Comparative investigations of various immunoregulatory substances in the delayed type hypersensitivity test of the mouse

Disease-modifying anti-rheumatic drugs: strategies for screening

Rheumatoid arthritis, a disease of unknown aetiology, has a multifactorial pathogenesis which may result in irreversible connective tissue destruction and loss of joint function. The search for drugs which offer more than symptomatic relief is a long term, largely unachieved aim of many pharmaceutical companies. This review briefly outlines those features of the aetiopathogenesis which appear to offer targets for therapeutic intervention and the structured strategy and test systems that can be used to detect drugs which may be capable of halting disease progression.

Lack of immunosuppression by ketoconazole and itraconazole

The antifungal drugs ketoconazole and itraconazole were evaluated for their effects in the following test systems: in vitro, phytohaemagglutinin (PHA)-induced proliferation of human peripheral blood mononuclear cells and IL-2-driven proliferation of CTLL-2 cells; in vivo, antibody response to sheep red blood cells (SRBC) and delayed-type hypersensitivity (DTH) reaction to oxazolone. At a concentration of 10 microM, ketoconazole moderately and itraconazole strongly inhibited thymidine (Thd) incorporation in human peripheral blood mononuclear cells cultured in medium supplemented with 5% human serum. Increasing the serum concentration from 5 to 20% almost completely reversed these inhibitory effects. Also, cell viability, found to be less than 15% in cultures containing 10 microM itraconazole was restored by increasing the serum concentrations in the culture medium. Similar observations were made in experiments using IL-2-stimulated CTLL-2 cells: the growth inhibition in the presence of 10 microM ketoconazole or 1 microM itraconazole could be counteracted by increased serum supplementation. In vivo, subchronic intraperitoneal dosing with 40 mg/kg ketoconazole or itraconazole to mice had no effect on the antibody response to SRBC as measured by the number of splenic IgM and IgG plaque-forming cells and did not significantly affect the DTH response to oxazolone. These data indicate that neither ketoconazole nor itraconazole exert immunosuppressive properties in vivo. Their in vitro inhibitory effects on PHA-induced lymphocyte proliferation and IL-2-dependent CTLL-2 growth are reversed by the serum supplementation to the culture medium and these activities should therefore be considered as in vitro artefacts.

Ciamexone, a highly selective immunomodulator--a tool for autoimmune diseases?

Both organ-specific diseases such as insulin dependent diabetes mellitus as well as non organ-specific disorders such as rheumatoid arthritis are thought to be autoimmune in origin. Both T-cell and B-cell mediated immune responses are involved in these diseases. More or less specific immunosuppressants are therefore widely used drugs in the treatment of autoimmune diseases which, however, suppress the immune reactions not only against autoantigens but also against foreign antigens. Cyclosporine (Cyclosporin A) has been a tremendous step forward in a more specific direction but it creates problems in the long term treatment of autoimmune diseases due to the impairment of immune reactions against foreign antigens as well as to compound specific side effects. Ciamexone, a new highly selective immunomodulator, might be an interesting new approach in the treatment of autoimmune diseases. The compound has had effect in different experimental autoimmune situations such as the diabetic BB-rat and experimentally-induced arthritis in mice or rats. The compound does not show antiproliferative activity on T-lymphocytes or B-lymphocytes. The immune response against foreign antigens, e.g. foreign major histocompatibility complex, viral or fungal antigens is not impaired. On the other hand, however, Ciamexone suppresses the antibody production in different animal systems. It is likely that Ciamexone exhibits its immunosuppressive property via the induction of regulating mechanisms. Due to its remarkably good tolerance, Ciamexone has been used in first pilot trials in different human autoimmune situations such as rheumatoid arthritis and insulin dependent diabetes mellitus.(ABSTRACT TRUNCATED AT 250 WORDS)

Studies on type II collagen induced arthritis in mice

A consistent and reproducible polyarthritis was induced in mice by immunizing them with type II collagen in Complete Freunds adjuvant (CFA) and Bacillus Calmette-Guerin (BCG) vaccine. Several inbred strains of mice were investigated for the ability to develop collagen induced arthritis (CIA). DBA/1 mice (H-2q) produced the highest incidence and the most severe arthritis of all the strains examined. Viable BCG vaccine was essential for the induction of a reproducible disease in this strain. The effects of some anti-inflammatory and anti-rheumatic compounds were examined on the developing and established lesions of CIA. These effects were determined by assessing the paw inflammation using a subjective scoring system and measuring foot weight. Furthermore, levels of serum amyloid P component (SAP) were also determined. Benoxaprofen, cyclophosphamide, indomethacin and prednisolone inhibited the paw inflammation in the developing disease whilst the anti-rheumatic compounds auranofin and D-penicillamine exacerbate the paw inflammation. Cyclophosphamide and prednisolone inhibited the established lesions but only prednisolone prevented the development of further lesions in the established disease. The SAP levels in the prednisolone treated group were also reduced. Auranofin treatment exacerbated the inflammation of both the established and the developing lesions in the same animal. D-penicillamine was inactive in the established disease.

Suppression of spontaneous insulin-dependent diabetes in BB rats by administration of ciamexone

BB rats spontaneously develop an insulin dependent diabetes which resembles in many features human type I diabetes. We have tested the effect of the immunomodulatory drug Ciamexone, a 2-cyan-aziridine-derivative, on the development of diabetes in BB rats. Ciamexone was given once daily during 6 days per week beginning with the age of 42 or 50 days up to 120 days. For comparison cyclosporin A (10 mg/kg) was applied following the same protocol. At 1 mg/kg ciamexone administration led to complete prevention of diabetes in females but was not beneficial in males. At 10 mg/kg the drug caused significant suppression of diabetes development in males but more pronounced in females. Both, a reduction of the incidence of diabetes and a delay in the onset of hyperglycaemia was observed only in females. After administration of cyclosporin A none of the animals developed diabetes. Ciamexone treatment did not affect granulocyte and lymphocyte counts and subsets in the peripheral blood except for a tendency to suppress eosinophilia. The growth of animals was not retarded. It is concluded that ciamexone seems to influence the autoimmune state of the BB rat resulting in partial suppression of the disease.

The influence on the formation of unstable haemoglobin by the immunomodulating 2-cyanaziridines azimexone and BM 41.332 in mice

Azimexone causes in mice the formation of unstable haemoglobins after a single dose of 20 mg/kg. BM 41.332, another immunomodulating drug of the 2-cyanaziridine class, induces these unstable haemoglobins only after a single oral administration of 500 mg/kg. Subsequently to the formation of unstable haemoglobins we observed a development of Heinz bodies. These effects of the 2-cyanaziridines were elicited neither by methaemoglobin formation nor by an impairment of the components protecting haemoglobin against oxidation (G6PD, catalase, glutathione). The elimination of the altered haemoglobin in the spleen could be followed by measurement of the rise in the iron content of the spleen.

Ciamexone--a new highly selective immunosuppressive compound

A local graft versus host reaction between lymphocytes of Balb-c mice and its F-1-generation CB6F1 can be induced because of differences in products of the class II of the major histocompatibility complex (Ir). In this local mixed lymphocyte reaction mainly T-helper cells and B-cells are involved. An induction of a delayed type hypersensitivity reaction with oxazolon significantly decreases the local graft versus host reaction. Cyclosporin A depresses the local graft versus host reaction and the delayed type hypersensitivity in mice whereas Ciamexone, a 2-cyanaziridine derivative, very selectively only suppresses the local graft versus host reaction and increases the delayed type hypersensitivity.