Immunoglobulin Gene Organization and the Mechanism of Repertoire Development

Recombinant DNA technology has made it possible to comparatively examine the immunoglobulin (Ig) gene constitution of numerous species. These studies reveal that many species diverge from the pattern seen in rodents and primates while revealing a number of interesting correlations involving Ig gene organization, B‐cell lymphogenesis and the mechanism of repertoire development; many of these fail to correlate with traditional phylogenetic relationships. These correlates pose new questions regarding repertoire developments, which suggest that considerable diversity exists in the process. These findings also allow new questions to emerge regarding the role of IgD, the size of the B‐cell repertoire, and the role that antigen may or may not play in repertoire development. These issues are discussed with the intention of stimulating experimentation to test a number of speculative hypotheses regarding B‐cell and repertoire development.