
2371. participation of 7s and 19s antibodies in enhancement and
resistance to methylcholanthrene-induced tumours
serum factors responsible for enhancement
and resistance to methylcholanthrene-
induced tumors in a syngeneic system in mice
were studied.  they were found to be
part of the serum immunoglobulin system.
the active components of specific anti-
tumor serum were always contained in the
7s (y-2) and 19s (y-1m) fraction, while
no activity was detected in the 4s fraction.
in sera which in the given dose enhanced
growth of the tumor graft, enhancing activity
was present in both the 7s and 19s
fraction of the serum and was higher in the
former.  in sera which in the given dose
influenced the interaction of the organism with
the tumor by producing resistance
to the tumor graft, both fractions were again
active, the activity of fraction 19s
being higher than that of fraction 7s.
