Differential Expression of Vn Gene Families in Per/pheral B Cell Repertoires of Newborn or Adult Immunoglobulin H Chain Congenic Mice

The pattern of V. gene family expression in the primary B cell repertoire of the mouse is strain dependent. In C57B1/6 mice, the V. J558 family is expressed by more than 45% of the cells, while the expression of V. 7183, V. Q52, and V. 36-60 families together does not exceed 20%. In BALB/c mice, relative expression of V. J558 is lower than 35%, while the sum of the other three families reaches 25%. To assess which genetic loci control strain-specific V. gene family expression, we studied V. gene family usage in splenic B cell repertoires of different congenic strains of mice. Changes in major histocompatibility complex or immunoglobulin (Ig) K light chain genes did not modify V. gene family expression in adult mice. Differences at the IgH locus, however, modified V. gene family usage. In 1-d-old mice, the strain-specific V. gene family expression pattern is determined by the IgH haplotype. In adult mice, the V. gene family expression pattern of resting B cells is independent of the IgH locus and follows the genetic background of the congenic strain, while it is determined by the IgH haplotype among Ig-secreting spleen cells. In FI(B6 x BALB/c) mice, each of the two spleen B cell populations, sorted on the basis of # heavy chain allotype expression, shows an independent V. gene family expression pattern, determined by the IgH locus. The implications of these results in the control of V. gene family expression, and in the selection of peripheral B cell repertoires are discussed.