized with rabbit IgG before anti-EHS sarcoma antiserum injection developed no abnormal proteinuria, despite positive fluorescent staining for rat IgG as well as rabbit IgG in the glomeruli. From these results we concluded that nephritogenic antibodies could not be produced in rabbits by immunization with EHS sarcoma, which could induce the EHS nephropathy in an active model.     

Deviation of xenogeneic immune response and bystander suppression in rats fed porcine blood mononuclear cells

Reducing or deviating xenogeneic immune response prior to xenotransplantation may enhance the efficacy of conventional immunosuppressive therapies in prolonging xenograft survival. The potential to suppress or steer immune responses by oral administration of xenoantigens was evaluated. Based on knowledge of oral tolerance, hypotheses tested were that feeding xenoantigens would inhibit cell-mediated immune response (CMIR) and production of antibodies associated with graft rejection and induce bystander suppression. DA and LEW rats, high and low responders to xenoantigens, respectively, were fed dead porcine blood mononuclear cells (PBMC) and subsequently received live PBMC and hen egg-white lysozyme (HEWL, a third-party antigen) by subcutaneous injection. Delayed-type hypersensitivity (DTH) to PBMC was an indicator of CMIR. Quantification of T(H)1 (IgG(2b)) and T(H)2 (IgG(1))-associated antibodies and their ratio measured magnitude and bias of the antibody-mediated response to PBMC and HEWL. Feeding PBMC reduced IgG(2b) antibody production by 90% (DA) and 71% (LEW) and increased IgG(1) antibodies by 116% in DA but not LEW rats (p相似文献   

Antigenic determinants of tubular basement membranes and Bowman's capsule in rats

Kidney sections from several inbred rat strains were studied with an indirect immunofluorescence technique using five different, selected rat antisera which contained antibodies against the tubular basement membrane (TBM). The sera came from transplanted animals, an apparently normal animal, and animals treated with spleen cells in complete Freund's adjuvant. Upon panel analysis, at least two different antigenic determinants were recognized on the proximal TBM: One was present in nine and one was present in seven of the 15 strains tested; both determinants appear to be expressed in most antigen-positive strains. Using kidneys from major histocompatibility complex (MHC)-congenic strains, it was shown that the TBM antigens are encoded outside the MHC region. Three sera produced variable staining of Bowman's capsule in association with the proximal TBM; two sera produced clearly discordant staining of Bowman's capsule and proximal TBM. The capsular antigens were also coded outside the MHC region. These observations suggested the existence of at least two different antigenic determinants on proximal TBM. Bowman's capsule appeared to have antigenic determinants in common with the proximal TBM as well as distinct determinants.     

Effect of recombinant interferon gamma and interleukin-2 and of a monoclonal antibody against interferon gamma on the rat immune response against heart allografts

We studied the effect of rat rec-IFN-gamma, human rec-IL-2, and an IgG1 monoclonal antibody (DB1) directed against rat IFN-gamma on allograft survival in the rat in various experimental conditions. The DB1 monoclonal antibody did not prolong heart allograft survival in the (LEW/BN)F1 to LEW combination, even when used at high doses (2 mg/rat x 9 days). Rec-IFN-gamma induced major histocompatibility antigen expression in vivo, but its administration had no effect on the graft survival either of untreated LEW recipients of (LEW x BN)F1 heart allografts or of donor blood-transfused LEW recipients. In addition, rec-IFN-gamma alone had no effect on graft survival in cyclosporine-treated rats. In contrast, rec-IL-2 shortened heart allograft survival both in untreated and in cyclosporine-treated recipients. Rec-IFN-gamma partially reversed the effects of rec-IL-2 in cyclosporine-treated rats. The data suggest that in vivo administration of IFN-gamma in allograft recipients may have a suppressor effect, in addition to the postulated augmenting effect on the immune response by increasing MHC antigen expression.