33
9. Various Factors which influence Specific Lysis.
For practical purposes it is desirable to be aware of the effect of dilution of
complement and of the lessening of lysis that may be expected on this account. Series
were therefore put up with each tube containing equal quantities of previously
sensitized RBCs and of complement, but increasing volumes of salt solution.
Chart No. 5 shows graphically the result of the experiments. When the con-
centration of complement was above II per c ent. complete lysis occurred ; when the .
concentration was 8 . 30 per cent. there was 75 per cent. of lysis, when 5 . 75 per cent.
there was 50 per cent; of lysis ; and when only 3 . 9 per cent. there was practically no
lysis within one and a half hours, the time limit of the experiment. Within limits
it may be seated that the degree of lysis in a given time, the quantity of complement
remaining constant, is inversely proportional, to the concentration of that comple-
ment in the mixture.
Chart No. 6 shows that, under the particular conditions of an experiment,.
complete lysis occurred with dilutions of complement below 10 per cent. and
" trace " lysis with a dilution of 30 per cent.
Again for practical purposes it is desirable to be certain whether different
periods of incubation within the ordinary experimental limits have an influence to,
be reckoned with in dealing with small quantities of complement, i.e., wheth.er a.
quantity of complement which does not give an appreciable deree of lysis, say, in
30′ would do so after 120′ incubation, and whether 3 hours' incubation would make
much difference. In the experiment put up (Chart No. 7) the complement used
was weak, so that complete lysis was only reached
With 33 per cent. concentration in 72 minutes.
,, 29
, ,
,,
90
„
„
2 6
, ,
,,
120
,,
„
23
,,
,,
138
„
, , I 9
, ,
, ,
162
„
,,
1 6
,,
,,
1 8 0
„
Approximately, it may be stated that the degree of lysis for any dose of
complement is inversely proportional to the time of incubation. This, naturally,
only applies to mixtures containing the dilutions of complement which have been
previously warmed to 38°C. before the addition of sensitized RBCs. Then the
complement is in a position to begin to act at once. When sensitization has not
been previously performed much more time elapses before lysis begins, though in
the end the results are much the same. The experiment indicates on the one
hand that, given sufficient time, almost a trace of complement will effect complete
lysis provided that sensitization is strong, and on the other that, if sensitization is.
strong and complement is in great excess, complete lysis will occur with great
rapidity, though scarcely instantaneously. The meaning to be attached to such
terms as " strong sensitization " is discussed in another section.
1o. On the Effect of the Presence of a Heated Serum on a
Hemolytic System.
It has been noted by several observers that the presence of certain quantities
of heated serum tends to inhibit lysis of erythrocytes by either normal or artificial
lytic serums.
Ehrlich attributes this effect to the formation of complementoids from the
complement by the action of heat, and suggests that they unite with the receptors
of sensitized erythrocytes and so block the union of the complement.
With the idea of finding out whether this effect might not be due to purely
physical influences, such as viscosity, we made a considerable number . of
experiments.
Chart No. 8 exhibits in tabular form the amount of inhibition that was
observed, using for the hæmolytic system sheep erythrocytes, sensitized in