Disease modifying activity of HWA 486 in rat adjuvant-induced arthritis.

HWA 486 was investigated for its ability to modify the development of adjuvant-induced polyarthritis in Lewis rats. HWA 486 (20 mg/kg/day p.o.), dosed for 8 or 16 days beginning with the day of adjuvant administration, significantly reduced edema, fibrinogen levels, and erythrocyte sedimentation rates (ESR) 42 days later. When HWA 486 (20 mg/kg/day, p.o.) and cyclosporin A (CsA 15 mg/kg/day, p.o.) were tested in the 8-day treatment regimen, the antiarthritic effects of HWA 486 were more sustained. Both compounds reduced the delayed hypersensitivity (DTH) response on day 9 followed by a rebound to an enhanced DTH response on day 21. The PHA-induced mitogenic response of splenocytes from arthritic rats was suppressed on day 9. Treatment with HWA 486 but not CsA restored the splenocyte response to the level of the negative controls.

Immunotherapy of Madison 109 lung carcinoma and other murine tumors using lentinan.

Lentinan was evaluated initially against the Lewis (LL) and Madison 109 (M109) lung carcinomas implanted in the footpads of syngeneic mice. Activity in these tumor models was assessed by both reduction in early tumor growth rates and increases in life span and cures, relative to untreated control mice with tumors. Lentinan given i.p. to mice bearing LL footpad tumors caused a reduction in tumor growth rate in only one of three experiments and an increase in life span of 48% at one dose level on another occasion. In contrast, lentinan given i.p. to mice bearing M109 footpad tumors was consistently curative (50 to 70%) in three experiments despite the lack of an effect upon early tumor growth rate. In subsequent experiments, syngeneic mice were implanted s.c. with M109 or LL and treated with lentinan. Although lentinan had no substantial effect upon LL, 25 to 75% of mice bearing s.c. M109 tumors were cured in three separate experiments following early treatment initiation. Delayed lentinan therapy, initiated when s.c. M109 tumors were greater than 100 mg, also resulted in complete tumor regression and cure of 29 to 63% of the mice in three experiments. Surgical adjuvant immunotherapy of s.c. M109 using lentinan also improved survival rates over those obtained using surgery alone. Mice cured of s.c.-implanted M109 using lentinan, or surgery plus lentinan, but not surgery alone, survived a rechallenge with M109. The therapeutic effects of lentinan in mice implanted s.c. with B16 melanoma were inconsistent.

BL-5255 II: effects on release and smooth muscle activity of mediators of immediate hypersensitivity reactions.

BL-5255 inhibited release of preformed mediators from passively sensitized mast cells in the rat peritoneal cavity, chopped monkey lung or human lung tissue. The compound failed to block rat cutaneous reactions elicited by histamine or serotonin. It exhibited weak to no ability, depending on the mediator employed, to block contraction of isolated guinea pig ileum or tracheal tissue. At concentrations of 1 microM or greater, BL-5255 itself was contractile to the ileum but not to the quiescent or submaximally contracted trachea. The compound relaxed spontaneously contracting rabbit jejunum muscle but at doses not likely to be achieved in vivo. Phosphodiesterase activities in extracts of rat and human lung were inhibited at concentrations greater than those required to inhibit mediator release.

BL-5255. I. Activity in animal models of immediate hypersensitivity reactions.

BL-5255 exhibited potent activity in several models of antigen-induced immediate hypersensitivity reactions in rats and guinea pigs. The compound was effective whether administered by oral or parenteral routes and in passively and actively sensitized animals. It appeared to be readily absorbed when given orally. Localized skin and bronchoconstriction reactions in rats were inhibited by the compound by oral doses at 0.014 and 1 mg/kg, respectively. BL-5255 was protective against both IgE- and IgG-mediated reactions in the rat and guinea pig. Its effectiveness versus the systemic anaphylaxis reaction in the guinea pig appears to be due to BL-5255's ability to inhibit both the IgE and IgG1 components of the reaction.

BL-5255, a tetrazolylpyrimidinone with potent oral antiallergy activity in animals.

BL-5255, 2-(2-n-propoxyphenyl)-5-(5-1 H-tetrazolyl)pyrimidin-4 (3H)-one, effectively inhibited allergic reactions in sensitized rats or guinea pigs when administered by oral or intravenous routes as the water-soluble sodium or ethanolamine monohydrate salts. In the IgE-mediated rat PCA, BL-5255 was 50 times more potent than disodium cromoglycate by intravenous administration. When administered orally in this model, BL-5255 inhibited the PCA reaction by 50% at 0.1 mg/kg. At less than 0.1 mg/kg p.o., the compound protected conscious actively sensitized guinea pigs from aerosolized antigen-induced collapse. In N. brasiliensis-sensitized rats, BL-5255 administered at 0.1--10 mg/kg p.o. inhibited antigen-induced airway constriction in a dose-related manner. BL-5255 is not a histamine or serotonin antagonist but appears to exert its antiallergic effect by inhibiting the release of mediators.

Stimulation of interferon production in mice and in mouse spleen leukocytes by analogues of BL-20803.

Various structural analogues of the interferon inducer BL-20803 exhibited close agreement between ability to stimulate interferon production in the intact mouse and in cultures of spleen adherent leukocytes.

Target cells for interferon induction by BL-20803.

The role of certain cells of the reticuloendothelial system in the interferon response of mice to the low-molecular-weight compound 1,3-dimethyl-4-(3-dimethylaminopropylamino)-1H-pyrazola-3,4-b-quinoline dihydrochloride (BL-20803) was studied. Mouse spleen adherent cells cultured in vitro with subtoxic concentrations of BL-20803 produced interferon. Adherent cells isolated from peritoneal washes were unresponsive to the compound. Treatment of mice with rabbit antiserum to mouse adherent cells suppressed interferon production by at least 65%, wheras antisera to thymocytes or to nonadherent spleen cells failed to suppress the interferon response. Pretreatment of mice with zymosan resulted in the appearance of circulating interferon in mice given 100 mg of the inducer/kg (a dosage to which they are normally unresponsive). No potentiation of the interferon response to the drug occured in immunized mice actively making a humoral or delayed-type hypersensitivity immune response. It is concluded that a specific type of cell in the mouse, the so-called "fixed macrophage," may be a major target for interferon induction by BL 20803.

Interferon inducing activities of derivatives of 1,3-dimethyl-4-(3-dimethylaminopropylamino)-1H-pyrazolo(3,4-b)quinoline and related compounds.

Syntheses and interferon inducing acitivites are reported for 137 relatives of 1,3-dimethyl-4-(3-dimethylamino-propylamino)-1H-pyrazolo[3,4-b]quinoline (1). Three different generalized synthetic schemes for the preparation of pyrazolo[3,4-b]quinolines are presented and limitations contrasted. Other heterocyclic nuclei containing the 3-dimethylaminopropylamino side chain include pyridine, quinoline, acridine, pyrazolo[3,4-b]pyridine, pyrazolo[3,4-B][1,8]naphthyridine, pyrazolo[4',3':5,6]pyrido[2,3-d]pyrimidine, dipyrazolo[3,4-b:4',3'-e]pyridine, pyrrolo-[2,3-b]quinoline, isothiazolo[5,4-b]quinoline, and pyrido[2,3-h]pyrazolo[3,4-b]quinoline. Structural requirements for interferon induction in this series are discussed and two of the more active compounds (172 and 196) are compared directly with tilorone.

In vivo and in vitro stimulation of mouse spleen leukocytes by BL-20803, a low-molecular-weight interferon inducer.

BL-20803, a low-molecular-weight compound, although able to elicit circulating interferon in the mouse, failed to protect cultured cell lines in vitro from infection by interferon-sensitive viruses. Of the tissues analyzed for interferon content after oral administration of the drug to mice, spleen and lung contained the largest amounts of the virus inhibitor. Spleen cells from such dosed animals when isolated into in vitro cultures elaborated small amounts of interferon into the culture medium. The time sequence of acquisition by spleen cells of the ability to produce interferon closely correlated with the kinetics of development of the circulating interferon response in the intact mouse. When spleen cells were separated on the basis of adherence or nonadherence to a plastic surface, the bulk of the interferon activity was found to be associated with the adherent cells. Upon exposure to BL-20803 in cell culture, adherent cells and, to a lesser extent, nonadherent cells from untreated mice were stimulated to produce interferon-like activity. The biological behavior of BL-20803 is shown to have striking similarities with that of the structurally different low-molecular-weight inducer tilorone hydrochloride.

BL-20803, a new, low-molecular-weight interferon inducer.

BL-20803 induced interferon in mice when administered via oral or parenteral routes. During multiple dosing with the drug at 48-h intervals, animals exhibited a hyporesponsive state to the third treatment. Inhibition of vaccinia virus infection was correlated with interferon induction.