Bence Jones proteins and light chains of immunoglobulins. XIV. Conformational dependency and molecular localization of the kappa (kappa) and lambda (lambda) antigenic determinants.

The region on the light chain molecule responsible for expression of the kappa and lambda antigenic determinants was determined by comparative immunochemical analyses of intact Bence Jones proteins and naturally occurring or enzymatically derived fragments of Bence Jones proteins that lacked extensive portions of the V region or part of the C region. The reactivity of these fragments with numerous antisera having specificity for light-chain antigenic determinants indicated the essentiality of the intact light polypeptide chain for expression of the kappa and lambda antigenic determinants. The conformational dependency of the kappa and lambda antigenic determinants was also evidenced by denaturation-renaturation studies on kappa and lambda chains. The V domain, C domain, and interdomain 'switch' region contribute to the expression of kappa and lambda antigenicity and to certain isotypic and allotypic specificities.