inosine-pranobex and Body-Weight

Multiple concomitant immune responses were assessed in individual rats following treatment with the immunoenhancing drugs, isoprinosine (5 or 50 mg/kg), NPT 15392 (0.1 or 1.0 mg/kg) and avridine (1 or 25 mg/kg), or the immunosuppressant, cyclophosphamide (75 mg/kg). Immune responses assessed in each rat were specific antibody synthesis, delayed-type hypersensitivity (DTH), natural killer cell (NKC) cytotoxicity and production of three immunoregulatory cytokines, interleukin 1 (IL1), interleukin 2 (IL2) and prostaglandin E2 (PGE2). Spleen and thymus weights and numbers of splenocytes and resident peritoneal cells were also recorded. Rats treated with isoprinosine had dose-related, significant increases in spleen weights and DTH reactions. Rats treated with NPT 15392 had significantly enhanced DTH reactions at the 0.1 mg/kg dose. Rats treated with the 25 mg/kg dose of avridine had significantly increased spleen weights, DTH reactions and NKC cytotoxicity. The effect of avridine treatment on DTH reactions and IL1 and IL2 production was inverse to the dose administered, while the NKC response was directly related to the dose. Thymus weights, antibody production and PGE2 synthesis were not significantly altered in rats treated with isoprinosine, NPT 15392 or avridine. Cyclophosphamide-treated rats had significantly reduced spleen and thymus weights, antibody synthesis, DTH reactions, NKC cytotoxicity and IL2 production, but IL1 and PGE2 synthesis were significantly elevated. It can be concluded that isoprinosine, NPT 15392 and avridine act as general immunostimulants in the rat, with avridine having the greatest effect under these experimental conditions. It also appears that these drugs are differentially immunoselective in the rat and this effect is at least partially related to the dose administered. These results could be of significance in the selective therapeutic manipulation of different arms of the immune system. Also, enhanced production of PGE2 following cyclophosphamide treatment may contribute to the immunosuppressive effects of this drug.

Topics: Animals; Body Weight; Cyclophosphamide; Diamines; Dinoprostone; Dose-Response Relationship, Immunologic; Female; Hypersensitivity, Delayed; Hypoxanthines; Immune System; Immunoglobulin G; Inosine; Inosine Pranobex; Interleukin-1; Interleukin-2; Killer Cells, Natural; Organ Size; Prostaglandins E; Rats; Rats, Inbred Strains; Spleen

Isoprinosine is a compound developed for antiviral use. The effects of isoprinosine on mouse responses to sheep red blood cells were studied over a wide range of doses, from 0.5 microgram/kg to 5 g/kg, i.p. administered at the time of i.v. immunization or as pretreatment for 7 days before antigenic stimulus. Low doses, 50 microgram/kg to 50 mg/kg, significantly increased the numbers of IgM- or IgG-spleen antibody-forming cells. Large doses, such as the LD50 (5 g/kg) or pretreatments where unable to impair mouse immune responsiveness. Isoprinosine (< 500 mg/kg/day) orally administered at time of or one day after immunization stimulated immune responses. In vitro addition of isoprinosine to spleen lymphocytes augmented PHA- or Con A-induced proliferation over a concentration range from 10 to 150 microgram/ml, whereas isoprinosine had no effect in the absence of mitogens. These data, and the lack of immunodepressing effect, suggest that there is a need for further evaluation of isoprinosine as an immunopotentiator.

Topics: Adjuvants, Immunologic; Animals; Antibody-Producing Cells; Body Weight; DNA; Inosine; Inosine Pranobex; Mice; Mice, Inbred C3H; Organ Size; Sheep; Spleen