758 PASSIVE IMMUNIZATION SERUM THERAPY 



culture is immediately made from the blood and also one from a portion of sputum 

 coughed up from the lung, or, when this is not obtainable, a culture is made directly 

 from the lung by the insertion of a needle. This procedure seems to be without 

 danger. When there are large numbers of organisms in the sputum, a culture may 

 be obtained most rapidly by injecting the washed sputum into the abdominal cavity of 

 a mouse. After four or five hours the peritoneal cavity may be washed out with salt 

 solution and the cells thrown down in the centrifuge; a suspension of the organisms 

 is thus obtained. In whatever way the culture is obtained, the agglutination test 

 is at once applied. If the organism fails to agglutinate with either Serum 1 or Serum 

 2, it is, of course, useless to undertake serum treatment. If, however, one of the 

 serums agglutinates the organism, treatment may be commenced at once with the 

 appropriate one." 



Preparation of Antipneumococcus Serum. Horses are immunized with dead 

 and then with virulent living cultures. In view of the fact that the serum should 

 possess some antitoxic value, it is desirable that the animals be immunized also with 

 autolysates. The whole process may be conducted after the method described for 

 the production of antimeningococcus serum. 



In the Rockefeller Institute different horses are immunized with strains belong- 

 ing to Groups 1 and 2. It would appear possible to produce a potent polyvalent 

 serum, and this is very much to be desired, especially if further studies continue to 

 show that 65 per cent, of infections are caused by organisms belonging to these two 

 groups. 



Kolle, by immunizing horses with cultures secured from pneumonia patients, 

 produces an antipneumococcic serum. These cultures are grown in broth for forty- 

 eight hours, heated to 60 C., and 5 c.c. injected intravenously into a horse. The 

 dose is increased each week until 120 c.c. are given at one time. Then 5 c.c. of living 

 culture is injected, and the doses increased in a similar manner until 120 c.c. are given 

 at one time. About six months are consumed in the process of immunization, and 

 two weeks after the last injection has been given the serum is tested. 



Standardization of Antipneumococcus Serum. As previously mentioned, there 

 is at present no accurate method for standardizing an antibacterial serum. It 

 is possible, however, to obtain some measure of its protective and curative power by 

 employing various tests . 



1. Protective Value. The lethal dose of a living pneumococcus culture for mice 

 is determined, and from 10 to 100 times this amount of culture is mixed with decreas- 

 ing doses of immune serum and the mixtures injected subcutaneously or intraperitone- 

 ally into a series of mice in order to determine the dose of serum that will protect. 

 Dochez has found that when these mixtures are injected at once and in the same place, 

 the serum will obey the law of multiple proportions up to a certain limit. 



Merck's antipneumococcus serum is so standardized that 0.01 c.c. injected 

 subcutaneously protects a mouse inoculated intraperitoneally twenty-four hours 

 later with from 10 to 100 times the lethal dose of a living virulent culture. This is 

 known as a normal serum, 1 c.c. containing an immunity unit (I. U.). The serum is 

 marketed in vials containing from 20 to 40 c.c. Kolle regards as satisfactory a serum 

 that, in doses of 0.001 c.c. and less, will protect mice. 



2. Bacteriotropic Value. Neufeld lays considerable stress upon this point. The 

 technic of this titration has been described elsewhere. 



3. Complement-fixation and Agglutination Tests. While these tests are fre- 

 quently sharply cut, and while they serve as a measure for record in the laboratory, 

 they do not necessarily indicate the therapeutic value of the serum. 



