Human rheumatoid B-1a (CD5+ B) cells make somatically hypermutated high affinity IgM rheumatoid factors.

ABSTRACT: To analyze the structure and formally ascertain the B-1a cellular origin of IgM rheumatoid factor (RF) autoantibodies, we generated 4 IgM RF mAb-producing cell lines using sorted (surface CD5+) B-1a cells from a patient with active rheumatoid arthritis. The RF mAb111, mAb112, mAb113, and mAb114 were monoreactive and displayed a relatively high affinity for human IgG Fc fragment (Kd, 3.1 x 10(-7) to 6.8 x 10(-7) M). The B-1a origin of the lymphocytes that gave rise to the IgM RF was confirmed by the expression of surface CD5 and specific CD5 mRNA by all mAb-producing cell lines. Analysis of the genes encoding the RF mAb VH and VL regions revealed that members of the VHI and VHIII families were utilized in conjunction with V kappa IIIa, V kappa IIIb, or V lambda I genes. JH3 and JH4 genes we

SUBMITTER: Mantovani L 

PROVIDER: S-EPMC4625548 | biostudies-literature | 1993 Jul

REPOSITORIES: biostudies-literature