Hepatic metabolic function in patients receiving long-term methotrexate therapy: comparison with topically treated psoriatics, patient controls and cirrhotics

Standard biochemical liver function tests and the clearances of antipyrine and indocyanine green have been compared in psoriatic patients taking methotrexate, psoriatic patients on topical treatment, patient controls and patients with hepatic cirrhosis. The methotrexate-treated patients showed significant elevations in alkaline phosphatase (p less than 0.025) and gamma glutamyl transpeptidase activities (p less than 0.05) compared to topically treated psoriatics and patient controls. The clearance of antipyrine was reduced in the methotrexate treated group but not significantly (p less than 0.1 greater than 0.05). In contradistinction, the weight-adjusted clearance of indocyanine green was significantly impaired in the methotrexate group in comparison with the topically treated psoriatics (p less than 0.01). The clearance of both antipyrine and indocyanine green were markedly lowered in the cirrhotics (p less than 0.001 against all other groups). These data suggest that the serial measurement of alkaline phosphatase and indocyanine green clearance may provide a non-invasive indicator of the development and progression of methotrexate-related liver injury.

Pre-diabetes in the spontaneously diabetic BB/E rat: lymphocyte subpopulations in the pancreatic infiltrate and expression of rat MHC class II molecules in endocrine cells

Use of monoclonal antibodies specific for rat lymphocyte subsets and an anti-insulin marker has allowed us to document the following sequence of events leading to the development of clinical diabetes in this animal model. The first change observed in the pancreas is increased expression of MHC class II molecules on vascular endothelium and this precedes lymphocytic infiltration. Next, T cells of the T helper phenotype infiltrate the pancreas around blood vessels. Many of the infiltrating T cells show class II expression indicating that they are activated. A few cytotoxic and suppressor cells and B lymphocytes are also present and their numbers increase proportionately with rat age. Some macrophages are also seen. Finally, at a late stage class II MHC molecules can be detected in partially destroyed islets on beta cells which are still actively synthesising insulin. We have never observed expression of class II molecules on glucagon or somatostatin secreting cells which are invariably well preserved.

Quantitative variation in cystic fibrosis-associated proteins in cystic fibrosis patients, carriers, and controls

Serum samples from patients with cystic fibrosis (CF), obligate heterozygotes, and normal controls have been examined by isoelectric focusing (IEF). Our results suggest that cystic fibrosis protein (CFP) is a normal serum protein exhibiting quantitative variation primarily dependent on possession of the CF allele. It is concluded that detection of CFP by IEF is an inappropriate screening test for the CF gene due to lack of specificity.

Autoreactive T-cell lines specific for mouse thyroglobulin

Autoreactive T-cell specific for mouse thyroglobulin have been established and characterized. These Lyt 1+ T cells proliferated specifically in response to thyroglobulin presented by syngeneic irradiated spleen cells. The antigen-presenting cell requirements of these autoreactive T cells appeared to be the same as those for foreign antigen (PPD) reactive T cells. All lines tested required antigen-presenting cells compatible at the I-A subregion of the H-2 complex. Both T-cell types responded to antigen presented by peritoneal cells and splenic dendritic cells, but only gave optimal responses when whole spleen cells were used. The cross-reactivity patterns of responses to mouse, rat, pig and human thyroglobulins indicated that at least two different epitopes could be recognized by the autoreactive T cells. Furthermore, these epitopes appeared to be different from those recognized by the majority of serum autoantibodies to mouse thyroglobulin.

Effects of low doses of cyclophosphamide and low doses of irradiation on the regulation of induced erythrocyte autoantibodies in mice

This paper describes some of the characteristics of a suppressor cell which is capable of regulating a rat RBC-induced autoantibody response against mouse RBCs. This cell, which appears to function as an inducer of suppression on transfer to naive recipients, is sensitive to low doses of cyclophosphamide, and its generation is affected by low doses of irradiation. However, the recipients of these cells are insensitive to cyclophosphamide treatment, suppression still being induced in such animals.

Partial cross-reactivity by suppressor cells induced during different experimental autoimmune diseases

Following injection of rat red cells, mice develop anti-red cell autoantibodies and subsequently suppressor T cells specific for these. Likewise, following recovery from non-lethal malaria, they develop suppressor T cells which suppress the anti-lymphocyte autoantibodies induced by lethal malaria parasites. Neither type of suppressor cell affected non-autoantibody components of the response, nor a response to sheep red cells. However, there was variable but significant cross-suppression of the respective autoantibody responses by both types of suppressor cell. Possible reasons for this unexpected cross-reaction are discussed.

Mitogenic effects of glycolipoprotein extract from Pseudomonas aeruginosa

Glycolipoprotein extracted from the extracellular of slime of Pseudomonas aeruginosa has been tested for its ability to cause murine spleen cells to proliferate and differentiate. The extracted glycolipoprotein was found to be mitogenic for a subpopulation of murine B cells. It also caused an increase in the number of specific antibody forming cells in vitro. The activity of this extract was sensitive to low doses of cyclosporin A. These findings may be important in understanding the mechanism(s) of host resistance to this organism.

Defective regulation of erythrocyte autoantibodies in SJL mice

When SJL mice are hyperimmunized with rat red blood cells (RBC), tolerance to self is readily broken and these animals develop a high autoantibody response to their own RBC. However, these mice also fail to generate those antigen-specific suppressor cells which normally regulate this induced autoantibody response.

II. IgM-mediated enhancement: dependency on antigen dose, T-cell requirement and lack of evidence for an idiotype-related mechanism

Passive administration of monoclonal IgM anti-sheep red blood cell antibody 2 hr prior to a low dose of sheep red blood cells (SRBC) markedly enhances the specific antibody response. This IgM enhancement of the response to SRBC is highly reproducible and can furthermore be demonstrated in vitro. The time course and dose dependency of the response indicate that a critical antibody: antigen ratio is necessary for enhancement to occur. The IgM enhancement phenomenon has been demonstrated in several strains of mice, providing strong evidence against an idiotype-related mechanism.

The differential effect of 2-deoxyguanosine on concanavalin A-induced suppressor and cytotoxic activity

The effect of 2-deoxyguanosine (dGuo) on the generation in vitro of nonspecific suppressor cells in murine spleen cell cultures by concanavalin A (Con A) is examined. The experiments indicate that dGuo abrogates the generation of nonspecific suppressor activity by lectin stimulation of murine spleen cells. When comparisons were made between the effect of this nucleoside on the generation of suppressor and cytotoxic cells by Con A stimulation of murine spleen cells, it was found that dGuo only affected the generation of suppressor cells. The development of lectin-stimulated cytotoxicity was not affected by dGuo. In addition it was found that dGuo does not affect the NK activity of murine spleens.

Mechanisms of autoimmunity: a role for cross-reactive idiotypes

Ehrlich was rarely given to trivial pronouncements and his recognition of the central importance of the distinction between self and non-self by the immune system, embodied in his concept of 'horror autotoxicus'(1), is no exception. This is despite the apparent paradox of the idiotype network in which antibodies recognize self-epitopes on other antibody molecules or antigen receptors as part of the normal process of immune regulation. In this review Anne Cooke and her colleagues examine the possible factors which may contribute to the breakdown of self-tolerance and the establishment of autoimmune states.

Functional evaluation of murine allogeneic T lymphoblasts separated by Vicia villosa lectin positivity

Mixed-lymphocyte culture-stimulated cells have been fractionated by their ability to bind the lectin Vicia villosa (Vv) and assessed for their cytolytic and suppressor activity in vitro. Vv positive and negative cells were separated either by cell affinity chromatography using Vv-Sepharose 6MB chromatography or by electronic cell sorting with FITC-Vv. Both populations expressed marked cytolytic and suppressor cell activity. Thus this lectin cannot be used to discriminate between these and other functional lymphoid cell population of blastoid cells binding the FITC-Vv appears following allogeneic stimulation; treatment with the immunosuppressive drug cyclosporin A, which affects cytotoxic cells preferentially, results in a considerable reduction of the Vv positive blastoid cells.

An in vitro cytotoxicity study of aldehyde-treated pig dermal collagen

The cytotoxicity of aldehyde-treated collagen was assayed by measuring 3H-thymidine incorporation in adult human skin fibroblasts grown in tissue culture for 1 or 3 days in the presence of pig dermal collagen cross-linked with formaldehyde or glutaraldehyde. A comparison was also made with collagen preparations washed for 2 weeks either at 15 degrees throughout or partly at 15 degrees and partly at 37 degrees. Collagen treated with both formaldehyde and glutaraldehyde proved increasingly toxic with increase in the concentrations of aldehyde used. While the maximum toxic effect was observed after 1 day culture in formaldehyde-treated collagen, with thymidine uptake ranging from 4-48% of control values with 5-0.1% formaldehyde and a 15 degrees wash, the toxic effect of glutaraldehyde treatment increased with longer exposure and at 3 days thymidine uptake ranged from 3-40% of control values with 0.05-0.001% glutaraldehyde and washing at 15 degrees. Washing partly at 37 degrees significantly reduced toxicity, the differences in thymidine uptake as compared with washing at 15 degrees alone ranging from 34-50% with 1 and 0.3% formaldehyde respectively in 1 day cultures and from 14-37% with 0.02 and 0.005% glutaraldehyde in 3 day cultures. While fibroblasts actively grew and migrated when seeded on non-cross-linked collagen, only limited cell survival occurred on aldehyde-treated collagen.

Specific monoclonal IgM is a potent adjuvant in murine malaria vaccination

Recent experiments in the murine system have indicated that the passive acquisition by offspring of maternal anti-malarial IgG antibodies while conferring some degree of immunity against a primary infection, paradoxically prevents the generation of acquired immunity through vaccination. Therefore, in view of earlier findings concerning the competitive effects of specific IgM and IgG antibodies, we investigated whether specific monoclonal IgM antibodies could be used to potentiate the response to a blood-stage murine malaria vaccine. We now report that small amounts of purified monoclonal anti-parasite IgM can specifically potentiate both priming and memory cell generation in response to vaccination as evidenced by survival after infection, and that the magnitude of this effect is greater than that found with a more conventional nonspecific adjuvant (Bordetella pertussis). Additionally, in offspring of immune mothers, where vaccination is ineffective for up to 8 weeks due to the presence of maternal IgG, we have found that IgM when administered with the vaccine can completely overcome this inhibition by its adjuvant effect.

Murine T cell suppression demonstrable in the absence of cytotoxicity and the effect of Cyclosporin A on this system

In vitro culture of murine spleen cells in FCS without prior immunization or allogeneic stimulation leads to the development of spontaneous cytotoxicity. This cytotoxicity is not H-2 restricted and can affect any subsequent in vitro assays using syngeneic cells, especially if those assays include prolonged culture in FCS. Studies on murine spleen cells cultured in NMS, however, led to the detection of a suppressor system that did not display cytotoxic effects. Furthermore, it was found that this suppression, in contrast to the cytotoxicity and suppression generated during culture in FCS, was not sensitive to CYA. The suppressor cell may be an effector or an inducer of suppression and is sensitive to treatment with anti-Thy-1.2 and complement. It is suggested that some in vitro suppression is really due to cytotoxicity that may be directed toward FCS determinants adsorbed onto syngeneic targets.

Murine T cell suppression demonstrable in the absence of cytotoxicity and the effect of Cyclosporin A on this system

In vitro culture of murine spleen cells in FCS without prior immunization or allogeneic stimulation leads to the development of spontaneous cytotoxicity. This cytotoxicity is not H-2 restricted and can affect any subsequent in vitro assays using syngeneic cells, especially if those assays include prolonged culture in FCS. Studies on murine spleen cells cultured in NMS, however, led to the detection of a suppressor system that did not display cytotoxic effects. Furthermore, it was found that this suppression, in contrast to the cytotoxicity and suppression generated during culture in FCS, was not sensitive to CYA. The suppressor cell may be an effector or an inducer of suppression and is sensitive to treatment with anti-Thy-1.2 and complement. It is suggested that some in vitro suppression is really due to cytotoxicity that may be directed toward FCS determinants adsorbed onto syngeneic targets.

Direct staining of mouse T lymphoblasts with fluoresceinated Vicia villosa lectin

Fluorescein conjugated Vicia villosa (Vv) lectin was used for direct staining of the surface of viable cells of various mouse lymphocyte populations. A varying proportion of polyclonally-activated T cells expressed Vv receptor although less strongly than cells of an influenza virus-specific cytotoxic T lymphocyte (CTL) clone and blasts generated in the mixed lymphocyte reaction. Cyclosporin A (CyA) treatment markedly reduced the expression of Vv receptor following concanavalin A (Con A) stimulation by between 66% and 93% with a concurrent inhibition of blastogenesis and complete abrogation of cytolytic function. Resting mouse lymphocytes and B-cell blasts were always Vv-negative. However, non-specific suppressor factor producing non-cytotoxic T-cell lines also expressed Vv receptor as shown by the weak, but specific, surface fluorescence of EL4 and BW5147 cells stained with Vv. Vv-positive cells were not restricted to a particular Ly phenotype, Vv-positive cells being found among both Lyt 1+ and Lyt2+ MLC stimulated lymphocytes. Our data suggest that the receptor for Vv lectin cannot be regarded as an exclusive differential marker for CTL.

Newly synthesised DNA in ageing human cells in culture treated with 4-nitroquinoline-1-oxide

Two lines of normal human embryonic lung fibroblasts, MRC-5 and F2002, were serially subcultured until senescence was attained. When cells were exposed to varying concentrations of the chemical carcinogen 4-nitroquinoline-1-oxide (4-NQO), the rate of DNA synthesis (as measured by thymidine incorporation) was reduced in a dose-dependent fashion in cells from both early and late passages. While the overall amount of incorporation was considerably lower in old cells, the extent of inhibition caused by 4-NQO treatment (relative to appropriate controls) was not related to culture age. Alkaline sucrose density gradient analysis of newly synthesised DNA from cells pre-treated with 4-NQO failed to detect any significant variation in the size of labelled DNA from cells examined immediately after incubation with radioactive thymidine. The shift of this labelled material to high molecular weight in 4-NQO-treated cells also showed no age-related difference.

Antibody mediated regulation of immune responses. I. Enhancement of specific antibody responses through IgM antibodies

Injection of monoclonal IgM antibodies to sheep red blood cells (SRBC) 2 h before immunization with a low dose of antigen (Ag) specifically enhances the direct and indirect plaque-forming cell response. This enhancement was specific: the specific antigen had to be present; the plaque-forming cell (PFC) response to TNP-Ficoll- or bromelein-treated mouse red blood cells was not enhanced; the PFC response to SRBC was not enhanced by injections of monoclonal antibody to TNP. The optimum conditions for enhancement were found to be dependent on both the dose and the time of administration of antibody in relation to antigen. The possible mechanisms for this enhanced antibody response are discussed.

Independent segregation of NZB immune abnormalities in NZB x C58 recombinant inbred mice

The study of NZB x C58 recombinant inbred mouse strains has revealed independent segregation of naturally occurring thymocytotoxic antibody and Coombs' anti-erythrocyte autoantibody. The lack of concordance of either of these autoantibodies with known heavy and light chain markers suggests that the autoantibodies are produced as a result of regulatory gene defects rather than alterations of antibody structural genes. Further, lack of concordance of the various autoimmune traits with each other or with H-2 or virus expression suggests that the autoimmune phenotype is not the result of a single "autoimmunity' gene but rather the outcome of faulty regulation of a number of independently segregating genes.