19
4. Isolysins.
Goat B which had been injected at intervals for the past three years with
citrated sheep blood was found to have developed an isolysin in its serum which
lysed the RBCs of all the different goats tested, with the aid of guinea-pig.
complement. Its own RBCs alone remained intact.
This amboceptor could not be complemented by either fresh sheep or fresh
goat serum. Horse serum however complemented it slightly. There was some-
difference noticed between the degree of lysis obtained with the RBCs of
different goats with this isolysin and guinea-pig complement, and this difference
was even more marked with horse complement. Evidently there was a difference
between the RBCs of different individuals as regards their ability to absorb this
amboceptor ; and the fact that Goat B's own RBCs were not able to absorb it at
all renders it certain that the RBCs of individuals of the same species are not
exactly alike in their reactions with lyric agents.
With heterolysins this fact has not been recorded : it is possible that a goat
injected with sheep RBCs from one sheep only would not develop a lysin potent
against the RBCs of all other sheep, but only against a certain number. Todd
and White, (Proc. Roy. Soc., B., Vol. 82, p. 416, 1910) with the unique material
at their disposal, have shown that isolysins are developed in the serum of cattle
which have been injected with the blood of other cattle, and that these isolysins are
effective against only a certain proportion of the RBCs of other individuals. By
mixing the serums of these immunised cattle they were able to obtain an isolysin
potent against the RBCs of all the cattle tested. They do not definitely state
whether the inoculations each animal received were derived from one animal only,
but presumably this was not so. As in the case of our goat, whose isolysin cannot
be complemented by goat serum, Todd and White's isolysins could not be comple-
mented by ox serum, but were well complemented by guinea-pig serum ; nor was
any isolysin effective against the RBCs of the individual from which it was.
derived.
There is a distinction between Todd and White's isolysins and ours in that
theirs were the result of the inoculation of cattle blood into cattle, irrespective, it
is true, of breed, whereas ours was the result of the inoculation of a goat with sheep
blood. Evidently the goat and sheep are so nearly allied and so little difference
exists between the composition of their RBCs that injection of the RBCs of one
induce the formation of a specific lysin for both.
Todd and White's isolysins were effective also against goat RBCs.
S h e e p
and horse apparently were not tested.
When the heated serum of our goat was treated with goat RBCs only the
specific goat isolysin was extracted, leaving the specific sheep heterolysin intact,
but when treated with sheep RBCs both lysins were extracted and the serum no
longer was able to sensitize goat RBCs. Homogenous RBCs therefore, do not
extract a specific lysin, but the heterogenous RBCs for which the lysin is specific
extract both the specific lysin and the isolysin.
In addition to the goat isolysin Goat B had also developed a slight amount of
lysin for horse RBCs, which was comple-mented by guinea-pig serum, but not by
sheep, goat or horse serums.
This goat, as stated before, had been strongly immunised against sheep
RBCs for a period of three years. A less strongly immunised goat developed
no isolysin, and a horse which had been treated with sheep blood for about
n i n e m o n t h s d e v e l o p e d n o h o r s e i s o l y s i n a n d o n l y a p o o r g o a t h e t e r o l y s i n ; s o i t a p p e a r s
that isolysins are not as easily or as quickly formed as heterolysins. The formation
of the horse heterolysin in Goat B indicates a comparatively close relationship
between the horse and the sheep, and it is possible that a prolongation of the
period of immunisation would induce the formation of a greater quantity of the
sensitizer for horse RBCs. Ehrlich several years ago recorded the formation
of isolysins in goats which had been injected with goat blood, and showed that
these isolysins also lysed sheep RBCs. He obtained isolysins of various kinds,
some effective against the RBCs of one group of goats but not of another, others
C-I