[Immunomodulating activity of 1-methyl and 1-ethylascorbigens]

1-Methyl- and 1-ethylascorbigens, derivatives of indole and ascorbic acid are the vitamin C depo-forms with antitumor activity. Relation between the antitumor activity of the derivatives and their immunostimulating action was studied. The derivatives showed similar properties in vitro: they stimulated lymphocyte blast transformation, insignificantly stimulated formation of cytotoxic T-lymphocytes (CTL) in the allogenic mixed culture of lymphocytes (AMLC), inhibited cytotoxicity of natural killer cells (NKC) and had no cytotoxic action in cultures of tumors CaOv and others. In vivo 1-methylascorbigen promoted an increase in the splenocyte count in mice, stimulated 16-fold generation of CTL in AMLC of the splenocytes and retarded the growth of ACATOL tumor in thymus-free mice. 1-Ethylascorbigen had no such effects. The antitumor action of 1-methylascorbigen is likely to be associated with stimulation of CTL generation and not with the increase in the activity of NKC.