The immunoglobulin heavy chain class switch

Conclusions While much has been learned concerning the molecular structural basis for the heavy chain class switch, many questions relating to the regulation of the switch remain unanswered, or at least controversial. Identification of the enzyme system which mediates the class switch, as well as other regulatory, possibly X-linked, genes should provide the necessary key to our understanding of this unique process.AbbreviationsB cell lymphocyte derived from the bone marrow in adult mammals or the bursa of Fabricius in chickens - bp base pair - C immunoglobulin constant region - CDR complementarity-determining region of the immunoglobulin variable region - D diversity gene segment of the immunoglobulin heavy chain variable region gene - H immunoglobulin heavy chain - Ig immunoglobulin - J joining region gene segment of the immunoglobulin variable region gene - kb kilobase - L immunoglobulin light chain - LPS lipopolysaccharide - Pyr pyrimidine - S-, s-site, s-region switch rearrangement site - SCE sister chromatid exchange - sIg surface immunoglobulin - T cell lymphocyte derived from the thymus - USCE unequal sister chromatid exchange - V immunoglobulin variable region