9,L)6 LOCAL TISSUE REACTIVITY 



pared by iiiinuini/ation with cholera "a^ar washings" (ihrates 

 iieutrali/ed the hoiiiolooous liltrate in dihitioii 1:50. Tlie human 

 conxaleseent serum did not neutralize the skin-j)rej)aratory etteet 

 of this filtrate. Both sera, however, (ontained hi^h jjotency ag- 

 glutinins. These authors eoncluded that the neiitrali/ino power 

 of the antiserum coincided \vith the agglutinating po^ver only 

 incompletely. 



Similarly, it ^vas frequently observed by me that the neu- 

 tralizing titers of anti-typhoid and anti-coli sera only rarely paral- 

 leled the aggltitination titers. There ^vas also observed a discrep- 

 ancy bet^veen the precipitation and neutralizing titers. Further 

 studies on the ffocciilation reactions are necessary before a defi- 

 nite statement can be made. It is also of significance in this con- 

 nection that the agglutinating and antitoxic titers of diphtheria 

 antitoxin do not run parallel (Martin, 190^^) . 



Since the above experiments sho\vecl that the immune anti- 

 meningococcus sera employed therapeutically were of low neu- 

 tralizing potency, inrmunization of goats and horses \vas begun 

 in my laboratories and also jointly ^vith Dr. William H. Park, 

 in the New York City Board of Health, by means of combined sub- 

 ciUaneous injections of the active priirciples and intravenous in- 

 jections of heat-killed vaccines. By this time, there was developed 

 a standardized method for titration of neutralizing potency of 

 anti-typhoid sera. This method ^vas then adopted for the work 

 with meningococcus sera (pp. 95, 97) . Accordingly, the foUo^ving 

 was found: 



There Avas obtained consistent neutralization of meningococcus 

 reacting factors by means of potent immtuie sera. The neutraliz- 

 ing potency could be fairly accurately derived by determining 

 the largest amount of reacting factors completely neutralized (i.e., 

 in all animals tested) by a given amount of serimi (0.25 c.c. or 

 1 c.c.) .^ 



It was again observed that among the additional series of anti- 

 meningococcus therapeiuic sera only a few sera Avere capable of 

 neiUralizing more than 25 to 40 reacting units of Type I and 

 Type III meningococcus active principles. In contrast, a goat 

 serinn prepared by immtmization with the active principles of 

 meningococcus Group I "vvas able to neiUralize consistently about 



^ 111 some of the neutralization tests the auxiliary antibody descriljed in Chapter 

 IV was used for convenience. With potent sera clear-cut neutralizations mav he 

 obtained, however, without the aid of this heterologous antibody. 



