Extracts from Sarcocystis gigantea macrocysts are mitogenic for human blood lymphocytes.

Extracts were prepared from macrocysts of Sarcocystis gigantea, an animal parasite, by sonication and high speed centrifugation. Mononuclear cells were obtained from the blood of 14 adults and 5 newborns and used for transformation assays. Addition of Sarcocystis extracts (equivalent to 400 micrograms protein/ml) to these cells increased the lymphocyte proliferation approximately 71 fold over the background. The control with Pokeweed mitogen (5 micrograms/ml) gave a stimulation index of 58. There was no difference in the response to the Sarcocystis extract between the lymphocytes of adults and those of newborns. This findings show that the effect of the extract is mitogenic and not due an anamnestic reaction.