Fine-Specificity of the lamba and chi L Chains Associated with Antibodies Directed to alpha(l3) Glucosyls in Dextran

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Abstract
The function of BALB/c [mouse] primary B precursors, responding to dextran (dex) B-1355, and the fine-specificity of the B-1355-binding, .lambda. and .vkappa., monofocal antibody (Ab) generated by the precursors were examined. In splenic fragments from Limulus polyphemus hemocyanin (LPH)-primed, lethally irradiated, euthymic or nu/nu BALB/c mice cultured with thymus-independent (TI) dex B-1355, B-1355-lipopolysaccharide (LPS), B-1355-LPS-LPH, or thymus-dependent (TD) dex B-1355-LPH, the .lambda.1 precursors responded with B-1355-binding Ab substantially equally with respect to precursor frequency, rate of Ab production, and range of fine-specificity, but not with respect to frequency of the IdX and IdI isotypes related to the VH and DH associated with the .lambda.1. The .lambda.2 contributed minimally to the repertoire. The .times. precursors responded with B-1355-binding Ab at a rate nearly equal to the .lambda.1 only under TD stimulus in euthymic fragments. A comparison of the .lambda.1 and .times. Ab fine-specificity, by inhibition of binding with dex differing in epitope contents and configurations, showed marked restriction in the .times. relative to the .lambda.1. Only .apprx. 10% of the relatively more abundant .times. TD response showed fine .alpha.(1 .fwdarw. 3)-specificity similar to that of the .lambda.1. The .lambda.1 fine-specificity diversity resided mainly in the IdI fraction.