740 PASSIVE IMMUNIZATION SERUM THERAPY 



none or but very little preservative is required. 1 Efforts are being made at present to 

 discover an efficient volatile antiseptic that may be driven off by warming the serum 

 at body temperature. 



Method of Kolle. Kolle prepares antimeningococcus serum by immunizing 

 horses with heated and then with living cultures or with bacterial extracts. All 

 injections are given intravenously. 



(a) With Cultures. The first dose equals half a culture removed with normal 

 salt solution from a test-tube of slanted agar after twenty-four hours' incubation, 

 and heated at 60 C. for half an hour. A week later the dose equals that of a whole 

 slant. The dose is increased each week by one slant until 10 are given. The eleventh 

 dose equals one agar slant of living culture, and each week the dose is increased 

 until the growths from 10 slants are given at one time. Fourteen days after the last 

 injection the horses are bled and the serum is tested. 



(6) With Bacterial Extracts. Horses are first injected with two doses of heated 

 cultures, as just described. The third dose consists of 0.1 c.c. of bacterial extract. 

 Every two weeks the dose is increased by 1 c.c. of extract until 5 c.c. are given at one 

 tune. 



Standardization of Antimeningococcus Serum. An accurate method of stand- 

 ardizing antimeningococcus serum has not as yet been devised. In the selection of a 

 serum physicians must, therefore, be guided by the reputation of the manufacturers. 



An antimeningococcic serum of high antibody content has antitoxic, bacterio- 

 tropic, and bactericidal properties. Kraus and Dorr consider that the chief function 

 of the serum is antitoxic; Flexner and Jobling, Neufeld, Jochmann, and Wassermann 

 believe that its bacteriotropic properties are its most important qualities. 



The following methods for testing an immune serum are in use or have been 

 advocated; none of them is, however, sufficiently reliable to serve as a definite 

 measure of antibody content or of curative value; two of them, the bacteriotropic and 

 the complement-fixation test, are most widely used in laboratories for the purpose of estimat- 

 ing the antibody content of a serum. 



1. Bacteriotropic Titration. While the antimeningitic serum was being prepared 

 at the Rockefeller Institute, Jobling 2 used the opsonic test in standardization as the 

 method of choice, on account of the part taken by specific opsonins in promoting 

 recovery from meningococcus infections. As a definite and suitable standard of 

 strength Jobling has suggested that a serum be accepted as satisfactory when it shows 

 unmistakable phagocytic activity in dilutions up to 1 : 5000. The method of Neufeld 

 is used, as described on page 200. 



2. Complement- fixation Tests. The advantages of these tests are that the same 

 polyvalent antigen may be used as is employed for purposes of immunization; the 

 technic is simple, and the reactions are usually sharp and definite. According to 

 Sophian, in a series of comparisons with opsonic and complement-fixation tests the 

 results corresponded in every instance, a high opsonic content being accompanied by 

 a high complement-fixation reading. The latter indicates, at least, that the horse has 

 responded to immunization and that curative antibodies probably are present. Labor- 

 atories usually adopt their own standards in preparing antimeningococcic serum. In 

 the complement-fixation test Kolle requires complete inhibition of hemolysis with 

 0.1 c.c. of serum. 



The technic of these tests is given on page 491. 



3. Agglutination Tests. These tests are readily conducted with the polyvalent 

 antigen used in immunization, a macroscopic technic, as that described on page 284, 



1 Hall, W.: Bull. No. 91, Hyg. Lab., U. S. P. H. S., 1914. 



2 Jour. Exper. Med., 1909, xi, 6, 4. 



