  Fundamental to quantitative characterization of the B cell receptor
repertoire is clonal diversity - the number of distinct somatically recombined
receptors present in the repertoire and their relative abundances, defining the
search space available for immune response. This study synthesizes flow
cytometry and immunosequencing to study memory and naive B cells from the
peripheral blood of three adults. A combinatorial experimental design was
employed, constituting a sample abundance probe robust to amplification
stochasticity, a crucial quantitative advance over previous sequencing studies
of diversity. These data are leveraged to interrogate repertoire diversity,
motivating an extension of a canonical diversity model in ecology and corpus
linguistics. Maximum likelihood diversity estimates are provided for memory and
naive B cell repertoires. Both evince domination by rare clones and regimes of
power law scaling in abundance. Memory clones have more disparate repertoire
abundances than naive clones, and most naive clones undergo no proliferation
prior to antigen recognition.
