Immunoregulatory In vitro/In vivo Effects of 2,3-Secotriterpene Acetylhydrazone

Immunity is a defensive reaction of an organism to suppress alien bodies (antigens), such as bacteria and viruses. Natural triterpenoids and their semisynthetic derivatives have a wide range of biological activities, including effects on immune system. This study was aimed to determine immunotropic properties of the semisynthetic A-secotriterpenoid with antiviral activity-acetylhydrazone of 1-cyano-19β, 28-epoxy-2, 3-seco-2-nor-18αH-olean-3-al (ASO). The research included the study of ASO acute toxicity and its effects on humoral and cellular immunity in the local/systemic administration of the antigen and evaluation of proliferative response of mouse splenocytes in vivo and cytokine production of immunocompetent cells in vitro. ASO has been classified as a low-toxic compound (LD>1 g kg-1) having different effects on humoral and cellular immunity. ASO showed dose-dependent (1.0-100.0 mg kg-1) stimulatory effect on the formation of Plaque-forming Cells (PFC) under local/systemic immunization conditions and the inhibitory effect on the intensity of Delayed-type Hypersensitivity response (DTH). At concentrations 30 nM, ASO demonstrated in vivo inhibitory properties on production of IL-2, IL-4 and IFN-γ, while not affecting the synthesis of IFN-α. So it is concluded that, ASO is an attractive low-toxic A-secotriterpenoid with differently directed properties which suppresses the in vitro production of IL-2, IL-4 and IFN-γ cytokines, whereas in vivo this compound stimulates intensity of the humoral immune response.