Regulation of inducible class II MHC,costimulatory molecules,and cytokine expression in TGF-beta1 knockout renal epithelial cells: effect of exogenous TGF-beta1

As reports of mice genetically deficient for TGF-beta1 demonstrated aberrant renal class II MHC expression, we investigated inducible class II MHC expression on renal tubular epithelial cells derived from TGF-beta1 knockout (-/-) and wild-type (+/+) mice. IFN-gamma markedly upregulated class II MHC (I-A(b)) expression in both (-/-) and (+/+) tubular epithelial cells. Coincubation studies of (+/+) and (-/-) tubular epithelial cells with IFN-gamma+LPS, or pretreatment of these cells with TGF-beta1, revealed inhibition of IFN-gamma-induced I-A(b) mRNA and cell surface expression that occurred via a decrease in class II transactivator gene expression in both (+/+) and (-/-) tubular epithelial cells. In addition, ICAM-1 was constitutively expressed on both (+/+) and (-/-) tubular epithelial cells and was upregulated by IFN-gamma or IFN-gamma+LPS. ICAM-1 expression in (+/+) and (-/-) tubular epithelial cells, however, was decreased by TGF-beta1. Parallel analysis evaluating B7-1 expression detected low levels of B7-1 in unstimulated (+/+) and (-/-) tubular epithelial cells that were increased by IFN-gamma, LPS, and IFN-gamma+LPS. IFN-gamma+LPS-mediated upregulation of B7-1 was also blocked by pretreatment with TGF-beta1. Cytokine analysis detected significantly higher levels of TNF-alpha and MIP-1alpha mRNA in all treated (-/-) preparations than in (+/+) tubular epithelial cell controls. These studies demonstrate normal patterns of class II MHC, ICAM-1, and B7 expression in TGF-beta1 (-/-) tubular epithelial cells in response to IFN-gamma, LPS, and TGF-beta1. Upregulated cytokine expression at baseline and in response to proinflammatory mediators is apparent in (-/-) tubular epithelial cells, however, and suggests that dysregulation of cytokine expression in inflammatory responses may be a primary event in multifocal inflammation observed in TGF-beta1-deficient animals.     

Variation in mortality among seven hemodialysis centers as a quality indicator

OBJECTIVES: To identify patient attributes that were associated with increased mortality; variables that were associated with process of care that were correlated with mortality; and outlier centers after adjustment for patient attributes. DESIGN: Standard interviews were conducted by trained nurses with all patients. Detailed information regarding primary renal diagnosis, comorbidity, and results of laboratory tests were obtained from the medical charts. The vital status of the patients was obtained from the records of each of the centers. We used the Cox hazard method to identify variables that correlated with a 1-year mortality. Centers with observed mortality exceeding the 95% confidence interval (CI95) of the expected probability of death were marked as outliers. SETTING: Seven dialysis centers located in large teaching hospitals in Israel. PATIENTS: The current study included patients > 16 years of age who had undergone hemodialysis > 4 weeks prior to the day of data collection. RESULTS: The study included 564 patients. Significant differences were found in patient demographics and process variables among the centers. The following variables correlated with mortality; diabetes (odds ratio [OR], 2.03; CI95, 1.28-3.21); ischemic heart disease (OR, 2.2; CI95, 1.39-3.49); each year of age (OR, 1.04; CI95, 1.02-1.06); each 1 g% of albumin (OR, 0.51; CI95, 0.30-0.86). The average observed mortality in all centers was 17.4%. After adjustment for casemix, one center showed excess mortality (24% observed compared to 15% expected after adjustment for patient attributes; CI95, 6.2-23.7). CONCLUSIONS: The ability to compare mortality rates among dialysis centers to detect possible quality outliers depends on thorough consideration of patient attributes and random variation.     

Establishment and biological activity of a proliferative anti-idiotype-activated T cell line

Antisera were raised in rabbits against a monoclonal antibody (McAb 103) of C3H.SW origin which is specific to the synthetic polypeptide (T,G)-A---L and was shown to express the major idiotypic determinants of conventional anti-(T,G)-A---L antibodies. Antibodies were purified and were shown in a binding assay to recognize McAb 103 as well as C3H.SW anti-(T,G)-A---L antibodies. C57BL/6 mice were immunized with the purified rabbit anti-McAb 103 (Ra 103) and their lymph nodes were studied in a proliferation assay. Proliferation was observed in the presence of both Ra 103 and (T,G)-A---L, although the latter stimulated the cells to a lesser extent, suggesting the induction in vivo of (T,G)-A---L-specific clones in low frequency. A T cell line was established from these lymph node cells. The line is kept in continuous growth in the presence of IL-2 and periodic triggering with Ra 103. A significant proliferative response was obtained with Ra 103 only. This proliferation could be almost completely inhibited by either McAb 103 or by conventional anti-(T,G)-A---L antibodies of C3H.SW origin, indicating the cross reaction between the idiotypes expressed on the T cell line and the (T,G)-A---L-specific antibodies. No proliferation could be detected in the presence of either normal rabbit IgG or rabbit anti-mouse IgG. Thus, the T cell line TId 103 allows the analysis of the role of idiotype in T cell recognition and regulation.     

Enhancing effect of murine anti-idiotypic serum on the proliferative response specific for poly(LTyr,LGlu)-poly(DLAla)–poly (LLys) [(T,G)-A–L]

Murine anti-idiotypic serum against C3H.SW anti-poly(LTyr, LGlu)-poly(DLAla)–poly(LLys) [(T, G)-A–L] antibodies was elicited in C57BL/6 mice. The effect of the anti-idiotypes on the proliferation of primed lymph node cells was investigated. The anti-idiotypic serum stimulated the proliferative response of the (T, G)-A–L-specific lymph node cells as well as of nylon wool-enriched T cells. In the presence of suboptimal doses of (T, G)-A–L, the addition of the anti-idiotypes enhanced the proliferation to the levels obtained with the optimal dose of (T, G)-A–L itself. These results suggest the existence of shared idiotypic determinants between antibodies and the (T, G)-A–L-specific proliferative T cells.     

Analysis of the antigen specific helper T cell function and HLA-DR of Israeli patients with rheumatoid arthritis (RA)

Forty-three patients with rheumatoid arthritis (RA) were studied for their ability to respond to the synthetic polypeptide antigen (T, G)-A-L as measured by the production of a T cell helper factor by their antigen activated T cells. Sixteen patients (37%) responded to (T, G)-A-L by the production of an antigen specific helper T cell factor, a percentage not significantly different from healthy donors. The production of antigen specific T cell helper factors was affected, although not significantly, by immune modulating drugs and by the presence of rheumatoid factor in sera of patients. The high incidence of HLA-DR 4 reported for RA patients was not observed in this group of RA patients.     

Idiotype specific T-cell lines inducing experimental systemic lupus erythematosus in mice.

Immunization of mice with either antibodies bearing the 16/6 idiotype (16/6 Id) or anti-idiotypic antibodies against the 16/6 Id induces experimental systemic lupus erythematosus (SLE). We report here the establishment and characterization of 16/6 Id-specific T-cell lines from C3H.SW (H-2b) and BALB/c (H-2d) mice. Both lines proliferate specifically in response to the 16/6 Id in an H-2-restricted manner. The injection of 16/6 Id-specific T cells into syngeneic mice led to the development of experimental SLE. Furthermore, inoculation of the 16/6 Id-specific T-cell line derived from C3H.SW mice into the H-2 compatible C57BL/6 mice, which are non-responders to the 16/6 Id, induced experimental SLE. This report provides direct evidence for the role of idiotype-specific T cells in the induction of experimental SLE.     

Dichotomy between the T and the B cell epitopes of the synthetic polypeptide (T,G)-A–L

Studies with the well-characterized, synthetic, random-multichain polypeptide poly(L Tyr, L Glu)-poly(DL Ala)–poly(L Lys) (T,G)-A–L), led to the discovery of determinant-specific genetic control of the immune response, as well as to other immunological phenomena. Moreover, the tetrapeptide TyrTyrGluGlu built on the same backbone (“T-T-G-G)-A–L”) was found to represent its major B cell epitope. We have recently shown that for interaction with major histocompatibility complex class II molecules and stimulation of T cells, (T, G)-A–L requires proteolytic processing and the resulting T cell epitopes are close to the N termini of the branched polymer's side chains. Thus, we were interested to elucidate the major T cell epitope of (T, G)-A–L, by using the ordered polypeptides (T-T-G-G)-A–L and (T-G-T-G)-A–L, in which only the two internal amino acids of the tetrapeptide attached to the side chains are switched. We established T cell lines to these antigens, and found that the ordered analog (T-T-G-G)-A–L, which was defined as the B cell epitope of (T,G)-A–L, did not represent its T cell epitope, whereas (T-G-T-G)-A–L, to which only a minor anti-(T,G)-A–L Ab response was directed, was found to be its major T cell epitope. In addition, there was no cross-reaction between (T-G-T-G)-A–L and (T-T-G-G)-A–L at the T cell level, similar to the lack of cross-reaction of their antibodies. Analysis of the repertoire of the T cell receptors used by these lines revealed that the (T,G)-A–L and the (T-T-G-G)-A–I specific T cell lines were not restricted in their Vα and Vβ TCR usage, whereas the (T-G-T-G)-A–L-specific line was restricted by both Vα and Vβ T cell receptor gene products. This difference might be due to the thymus-independent characteristics previously described for the latter antigen.     

Genetic regulation of delayed-type hypersensitivity responses to poly (Tyr,Glu)-poly(DLAla)--poly(Lys): expression of the genetic defect in the induction and manifestation phases in H-2s and H-2f mice.

The genetic defect of H-2s and H-2s non-responder mouse strains in both the induction and manifestation phases of delayed-type hypersensitivity (DTH) responses to poly(LTyr,LGlu)-poly(DLAla)--poly(LLys)[(T,G)-A--L] was analysed. Utilizing an in vitro system to activate DTH effector T cells, we observed that non-adherent T cells of (H-2f X H-2b) F1 or (H-2s X H-2b)F1 responder mice, could not be activated on antigen bearing adherent cells of H-2f or H-2s haplotypes. On the other hand, these T cells were effectively sensitized on adherent cells derived from either F1 or parental (H-2b) responder mice. These results indicate that in these mouse strains the genetic defect, in the induction phase of DTH, is expressed at the level of the antigen presenting cell. In subsequent experiments, we were able to "correct' the non-responsiveness of H-2s recipients by transfer of educated and irradiated (H-2s X H-2b)F1 T cells together with normal F1 adherent cells. Normal non-adherent and nylon wool enriched T cells failed to restore these responses. Similarly, antigen-pulsed F1 irradiated peritoneal exudate cells could stimulate DTH responses in SJL recipients of (SJL X C57BL/6)F1 (T,G)-A--L educated cells. The genetic defect of H-2s mice in the manifestation phase of the DTH reaction is thus also expressed on the antigen presenting cell.     

Lack of interferon-induced transfer of viral resistance against murine leukemia virus or poliovirus in cocultivated cells

It has recently been reported that there can be a transfer of the interferon (IFN)-induced viral resistance between cocultivated animal cells. However, in those systems the challenge virus was capable of replicating in both cell types. A more convincing conclusion could be obtained if the infecting virus could not replicate in the cell type which is homologous to the species of IFN that is added to the cultures. An inhibition of the yield of this virus would indicate that there was a transfer of the antiviral state from one cell species to another. In cocultivated mouse and human cells, a murine ecotropic type-C virus can only multiply in the mouse cells whereas poliovirus will only replicate efficiently in the human cells. It is clearly evident from this study that only homologous but not heterologous fibroblast IFN is capable of inhibiting the replication of either of these viruses in various combinations of cocultivated cells.