152 IMMUNOLOGY 



Opsonins and Bacteriotropins represent normal and immune 

 antibodies, respectively, that unite with specific bacteria and 

 render them more easily engulfed by leucocytes. They are dis- 

 cussed more fully in another chapter. 



Ablastin. — Tliis relatively new antibody was discovered by 

 Taliaferro (1929, 1932). It develops in rats infected with 

 Trypanosoma lewesi and prevents reproduction or cell division of 

 the parasites without apparent injury to them. It differs from 

 other antibodies in that it does not form a demonstrable union 

 with the cells (trypanosomes) which it specifically affects. This 

 type of antibody is not produced as a result of infection with T. 

 hrucei, T. gamhiense, T. rJwdesiense, T. equiperdum, nor has 

 Taliaferro observed it in his studies of the resistance of birds and 

 mammals to certain malarial parasites. 



Antiaggressins. — Pathogenic bacteria vary in their ability to 

 invade the tissues. Marked difference is exhibited by different 

 strains of any one pathogen. Even some strains of C. diphtheriae 

 seem to possess invasive powers. This is suggested by the work of 

 Feierabend and Schubert (1929) and others to which attention has 

 been called recently by Wells (1932). There are immunologists 

 who interpret their experiments as showing that bacterial invasion 

 is prevented by specific antibodies called by them antiaggressins. 

 Their conclusions are based upon the acceptance of Bail's theory 

 of aggressins. The veterinary immunologists have obtained star- 

 tling results by immunizing domestic animals with antigenic ma- 

 terial which they believe contains aggressins. Their work deserves 

 serioiLs consideration by the medical student since their experi- 

 mental studies are both extensive and intensive. Many important 

 papers have appeared in the American Journal of Veterinary 

 Medicine and elsewhere in veterinary literature. 



CoNGLUTiNiNS. — Ehrlich and Sachs (1902) discovered that in- 

 activated bovine serum intensified hemolysis due to amboceptor 

 and complement. Bordet and Gay (1906) and later Bordet and 

 Streng (1909) investigated the phenomenon described by Ehrlich 

 and Sachs and definitely showed that bovine serum contains a 

 colloidal substance named by them conglutinin that unites only 

 with sensitized cells that have adsorbed complement. It intensifies 

 both the agglutination and hemolysis of such cells. They showed 

 that this conglutinin will not unite with either unsensitized or 



