[Study of the molecular and cellular mechanisms of action of lipid immunomodulators].

Within a narrow range of low concentrations (0.03-0.12 microgram/ml) polysialogangliosides containing unsaturated fatty acids in the lipid moiety of the molecule activate in vitro the proliferation of lymphocytes, synthesis of interleukin 2 and generation of highly active natural killers which are capable (in a [51Cr] test) of killing syngeneic, allogenic and xenogeneic tumor cells growing in vitro or maintained in mice (YAC-1, K562, Mch-11, SA-1, P-815, EL-4, Ehrlich carcinoma cells). We have developed biomethodology which allows one to introduce adequate concentrations of potent polysialogangliosides and phospholipids into specific macro- and microcompartments of immune system using two essentially different carriers. In experiments on mice this procedure leads to irreversible regression of subcutaneous nodules of syngeneic leukemias and sarcomas (EL-4, YAC, SA-1, Mchs-11) and of Ehrlich carcinoma with an initial size up to 1 cm, as well as to regression or prolonged inhibition of syngeneic cancers (Lewis and AMS-1) with nodules sizes up to 4-5 mm. Added cyclophosphamide increases this effect.