Evening star., 1938-12-09
Mice Are Immune
To Cancer Form
In Experiment
Scientists Are Told
Results Have No
Bearing on Humans
BY THOMAS r. HENRY.

ny A41oNAhc
Production of passive immunity
to a form of cancer in a warm
blooded animal was reported for
the first time to trustees of the
Carnegie Institution of Washington,
meeting here today.
This also was, it is believed, the
first report on record Of protection
against any malignant growth
brought about after the growth
itself had attained a foothold in
the body.
The immunity may depend on an
entirely new type of protective
agent, hitherto unknown In biology
or medicine, which can function
only as a part of a living cell COM
plex.
The results were hailed as far
reaching step in fundamental
cancer research, but have no bearing
whatsoever, for the present, on
treatment of malignant growths in
man.
Liver Tissue Solution Used.
The development of transplanted
leukemia in mice, 1t was reported
by a group working with DR.. E. c.
MacDowen of the institutions de-
partment of genetics, can be pre-
vented by inoculation with solu-
ton of minced liver tissue from
has been brought about by a method
developed by the Carnegie scientists
in the past four years.
Leukemia, a rare but almost in.
variably fatal disease In humans,
is characterized by an abnormal
development of one type of white
blood cell and is sometimes referred
to as cancer of the blood" Its
action is similar to that of malig-
nant tumors. DR.. MacD0Well and
his associates had previously re-
ported that when mice of a specific
strain known to be susceptible to
leukemia by heredity were inocu-
lated with standard doses Of leu
kemic blood cells. also Of a SPECIFIC
heredity strain, the disease would
develop and death follow in a pre-
clSely predlctable time.
They then found that when mice
were inoculated with a very minute
dose OF these cells, as little as one
millionth of the standard dose, a
resistance was induced to larger
doses. BY successfully giving larger
and larger substandard doses 4
point could be reached where q
susceptible mouse could resist sue
cessiully a standard dose, which Or
dinarily would have proved fatal
In short time.
Technique Difficult.
The technique of producing this
resistance was very difncult, largely
because of the difficulty of measur-
ing doses accurately. Up to this
point, however, the Carnegie scien-
fists were in a field familiar to ex-
perimental workers on animal can
Ger. It has been known for some
time that some principle of resist
ance is built up in the body by the
growth of one cancer which, with
certain types OF malignant tumors,
prevents similar growth elsewhere
in the body. Thus a form Of rat
cancer could be transplanted in the
tip OF the tail of another rat, and
allowed to develop for a few weeks
before the tip was cut OIL. From
then on 1t was impossible to trans
plant the same kind of cancer to
another part Of the body.
This induced resistance, DR.. Mac
Dowell explains in his report to the
Carnegie trustees, is an example
of active immunity. Whatever the
principle is, it must be built up by
the animals own body cells as q
response to the hostile presence
Of the malignant cells. The method
Is common in inoculationS against
various kinds of human diseases
although 1t never has been used
against any form Of human malig.
nant growth where the danger.
would be too extreme and could
not be estimated on an experimental
| basis.
The results now reported by DR.
Mcdowell and his associates con-
stitute a long step beyond this
the production of passive immunity
in which resistance to the leukemia
apparently depends altogether on
something introduced into the body
from the outside, which has been
developed by another animal, and
in the development of which the
individuals own blood cells take no
part. One of the closest analogies
is with diphtheria toxin. Ap-
parently some substance is manu-
factured in the liver cells which
acts independently against the ma
lignant cells.
Resembles Anti-Body's Work.
1t is possible, DR.. MacDowell re-
ports, first to give the ordinarily
lethal dose of leukemic cells so that
they have chance to get started,