There has been interest in the potential of synthetic compounds to modify immune responses by imitation of cytokine action. Direct administration of interleukin 2 (IL-2) in conjunction with adoptive transfer of lymphokine activated killer cells has been used in the treatment of cancer, but there are toxic effects resulting from the high doses of IL-2 required. We have developed a new synthetic compound, ammonium tri-chloro(dioxoethylene-O,O'-)tellurate (AS-101), which has immunomodulating properties and minimal toxicity. The effects of AS-101 on the activation and function of immunocompetent cells have been assessed. We have found that AS-101 induces proliferation and IL-2 production by human lymphocytes in vitro, and enhances the production of IL-2 and colony-stimulating factor by mouse spleen cells. Splenocytes of BALB/c mice injected with AS-101 increased production of IL-2 and CSF in vitro in the presence of mitogen. Mononuclear cells of normal donors acquired responsiveness to recombinant IL-2 and bound monoclonal antibody to IL-2 receptor after incubation with AS-101. Splenocytes of mice treated in vivo with AS-101 expressed high levels of IL-2 receptor. The stimulation of lymphocytes by AS-101 apparently involves an increase in intracellular free calcium. AS-101 administered systemically to mice mediated antitumour effects which could be attributable to its immunomodulatory properties. In addition, AS-101 could directly enhance the ratio of OKT4 to OKT8-positive cells in cultured mononuclear cells from AIDS (acquired immune deficiency syndrome) patients. These results indicate that AS-101 is potentially useful in the treatment of clinical conditions involving immunosuppression.

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Radicals appear in many algebraic contents. For modules over a ring, they give rise to pre-torsion and torsion theories, Goldman (5), Lambek (14). In the category of groups, Kurosh, Plotkin and others have introduced radicals (6), (13), (21), but unlike the radicals in module theory these radicals are not necessarily functorial, as for example the nil radical and the Hirsch-Plotkin radical (6). The functorial method in module theory has been extended to abelian categories, Dickson (2), to the category of nilpotent groups, Hilton (8), Warfield (25), and to the category of groups, Plotkin (22), and to general categories, Wiegandt (26), Holcombe and Walker (10).

The immunomodulator AS101 has been shown to induce cell proliferation and to increase the secretion of a variety of cytokines. In the present study we evaluated the effect of AS101 on the pathogenicity of B. rodhaini infected mice. In order to clarify its mechanism of action we studied the ability of AS101 to activate neutrophils and macrophages, both of which inhibit parasite growth. More specifically, we studied the ability of AS101 to induce secretion of nitric oxide (NO). We found that AS101 protects mice from babesiosis in a time and dose dependent manner. At 10 and 20 micrograms/injection, two weeks prior to parasites, AS101 significantly increased the number of neutrophils and more than doubled the survival rate of infected mice. Similarly, at these concentrations when injected one month, or at 20 micrograms, injected 24 h before parasites. AS101 mitigated the course of infection and reduced by half the peak of parasitaemia. At 0.1 microgram/ml AS101 induced the secretion of significantly higher levels of NO in vitro than control. This was abrogated by adding the NO synthase inhibitor. NG-monomethyl-L-arginine. In vivo the antiparasitic protection of AS101 was abrogated by another NO synthase inhibitor, aminoguanidine. We found that AS101, partly by elevating levels of NO, can significantly mitigate the course of infection and thus increase survival, and may therefore be proven as an effective antiparasitic drug.

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