Recently, essential fatty acids(EFA) have started commanding clinical interest. Their vast possibilities for therapeutic use make basic knowledge of their chemical nature and physiologic significance a necessity. EFAs are important not only in
themselve
but also as precursors of other polyunsaturated fatty acids. Evening primrose extract(EPE) is a naturally occurring rich source of EFA especially linoleic and gamma-linolenic acid which are biosynthetic precursors of prostaglandine(e.g.,
prostaglandin 1
series; PGE0. So gamma-linolenic acid in the form of a particular variety of EPE has been extensively reported of value in the treatment of vrious disorders resulting from the abnormalities of EFA. However, surprisingly little has been done to
develop
and exploit EPE's immunomodulating and antitumor properties. Moreover, the mechanism of EPE action on immune function had not been elucidated. This study was designed to examine the effect of EPE on the immune functions such as, cellular and
humoral
immune response of mice, in vitro proliferation responses of lymphocytes and malignant tumor cells, lymphokine rymphokline production of lymphocytes, lymphokine-responsiveness of target cells, NK cell activities and in vivo growth of implanted
tumor
cells. EPE did not effect on Arthus reaction, but it significantly inhibited DTH-and antibody-responses againsst sheep erythrocytes. When tumor was induced by 3LL cell-implantation, the growth of implanted cells was delayed by EPE until day 4 and
then
rapid growth ensued. In vitro EPE enhanced the growth of some cell lines such as 3LL and Fsa II cells, but it significantly inhibited the proliferation of A4, EL4 and B16 cells. When effector cells were pretreated with EPE, EPE augmented the
binding
abilities of effector cells to target cells but not lytic activities of conjugated target cells. EPE also increased the DNA synthesis of mitogen activated hyman tonsillar mononuclear cells and PHA activated T cells but not highly purified,
Staphylococcus aureus Cowan 1-activated b cells and these enhanements were more prominent when EPE was added at initiation of activation. EPE also remarkably augmented Con a-induced IL2 production of T cells and slightly enhanced the
responsiveness
of
target cells to IL2. But EPE did not influence the IL6 production of B cells and responsiveness of IL6 dependent cells to specific interleukin. Taken together, the present study revealed the EPE itself has multiple effects on events controlling
immune
resposes in a dose-, time-, cells- and stimulant-dependent manner.
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