114 LOCAL TLSSUE REACTIVITY 



Loweiistcin had noted that the antigenicity of a tetanus toxoid 

 was directly proportional to its antitoxin-conihining capacity. In 

 \ie\v oi the fact that the inenin,o()(()cciis toxoid described by 

 Klein possessed 71.3 per cent ot the antibody-ccjmbinino capac- 

 ity of the mother filtrate, it ^vas expected that the toxoid Avotild 

 still l)e antigenic. 



The aggltitinating titers for Circnip I of the rabbit meningo- 

 cc:)cciis sera produced by subcutaneotis and intravenous injections 

 of Grotip I meningoccjcctis toxoid for a period of fcjiir to five 

 weeks varied from 320 to 1280. Sera obtained from trial bleed- 

 ings of the rabbits prior to immtniization ^vere free of spontane- 

 ous agglutinins for meningococcus. It may be safely assiuned that 

 the meningococctis toxoid studied by Klein retained its antigen- 

 icity. The sera contained no precipitins either for meningococcus 

 acti\'e preparations or for meningococcus toxoid. The sera Avere 

 unable to netUralize meningococcus active principles. Ho^vever, 

 it has been amply emphasized that rabbits do not readily form 

 neutralizing antibodies nor precipitins for meningococcus bac- 

 terial filtrates. 



It is also of interest that there may occur a similar spontaneous 

 formation of meningococcus toxoid. Klein reported that the prep- 

 aration of meningococcus "agar washings" toxic filtrate 1675 was 

 completed by him on June 16, 1931. In the period, July 15 to 17, 

 1931, the titer of reacting units and the antibody-combining- 

 capacity ^vere determined. Antimeningococcus immune horse 

 serimi (with a small amoiuit of auxiliary antifjody, Shwartzman, 

 1931^) ^vas used for the neutralization experiments. In the 

 period Dec. 18 to 23, 1931, these determinations were repeated. 

 It W'as found in the latter experiments that the titer of react- 

 ing imits dropped from 1300 to 150 tmits. Ho^vever, the same 

 amoiuit of serum, which completely neutralized 1 c.c. of a 1:10 

 dilution of meningococcus toxin 1675 in July was necessary for 

 complete neutralization of 1 c.c. of a 1:13.6 dilution of meningo- 

 coccus toxin 1675 in December. Therefore, in December the 

 toxin retained about 1.5 per cent of the July reacting titer. In 

 contrast to this, in December it retained 73.5 per cent of the 

 antibody-combining capacity present in July. 



Thus, Klein's experiments demonstrate clearly that meningo- 

 coccus active principles treated ^vith formalin can be modified 

 similarly to diphtheria toxin. The antigenicity and the antibody- 

 combining capacity are essentially unimpaired. Furthermore, no 



