title: Extrafollicular plasmablast B cells play a key role in carrying retroviral infection to peripheral organs.
abstract: B cells can either differentiate in germinal centers or in extrafollicular compartments of secondary lymphoid organs. Here we show the migration properties of B cells after differentiation in murine peripheral lymph node infected with mouse mammary tumor virus. Naive B cells become activated, infected, and carry integrated retroviral DNA sequences. After production of a retroviral superantigen, the infected B cells receive cognate T cell help and differentiate along the two main differentiation pathways analogous to classical Ag responses. The extrafollicular differentiation peaks on day 6 of mouse mammary tumor virus infection, and the follicular one becomes detectable after day 10. B cells participating in this immune response carry a retroviral DNA marker that can be detected by using semiquantitative PCR. We determined the migration patterns of B cells having taken part in the T cell-B cell interaction from the draining lymph node to different tissues. Waves of immigration and retention of infected cells in secondary lymphoid organs, mammary gland, salivary gland, skin, lung, and liver were observed correlating with the two peaks of B cell differentiation in the draining lymph node. Other organs revealed immigration of infected cells at later time points. The migration properties were correlated with a strong up-regulation of alpha(4)beta(1) integrin expression. These results show the migration properties of B cells during an immune response and demonstrate that a large proportion of extrafolliculary differentiating plasmablasts can escape local cell death and carry the retroviral infection to peripheral organs.
authors.affiliation: Ludwig Institute for Cancer Research, Lausanne Branch, and Institute of Biochemistry, University of Lausanne, Epalinges, Switzerland.
authors.forename: D
authors.initials: D
authors.lastname: Finke
authors.forename: F
authors.initials: F
authors.lastname: Baribaud
authors.forename: H
authors.initials: H
authors.lastname: Diggelmann
authors.forename: H
authors.initials: H
authors.lastname: Acha-Orbea
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000096:biosynthesis; D016175:B-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism / Q000473:pathology / Q000821:virology; D002454:Cell Differentiation / Q000276:immunology; D002465:Cell Movement / Q000276:immunology; D005260:Female; D006614:Hindlimb; D039441:Integrin alpha4; D039041:Integrin alpha4beta1; D019012:Integrin beta1 / Q000096:biosynthesis; D016023:Integrins / Q000096:biosynthesis; D008198:Lymph Nodes / Q000276:immunology* / Q000473:pathology / Q000821:virology; D008213:Lymphocyte Activation; D008221:Lymphoid Tissue / Q000276:immunology / Q000473:pathology / Q000821:virology; D008325:Mammary Neoplasms, Experimental / Q000276:immunology* / Q000473:pathology / Q000821:virology; D008324:Mammary Tumor Virus, Mouse / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D010950:Plasma Cells / Q000276:immunology* / Q000378:metabolism / Q000473:pathology / Q000821:virology; D016201:Receptors, Lymphocyte Homing / Q000096:biosynthesis; D012192:Retroviridae Infections / Q000276:immunology* / Q000473:pathology; D014412:Tumor Virus Infections / Q000276:immunology* / Q000473:pathology
chemical_list: D015703:Antigens, CD; D039041:Integrin alpha4beta1; D019012:Integrin beta1; D016023:Integrins; D016201:Receptors, Lymphocyte Homing; D039441:Integrin alpha4