Abstract
ES materials released along with the release of mf showed immunosuppression as evidenced by a decrease in T lymphocyte levels in the immunised animals. Lipid fractions of the mf associated ES materials and protein fractions of the detergent soluble materials were found to cause suppression of immune response in the host. Further study revealed that the suppression associated with the lipid fractions is actually the end result and that mf associated ES materials is actually a mixture of immunosuppressive and immunopotentiating components and the release of the components is most likely regulated.