37
D. 20 per cent. suspension rabbit RBCs sensitized
1 in 20 parts heated sheep serum
•••
...
0.25
Partial
50 per cent.
Salt ...
...
•••
•••
•••
...
1.5
Fresh guinea-pig serum ......
...
..
0.25
E. Desensitized serum from D
•••
•••
...
1 . 0
Partial
50 per cent.
Fresh guinea-pig serum
•••
•..
0. 25
Salt ...
•••
..
...
...
...
0 . 7
Rabbit RBCs
...
•••
...
..•
0.05
If no other auxilytic or antilytic agencies are at work a just representation
of the amount of lysis occurring should be made by the following equation :—
(D-B)+(E-B) = (A-B) i.e., the effect of the total amboceptor which is present
in D and E should equal the effect of a similar quantity of amboceptor in C, the
complement being in each case equal. Allowance is made by subtracting the
effect of the fresh guinea-pig serum itself on the RBCs in each instance. A possi-
ble error might exist in the effect of fresh guinea-pig serum on heterogenously
sensitized RBCs not being the same as on unsensitized RBCs, but experiments made
to ascertain the effect of two amboceptors acting on the same RBCs lead us to
believe that no error would be introduced thus.
Fitting the figures indicating the percentage of lysis to the formula we get
—
(D-B)+(E-B)=(A-B).
(50-20)+(50-20) = (80-20).
30+30=6o.
showing that the presence of heated sheep serum in the mixture has no auxi-
lytic effect. If it had, the second term of the equation would be larger than the
first.
As the quantity of complement in the series decreased, there was less lysis in
rows C and E ; and when the total percentages of lysis of the whole experiment
were compiled we got—
(230-60) + (103-60)=(205-60).
213=145.
This discrepancy is due to the antilytic action of the heated serum present in
rows C and E which is absent from row D. 3.75 per cent. fresh guinea-pig serum
in the mixture can produce 25 per cent. of lysis of sensitized rabbit RBCs, whereas
in the presence of 1 cc of heated serum a similar quantity gives no lysis.
We have then to conclude that a heated serum in a mixture, when complement
is in excess, gives more lysis than is obtained with RBCs previously sensitized in
an equivalent quantity of heated serum, i.e., the RBCs do not attach all the available
amboceptor when put in a heated normal heterogenous serum to be sensitized.
When, however, complement is not in excess, more lysis is obtained from sensitized
RBCs, since the presence of a large quantity of heated serum in a hœmolytic system
has an antilytic effect. In the particular instance now under discussion the lessened
degree of lysis is probably in some measure to be accounted for by deviation of
complement owing to excess of amboceptor in the heated serum added.
1 1 . A n a p h y l a x i s .
Sheep S received an injection of 7 cc washed goat M RBCs intravenously. 18
days later its serum gave no lysis with goat M RBCs, but with the aid of guinea-pig
complement complete lysis was obtained. Evidently a certain amount of amboceptor
had been formed but not sufficient to enable the amount of complement available
in the sheep's own serum to cause lysis.
On the same day 15 per cent. of this sheep's serum in a total of 2 cc fluid com-
pletely lysed 0.05 cc rabbit RBCs. The sheep then received a further intravenous
injection of 17 cc washed goat M RBCs andits serum was tested 22, 45 and 180
minutes later against rabbit RBCs to see if an appreciable quantity of complement