CYTOTOXINS 209 



which it unites witli tho .aiiihocrnptor; the other, the toxophoro (or zymophorr, 

 because of its enzynie-lilce action), which attacks the bacterial protoplasm. It 

 may def^enerate and lose its toxoi)hore f^roup while retaining the pow(!r to combine 

 by means of its ha])topiiore )j;i"'Jiil>» thus formiiip; a romplruicntoid. (Complement 

 and aiubocejitor exist side l)y side in the serum, not uniting with one another 

 until the ambocei)tor has become attached to the liactcrial protoplasm. 



It is generally stated that if serum containing complement be so treated as to 

 separate the globulins from the albumin, it is found that the complement has been 

 divided into two parts, one i)resent in each of the protein fractions. The globulin 

 fraction of the complement will unite to am])oceptor which is fixed to cells, and 

 hence is called the mid-pircc of the complement, for it will unite also with the 

 end-piece of the complement contained in the all)umin fraction, and then cytolysis 

 can take jjlace. Without the intervention of the globulin mid-piece the albumin 

 end-piece cannot unite with the amboceptor, while in the ab.sence of end-piece 

 the amboceptor mid-piece complex can cause no cytolysis. Both fractions of the 

 complement are destroyed by heat, but if the mid-piece is bound to the ambo- 

 ceptor it resists heating. The mid-piece corresponds to Ehrlich's haptophore, 

 the end-piece to the toxophore group, and this complex structure is common to 

 both bacteriolytic and hemolytic complement. Bronfenbrenner and Xoguchi,^* 

 however, contend that the supposed cleavage of complement is merely an inactiva- 

 tion by the agencies employed, all the complement being in the albumin fraction 

 in a condition capable of reactivation, not only by globulin but by simple ampho- 

 teric substances, a view which has not been generally accepted. ^- 



Amboceptors are formed, according to Wassermann, and Pfeiffer and Marx, in 

 the spleen and hemopoietic organs, since in immunization they can be demonstrated 

 in these organs before the)^ appear in the circulating blood. The stability of the 

 amboceptors is very considerable: serum prepared in 1895 by PfeifTer against 

 cholera vibrios was found to have lost almost none of its activity after eight years 

 in an ice-box (Friedberger). Heating twenty hours at 60° scarcely injures them, 

 but 70° for one hour destroys them almost completely, and heating the serum to 

 100° destroys all the immune bodies. They are quite resistant to putrefaction, 

 and, like the antitoxins, do not dialj'ze. Strong salt solutions will prevent the 

 union of complement and amboceptor in vitro, and probably to greater or less 

 degree in the animal body, but the union of antigen and amboceptor is not pre- 

 vented by salt.^' Alkalies may prevent the union of amboceptor with the cells, 

 or extract it from the cell to which it has united; and they maj"- also inhibit the 

 union of amboceptor and complement. Amboceptors are not inactivated by 

 shaking, as is complement, but they are destroyed alike by ultraviolet rays, and 

 both resist x-rays.^'* 



According to Pfeiffer and Proskauer,^^ digestion of the globulin precipitate, in 

 which amboceptors are carried down, does not destroy their activity completely 

 even when all the proteins are thus removed. Removal of the nucleo-albumin or 

 nuclein does not remove the amboceptors from the serum. Immune serum kept 

 three months in alcohol yielded an extract with distilled water that was rich in 

 immune bodies, but almost free from protein. Pick, Rhodain, and Fuhrmann 

 found that immune bodies are precipitated entirely in the euglobulin fraction of 

 the serum protein. From these experiments it has been thought bj^ some that 

 the bacteriolytic amboceptor is not itself a protein, although closely associated 

 with the serum globulins.-^ 



CYTOTOXINS 



Just as precipitins can be obtained for proteins derived from other 

 sources than bacterial cells, so also upon immunizing an animal 



-^ Jour. Exp. Med., 1912 (5), 598; good review of literature. 



" See Leschlev, Zeit. Immunitat., 1916 (25), 44. 



" Angerer, Zeit. Immunitiit., 1909 (4), 243. 



" Scaffidi, Biochem. Zeit., 1915 (69), 162. 



" Cent. f. Bakt., 1896 (19), 191. 



^® -\scoli found that the active substance of anthracidal serum, which is not an 

 amboceptor, is contained in the pseudo-globulin fraction of asses' serum, but in 

 goat's serum part is in the euglobulin fraction. (Biochem. Centr., 1906 (5), 458.) 



14 



