92 



INTRODUCTION TO IMMUNOCHEMICAL SPECIFICITY 



red cells by human or rabbit anti-Lewis sera was not detectably in- 

 hibited by L-fucose or by any other components of the blood group 

 substances. Certain oligosaccharides containing fucose did inhibit, 

 however, which showed that a-L-fucopyranosyl groupings were in- 

 volved in Le' specificity (Morgan and Watkins, 1959). From a 

 study of the inhibitory activity of various oligosaccharides, mostly 

 isolated by Kuhn and his colleagues from human milk (Kuhn, 1957), 

 Morgan and Watkins suggest that the terminal portion of the specific 

 part of the Le' substance is a trisaccharide of the structure shown 

 in Fig. 7-8. 



Action of Genes 

 The way in which the ABO, secretor, and Lewis genes cooperate 

 to produce the various blood group substances found in the body 

 fluids of persons of different genotypes is still to be worked out. 

 Watkins and Morgan (1959) have proposed the following scheme 

 as a first approximation. Three independent gene systems, L' and V, 

 S' and s', and the ABO genes, are supposedly involved. In various 



TABLE 7-2 

 Possible Genetic Pathways for the Production of Blood Group Substances. I' 



Watkins and Morgan, 1959. 



