Antibody responses to lambda 1J558 and lambda 2315 light chains. Specificity and genetic regulation.

Specificity of BALB/c antibody responses to lambda chains of isologous myeloma proteins 315 and J558 was explored by enzyme-linked immunosorbent assay. lambda-chain binding antibodies were not detected when immunizing with assembled (H + L) myeloma proteins. However, relatively high titred IgG antibodies were elicited by free lambda 2(315) immunization. Antibodies were directed to 'hidden' determinants since binding was abrogated upon H + L assembly of chains. At least a portion of antibodies bound antigenic determinants in the variable region and cross-reacted with lambda 1 land lambda 3 chains. Free lambda 1J558 immunization induced low-titred, predominantly IgM antibodies that also only reacted with 'hidden' determinants. These determinants were most probably located in the constant (C) region and no cross-reaction to lambda 2 or lambda 3 was observed. An artefact of technical importance was noted: myeloma proteins exposed 'hidden' determinants on their lambda chains when coated directly to polystyrene walls. This artefactual exposition was lost when anti C-region antibody spacer molecules were inserted between the wall and the myeloma proteins. Antibody and T helper cell (Th) responses to free lambda 2(315) covaried significantly in various strains while antibody and Th responses to free lambda 1J558 did not. In some strains, weak antibody responses were detected without detectable Th.