title: Activation of B1a cells in peritoneal cavity by T cell-independent antigen expressed on polymeric micelle.
abstract: A polymeric micelle (Lactosome) composed of amphiphilic polydepsipeptide, poly(sarcosine)-block-poly(L-lactic acid), was reported as a T cell-independent antigen. We show here that Lactosome-responsive B cells are predominantly found in the peritoneal cavity (PerC). After immunization of mice with Lactosome, antibody-secreting cells (ASCs) are found only in spleen and bone marrow (BM), but not in PerC. The enzyme-linked immunospot assay shows that the dominant ASCs are plasmablasts in spleen. 5-Bromo-2'-deoxyuridine (BrdU) assay reveals that Lactosome-responsive peritoneal B1a cells proliferate by the stimulation of Lactosome and the majority of them stay there. These data indicate that the primary site for Lactosome to interact with B cells is in PerC, and some of activated B cells migrate into spleen or BM and differentiate into plasmablast there. As expected, when the B1a cells in PerC are collected from the Lactosome-immunized mice and are transplanted into recombination activating gene 2 (RAG2)(-/-) mice, the anti-Lactosome immunoglobulin M (IgM) production is observed in the recipient mice. It is therefore considered that the peritoneal B1a cells stimulated by Lactosome are the source of the sustained plasmablasts in spleen.
authors.affiliation: Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan.
authors.forename: Cheol Joo
authors.initials: CJ
authors.lastname: Kim
authors.forename: Eri
authors.initials: E
authors.lastname: Hara
authors.forename: Akira
authors.initials: A
authors.lastname: Shimizu
authors.forename: Manabu
authors.initials: M
authors.lastname: Sugai
authors.forename: Shunsaku
authors.initials: S
authors.lastname: Kimura
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008823:Micelles; D010529:Peritoneal Cavity / Q000166:cytology / Q000502:physiology*; D011108:Polymers / Q000378:metabolism*; D013601:T-Lymphocytes / Q000378:metabolism*; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7 / Q000378:metabolism*
chemical_list: D008823:Micelles; D011108:Polymers; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7
keywords: clearance; immune response; immunology; micelle; nanoparticles; polymeric drug carrier