MGN-3
is an arabinoxylane from rice bran that has been enzymatically modified
by Hyphomyeetes mycelia. It is polysaccharides that contain /3 -1.4 xylopyramose
hemicellulose. MGN-3 was offered by Daiwa Pharmaceutical Co., Ltd. Tokyo,
Japan.
2. Human Subject and Treatment protocol:
27
cancer patients participated in the study. Their age ranged between 42
- 57 years of age. Participants were given MGN-3 at dose 3 g/day for 6
months. 20 cc blood from each individual were drawn before and after treatment
with MGN-3 and NK cell activity examined at 2 weeks, 3 months and 6 months
after treatment
3.
Separation of blood Lymphocytes (PBL).
Mononuclear
cells from the subjects were separated from the fresh whole blood by ficollhypague
density gradient centrifugation (Litton Bionetics, Rockville, MD). The
lymphocyte band at the interface was collected and cells pelleted by centrifugation,
washed twice in RFIMI- 1 640 and suspended in complete medium (CM) which
consists of RPMI-1640, supplemented with 10% (v/v) fetal calf serum, 2mM
glutamine, 25 mM Hepes (pH 7.2), 50 units penicillin and 50 p g streptomycin
per ml (Grand Island Biologicals, Santa Clara, CA).
4-
NK Cell Activity:
The
most common method of assessing NK anti-Cancer activity is to use "CR-release
assay in which fixed number of Chromium 11 (CR) -labeled tumor target cells
are incubated with varying number of NK effector cells. The percent cell
mediated lyrnpholysis is calculated from the following equation:
analysis
=(Exp. Rel. - Sp. Rel / Total Rel. - Sp. Rel) x 100
Where
Exp. Rel test refers to the counts in supernatants from wells containing
effector cells. Sp. Rel is the spontaneous release in medium only, and
Total Rel. is the maximum counts obtained by lysis with detergent. Usually
four serial dilution are made of the NK effector cells and plated in quadruplicate
with the turnor targets in niicrotiter plates. In brief, 5x 10, per ml
CM, and 0.1 ml pipetted to quadruplicate wells to give and effector: Target
cell ratio of 100: 1, 50:1, 25:1 and 12: 1. Microtiter plates were then
centrifuged for 3 minutes at 500 RPM and following a 4hours incubation
at 37'C, and the supernatant were counted in a gamma counter. The percentage
of isotope released was calculated by the formula mentioned above.
Results
of this study demonstrated that:
1.
Majority of cancer patients had low basal NK cell activity (figures I -
6).
2.
Treatment with MGN-3 resulted in significant increase in NK activity as
early as 2 weeks post treatment
(figures I - 6).
3.
Further increase in NK activity was observed at 3 and 6 months.
4.
The mechanism by which MGN-3 augments NK activity through increasing NK
cell granularity
We
conclude that MGN-3 is a potent Biological Response Modifier (BRM:) as
manifested by highly increase in human NK cell activity at 2 weeks post
treatment.
The
induction of NK activity by MGN-3 may represent a new immune-therapeutic
approach for the treatment of cancer, which needs to be examined in multiple
clinical trials.
