Blood Groups in Rabbits 283 



Blood Groups in Rabbits 



Agglutination is especially well illustrated by considering the 

 effect of injecting blood from one rabbit into another. As shown 

 by Castle and Keeler, rabbits in general may possess either one, 

 both, or neither of the agglutinogens Hi and H2. If blood is 

 taken from a rabbit that is known to possess the agglutinogen 

 Hi, and if it is injected into a rabbit that does not possess this 

 agglutinogen, the second rabbit after several such injections a 

 few days apart will develop an agglutinin. If blood serum from 

 the recipient rabbit is then added to blood of rabbits that pos- 

 sess the Hi agglutinogen, the blood corpuscles of these other 

 rabbits will then become agglutinated. The Hi agglutinogen 

 acts as an antigen in the body of the rabbit that does not 

 possess it and calls forth the production of this agglutinin. If 

 blood from a rabbit possessing the Hi agglutinogen, however, is 

 injected into a rabbit that already possesses this agglutinogen, 

 it is not foreign, and no Hi agglutinin is produced. Similarly, 

 blood from a rabbit that has the H2 agglutinogen will call forth 

 the production of an Ho agglutinin in rabbits that do not have the 

 H2 agglutinogen. 



The possession of either of these agglutinogens depends upon 

 the possession of certain genes which may be designated H^ and 

 H^ and are allelic to each other. A third allele, h, is also pres- 

 ent at the same locus, but this gene does not produce any ag- 

 glutinogen. Rabbits, then, may be divided into four groups on 

 the basis of these three alleles and the agglutinogens which 

 are merely the phenotypic expression of these genes. The four 

 groups with their genotypes are: 



Group O hh 



Group Hi H^H^ or H^h 



Group H2 H^H^ or H^h 



Group H1H2 H^H^ 



Group O has no agglutinogens and therefore stimulates the for- 

 mation of no agglutinins in any animals. Group Hi causes the 

 production of Hi agglutinin in either group or group H2 indi- 

 viduals, but not in rabbits of either of the other groups. Group 

 H2 blood causes the production of Ho agglutinin only in ani- 

 mals of groups or Hi. Blood from individuals with both 



