Immunopharmacological actions of Neurotropin (3): Antiallergic actions of Neurotropin

Neurotropin (NSP) is an extract isolated from vaccinia virus-inoculated and inflamed skin of rabbits. The anti-allergic actions of NSP were studied in the present paper. Death from anaphylactic shock in BALB/c mice mediated by active systemic anaphylaxis (ASA) or heterologous passive systemic anaphylaxis (PSA) was completely prevented in one out of five cases by NSP given 5000μg/animal i. v.. However in mice, NSP at a dose of 10 to 1000μg/animal ix. did not have any preventive effect on death from anaphylactic shock induced by ASA, homologous PSA, or heterologous PSA. NSP slightly inhibited histamine release from rat mast cells mediated by mouse IgE antibody, calcium ionophore A23187, or compound 48/80, but this inhibition was not in a dose-dependent fashion. NSP did not behave synergistically with isoproterenol or theophyllineinduced inhibition of mouse IgE antibody-mediated histamine release from rat mast cells. NSP did not inhibit D2O-enhanced histamine release from sensitized rat mast cells. NSP clearly inhibited antigen-induced histamine release from leukocytes of mite-sensitive patients with or without asthmatic attack. Potent inhibition was observed when leukocytes taken from patients with asthmatic attack were used. These results suggest that the anti-allergic action of NSP is not responsible for elevation of cyclic AMP levels or disruption of microtubules in target cells.