Prado-Zamora, Maria CarmenRodriguez-Garcia, MercedesCortegano, IsabelRuiz, CarolinaAlia, MarioAndres, Belen deGaspar, Maria Luisa2020-05-182020-05-182014J Innate Immun. 2014;6(4):499-514.1662-811Xhttp://hdl.handle.net/20.500.12105/10149The diversity in antibody repertoire relies on different B cell populations working efficiently to fulfil distinct specific functions. We recently described an innate-like CD19(+)CD45R(-/lo) (19(+)45R(lo)) cell population in postnatal unstimulated adult mice, a heterogeneous population containing cells expressing immunoglobulin M (IgM) and others behaving as differentiated mature B lymphocytes (intracytoplasmic IgG1, AID(+), Blimp-1(+)RAG2(-)). In the present study, we characterized the Ig repertoire expressed by splenic 19(+)45R(lo) cells, assuming that they would bear a restricted repertoire biased for germline rearrangements and low mutation rates similar to other innate-like cells. Sequences from 19(+)45R(lo) cells displayed a variety of V, D and J regions, and the analysis of the CDR-H3 region revealed an intermediate overall CDR-H3 length and moderate hydrophobicity. Both IgM and switched sequences of PD15 19(+)45R(lo) cells had shorter CDR-H3 region and fewer non-template N nucleotides than adult sequences, as expected for profiles that correspond to an immature phenotype. Regarding the mutation rate in the VH regions, IgG1 sequences already carried a high rate of replacement mutations at PD15, which increased further in the sequences obtained from adult mice. Moreover, statistical models suggest that a proportion of the switched sequences in adult 19(+)45R(lo) cells had experienced antigen selection, unlike other innate-like B cell compartments.engAMhttp://creativecommons.org/licenses/by-nc-sa/4.0/AnimalsAnimals, NewbornAntibody DiversityAntigens, CD19B-Lymphocyte SubsetsB-LymphocytesCell DifferentiationCells, CulturedImmune SystemImmunity, InnateImmunoglobulin Class SwitchingImmunoglobulinsImmunologic MemoryLeukocyte Common AntigensMiceMice, Inbred BALB CV(D)J RecombinationAtribución-NoComercial-CompartirIgual 4.0 Internacional2460360264499-51410.1159/0003582371662-8128Journal of innate immunityopen access