IMMUNOLOGICAL STUDIES OF 

 EARLY DEVELOPMENT 



ALBERT TYLER: kerckhoff laboratories of biology, 



CALIFORNIA INSTITUTE OF TECHNOLOGY, 

 PASADENA, CALIFORNIA* 



During recent years there has been mcreasmg interest in the 

 apphcation of immunological methods and concepts to the anal- 

 ysis of problems of the formation and early development of the 

 embryo. The subject was reviewed a short while ago by the au- 

 thor (Tyler, 1955b). In this paper some of the newer develop- 

 ments in this field are presented along with pertinent background 

 of earlier work. The material to be considered concerns the origin 

 of adult antigens and of antibody-forming capacity, effects of 

 antibodies on development, and a concept of natural auto-anti- 

 bodies. A brief account is also included of some current experi- 

 ments of the author on inhibition of cleavage by antisera. 



Immunologically produced antibodies possess the capacity to 

 react selectively with the specific substances (antigens) em- 

 ployed to induce their formation and with substances possessing 

 certain related stmctural features. The classical experiments of 

 Landsteiner (1917-1946) showed that determinants of antigenic 

 specificity may be represented by relatively small chemical groups 

 on a large complex molecule rather than by the structure of the 

 molecule as a whole. This is illustrated in experiments in which 

 a small molecular substance of known structure, such as arsanilic 

 acid, is conjugated with proteins, such as those of horse serum. 

 When this antigen is injected into a rabbit the antiserum that is 



* Preparation of this article and original investigations of the author 

 reported herein were supported by a research grant (No. C-2302) from 

 the National Cancer Institute, of the National Institutes of Health, Public 

 Health Service. 



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