Comparative Studies on Monotypic IgMλ and IgGκ from an Individual Patient

[摘要] Amino terminal sequence analyses were performed on the H and L chains of the idiotypically related IgMλ and IgGκ paraproteins isolated from the sera of a patient, Br. The N-terminal 41 residues of the Br κ-chain belonged to the VKIII subgroup, and L chains derived from BrIgMλ revealed a blocked N-terminus characteristic of λ-chains.Comparative sequence analysis of the Br µ- and γ-chains indicated that, although both possessed an unblocked N-terminal glutamic acid, the respective VH regions belonged to separate subgroups. The N-terminal 27 residues of the Br µ-chain reflected a typical VHIII subgroup sequence. The Br γ-chain sequence demonstrated a VHI pattern with an unblocked N-terminus. These structural data stand ir contrast to previously reported serologic evidence, which indicated that the BrIgMλ and BrIgGκ proteins possessed highly similar VH-associated idiotypic determinants. Final interpretation of these findings of similar VH idiotypic determinants expressed by H chains belonging to separate VH subgroups must await complete sequence analysis of the hypervariable segments of the Br γ- and µ-chains.

[学科分类] 生物科学（综合）