title: Diversification of the primary antibody repertoire begins during early follicle development in the rabbit appendix.
abstract: Rabbits generate a diversified primary antibody repertoire by somatically mutating, in gut-associated lymphoid tissue (GALT), an initial repertoire that is limited by preferential rearrangement of the 3'-most IGVH gene segment. To determine when repertoire diversification begins in GALT, we performed in situ hybridization on neonatal rabbit appendix sections with an activation-induced cytidine deaminase (AID) riboprobe, because AID is required for the mutational processes that diversify the primary antibody repertoire. We first detected AID mRNA expression around 1 week of age, in the basal region of developing follicles. By PCR-amplifying V-D-J genes from AID mRNA(+) B cells isolated by laser capture microdissection, we found evidence of somatic hypermutation, and one likely instance of somatic gene conversion. Our results suggest that V-(D)-J gene diversification begins during early postnatal appendix development, in B cells stimulated to enter a proliferative program by signals derived from select intestinal commensals.
authors.affiliation: Department of Microbiology & Immunology, Loyola University Chicago, Maywood, IL 60153, USA.
authors.forename: Shi-Kang
authors.initials: SK
authors.lastname: Zhai
authors.forename: Dennis K
authors.initials: DK
authors.lastname: Lanning
mesh_terms: D000818:Animals; D000916:Antibody Diversity / Q000235:genetics / Q000276:immunology*; D001065:Appendix / Q000276:immunology* / Q000378:metabolism; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism; D003564:Cytidine Deaminase / Q000235:genetics / Q000378:metabolism; D008221:Lymphoid Tissue / Q000276:immunology / Q000378:metabolism; D011817:Rabbits; D060152:V(D)J Recombination
chemical_list: D003564:Cytidine Deaminase