H. Kiyoi et al., COMPARABLE PROFILES OF THE IMMUNOGLOBULIN HEAVY-CHAIN COMPLEMENTARITY-DETERMINING REGION (CDR)-3 IN CD5(-) HUMAN CORD-BLOOD B-LYMPHOCYTES()AND CD5(), Immunology, 85(2), 1995, pp. 236-240
It has been suggested that CD5(+) B cells are closely related to the p
athogenesis of autoimmune disease or chronic lymphocytic leukaemia, wh
ereas the origin and physiological role of CD5(+) B cells remain contr
oversial. To study the molecular differences between CD5(+) and CD5(-)
B cells in terms of immunoglobulin gene structure, we sorted both sub
sets from new-born cord blood and analysed the complementarity determi
ning region (CDR)-3 profiles of the immunoglobulin heavy chain (IgH) g
ene. The CDR-3 sequences from both CD5(+) and CD5(-) B cells represent
ed the same incidence and length of N-region, and the same usage of D
and J(H) segments. When translated into amino acids, 24 of 32 clones (
75%) and 25 of 37 clones (65 . 8%) from their respective subset were p
roductive, and the composition of the deduced amino acids were similar
between both subsets. These data suggest that CD5(+) B cells are not
a distinct lineage presenting a biased immunoglobulin repertoire in B
cells.