jerne's theory 



whether the multiplicity of antibody reactivities in gamma 

 globulin molecules is a random character due to a simple 

 indeterminacy of pattern in the molecules produced or 

 whether there are clones of cells which produce pattern a, 

 others pattern b, and so on for the thousands of patterns 

 required. This second possibility would naturally also 

 demand a corresponding range of coding for pattern in the 

 nucleic acids of the cells forming the clones in question. 

 Jerne appears to favour the first alternative and to assume 

 that when a (partially denatured) globulin molecule which 

 happens to have pattern x is brought to any one of the anti- 

 body-producing cells this cell is stimulated to produce 

 globulin of definitive pattern corresponding precisely to the 

 random pattern of the 'natural' antibody molecule. This 

 appears to be out of line with any of the current ideas on 

 protein synthesis and is one of the main points which led to 

 the development of a ' clonal selection ' theory. 



5. The clonal selection theory 



The great contribution of Jerne's theory was that it drew 

 attention to the theoretical possibility that the recognition 

 of self from not-self could be achieved in another fashion than 

 by the recognition of 'self-markers'. As Talmage (1957) 

 points out, Ehrlich's side-chain theory was in many ways 

 the logical equivalent of Jerne's concept. The side-chain 

 theory was quietly shelved as evidence accumulated of the 

 vast variety of antibodies that could be produced, some 

 against non-biological determinants such as arsanilic acid. 

 It seemed, and to most immunologists still seems, inconceivable 

 that all types of antibody could be pre-existent in the normal 

 complement of gamma globulin molecules. Nevertheless, if 

 Jerne is correct that a comprehensive range of molecules 

 corresponding to all organic patterns other than those of 

 body components is present in the gamma globulin popula- 

 tion, this would be an effective and much more elegant way 

 of accounting for the differentiation of self from not-self. 



53 



