The frequency of para-azophenylarsonate and dimethylaminonapthalene-sulfonyl-specific B cells in neonatal and adult BALB/c mice.

The limiting cell dilution splenic focus technique has been used to determine the frequency of p-azophenylarsonate (Ars) and 5-dimethylaminonaphthalene-sulfonyl (Dansyl)-specific B cells in neonatal and adult mice. The adult frequencies for Ars and Dansyl in conventionally reared BALB/c mice are 1.5 +/- 0.3/10(5) B cells and 9.4 +/- 3.3/10(5) Bcells, respectively. Dansyl-specific precursor cells are present in high frequencies at birth and reach adult precursor frequency levels during the first week of life. This finding mirrors the ontogenetic development previously described fro dinitrophenyl (DNP) and trinitrophenyl (TNP), but contrasts with the results obtained fro fluorescein (FL) and phosphorylcholine (PC), for which precursors arise later in development. On the other hand, the kinetics of appearance of B cells specific for Ars is unique in that the precursor frequency appears to decrease during the first week of life. The data presented remain consistent with a highly ordered, rigorously predetermined acquisition of the specificity repertoire during ontogeny. By increasing the flexibility of the splenic focus technique to allow analysis of other, chemically diverse haptens, results have been obtained that confirm and extend observations made with DNP, TNP, FL, and PC.