322 IMMUNOLOGY 



Larjiely through tlie Avork of Lel)lane (1901), Hektoeii (1918), 

 Dale and Hartley (1916), Doerr and Berger (1922), Lewis and 

 Wells (1927) and others it has been shown that blood plasma 

 contains at least five chemically different proteins that are also 

 antigenically different. These plasma proteins are eus'lobnlin, 

 psendo^lobnlin, albnmin, seromncoid and fibrino«'en. Of all these 

 proteiiLs only one, fibrinogen, lacks species specificily. However, 

 even with it there is a quantitative difference that is definite since 

 the maximum precipitate occurs between an antifibrinogen immune 

 serum and the species fibrinogen used to produce it. Goodner 

 (1925) found that beef serum was antigenically different from beef 

 chondromucoid or beef submaxillary mucin. 



Red Cell Proteins. — Hemoglobin present in the red cells is 

 both cliemically and antigenically different from the proteins of 

 the plasma. Even the globulin from the red cells shows antigenic 

 differences from the serum glol>ulin. The red cells also contain 

 lipoids and carbohydrates which form compounds with some of the 

 red cell proteins, giving rise to chemical and immunological dif- 

 ferences. This has been discu.ssed in the cliapter on Blood Group- 

 ing. 



Tissue Proteins. — Downs (1925) has shown that tissue fibrino- 

 gen is species specific antigenically, which is interesting in view 

 of the fact that Hektoen and Welker (1925, 1927) showed that 

 blood fibrinogen does not show species specificity. 



Goodner (1925) found marked antigenic differences between 

 the mucins obtained from beef submaxillary glands and from the 

 hog stomach. He calls attention to the fact that the conjugated 

 proteins are relatively poor antigens and that their antigenic 

 efficiency bears some relationship to the amount of protein pres- 

 ent in the conjugate. This is in harmony with other experimental 

 results which show that with a few exceptions tissue proteins do 

 .show species specificity. 



Organ Specificity. — Pfeiffer (1910) even claimed that antigenic 

 difference could l)e detected between the proteins of the liver, 

 spleen, kidney, etc., but Pearse, Karsner, and Ei.senbrey (1911) 

 failed to confirm Pfeiffer 's claims. Later Fleischer (1920, 1921) 

 seem.s to have demonstrated some slight difference. 



Lens and Testicular Proteins Shonv Nonspecies Specificity. — 

 Of the tissue proteins lacking species specificity, those of the 



