Vλ-light chain genes reconstitute immune responses to defined carbohydrate antigens or haptens by utilizing different VH genes

The contribution of the λ-light chain to the development of peripheral B cell repertoire and generation of specific antibodies to haptens and polysaccharide antigens was studied in genetically manipulated kappa-deficient and λ₂-transgenic mice. The results clearly demonstrate a non-stoichiometric V_H gene family expression in the absence of k-light chain and suggest a non-stochastic pairing between V_H and V_λ genes, expressed in the peripheral B cell repertoire. A shift in V_H gene utilization in the case of Vl_λ⁺ antibodies was evident in response to β2–6 fructosan and TNP hapten. These observations demonstrate the availability of compensatory mechanisms in the absence of V_K genes and are consistent with the hypothesis that V_H gene family expression is controlled by genetic factors from inside the V_H locus. Furthermore, genetic factors from outside the V_H locus, namely restricted available light chain diversity, may lead to a shift in V_H gene utilization in the peripheral B cell repertoire.