A. Methods-mice and . Balb, PHIL (C57BL/6 background) and C57BL/6 mice from Mayo Clinic Arizona, US. For primary immunization, mice were immunized i.p. with 100µg of alum-precipitated or CFA-emulsified phOx coupled to CSA. After 6-8 weeks animals were boosted i.v. with 100µg soluble antigen, ?dblGATA-1 mice were infected with 2x10 6 pfu of LCMV strain WE and 7 months later analyzed. Animal experiments were approved by the animal care and use committee

. Anti-cd11b, 70); anti-CD11c (N418), anti-Ly6G (Gr-1, RB6-8C5); anti-F4

. Siglec-f, ); anti-CD23 (B3B4); anti-CXCR4 (2B11/CXCR4), and Annexin-V were purchased from BD Pharmingen Anti-Fc?RI? was ordered from eBioscience, anti-APRIL from Stressgen, anti-MOMA-1 from BMA Biomedicals, PNA from Vector As isotype controls rat IgG2a anti-mouse IgG (Molecular Probes) Rabbit anti-mouse Laminin was purchased from Sigma, monoclonal rat anti-mouse MBP from NA Lee and JJ Lee, IgG2b (KLH/G2b-1-2), IgG1 (KLH/G1-2-2) and rabbit IgG (Southern Biotech) Mayo Clinic Arizona, US. Fluorescent dyes conjugated secondary goat-anti rabbit IgG, anti-rat IgG (Molecular Probes), Streptavidin (Molecular Probes or BD) and, pp.281-283

R. Ahmed and D. Gray, Immunological Memory and Protective Immunity: Understanding Their Relation, Science, vol.272, issue.5258, pp.54-60, 1996.
DOI : 10.1126/science.272.5258.54

M. Mamani-matsuda, The human spleen is a major reservoir for long-lived vaccinia virus-specific memory B cells, Blood, vol.111, issue.9, pp.4653-4659, 2008.
DOI : 10.1182/blood-2007-11-123844
URL : https://hal.archives-ouvertes.fr/inserm-00311504

R. A. Manz, A. E. Hauser, F. Hiepe, and A. Radbruch, MAINTENANCE OF SERUM ANTIBODY LEVELS, Annual Review of Immunology, vol.23, issue.1, pp.367-386, 2005.
DOI : 10.1146/annurev.immunol.23.021704.115723

K. A. Fairfax, A. Kallies, S. L. Nutt, and D. M. Tarlinton, Plasma cell development: From B-cell subsets to long-term survival niches, Seminars in Immunology, vol.20, issue.1, pp.49-58, 2008.
DOI : 10.1016/j.smim.2007.12.002

K. G. Smith, A. Light, G. J. Nossal, and D. M. Tarlinton, The extent of affinity maturation differs between the memory and antibody-forming cell compartments in the primary immune response, The EMBO Journal, vol.16, issue.11, pp.2996-3006, 1997.
DOI : 10.1093/emboj/16.11.2996

M. Shapiro-shelef and K. Calame, Regulation of plasma-cell development, Nature Reviews Immunology, vol.247, issue.3, pp.230-242, 2005.
DOI : 10.1084/jem.188.3.515

A. Radbruch, Competence and competition: the challenge of becoming a long-lived plasma cell, Nature Reviews Immunology, vol.106, issue.10, pp.741-750, 2006.
DOI : 10.1038/nri1886

E. J. Blink, Early appearance of germinal center???derived memory B cells and plasma cells in blood after primary immunization, The Journal of Experimental Medicine, vol.158, issue.4, pp.545-554, 2005.
DOI : 10.1084/jem.172.6.1681

R. M. Dilosa, K. Maeda, A. Masuda, A. K. Szakal, and J. G. Tew, Germinal center B cells and antibody production in the bone marrow, J Immunol, vol.146, pp.4071-4077, 1991.

R. Benner, W. Hijmans, and J. J. Haaijman, The bone marrow: the major source of serum immunoglobulins, but still a neglected site of antibody formation, Clin Exp Immunol, vol.46, pp.1-8, 1981.

M. Wols, H. A. Underhill, G. H. Kansas, G. S. Witte, and P. L. , The Role of Bone Marrow-Derived Stromal Cells in the Maintenance of Plasma Cell Longevity, The Journal of Immunology, vol.169, issue.8, pp.4213-4221, 2002.
DOI : 10.4049/jimmunol.169.8.4213

K. Tokoyoda, T. Egawa, T. Sugiyama, B. I. Choi, and T. Nagasawa, Cellular Niches Controlling B Lymphocyte Behavior within Bone Marrow during Development, Immunity, vol.20, issue.6, pp.707-718, 2004.
DOI : 10.1016/j.immuni.2004.05.001
URL : http://doi.org/10.1016/j.immuni.2004.05.001

D. C. Hargreaves, A Coordinated Change in Chemokine Responsiveness Guides Plasma Cell Movements, The Journal of Experimental Medicine, vol.95, issue.1, pp.45-56, 2001.
DOI : 10.4049/jimmunol.165.6.3423

A. E. Hauser, Chemotactic Responsiveness Toward Ligands for CXCR3 and CXCR4 Is Regulated on Plasma Blasts During the Time Course of a Memory Immune Response, The Journal of Immunology, vol.169, issue.3, pp.1277-1282, 2002.
DOI : 10.4049/jimmunol.169.3.1277

Y. Nie, The Role of CXCR4 in Maintaining Peripheral B Cell Compartments and Humoral Immunity, The Journal of Experimental Medicine, vol.129, issue.9, pp.1145-1156, 2004.
DOI : 10.1084/jem.20011626

G. Cassese, Plasma Cell Survival Is Mediated by Synergistic Effects of Cytokines and Adhesion-Dependent Signals, The Journal of Immunology, vol.171, issue.4, pp.1684-1690, 2003.
DOI : 10.4049/jimmunol.171.4.1684

E. Belnoue, APRIL is critical for plasmablast survival in the bone marrow and poorly expressed by early-life bone marrow stromal cells, Blood, vol.111, issue.5, pp.2755-2764, 2008.
DOI : 10.1182/blood-2007-09-110858

O. Connor and B. P. , BCMA Is Essential for the Survival of Long-lived Bone Marrow Plasma Cells, The Journal of Experimental Medicine, vol.157, issue.1, pp.91-98, 2004.
DOI : 10.1038/nsb769

R. J. Lamb, R. J. Capocasale, K. E. Duffy, R. T. Sarisky, and M. L. Mbow, Identification and Characterization of Novel Bone Marrow Myeloid DEC205+Gr-1+ Cell Subsets That Differentially Express Chemokine and TLRs, The Journal of Immunology, vol.178, issue.12, pp.7833-7839, 2007.
DOI : 10.4049/jimmunol.178.12.7833

B. Huard, APRIL secreted by neutrophils binds to heparan sulfate proteoglycans to create plasma cell niches in human mucosa, J Clin Invest, vol.118, pp.2887-2895, 2008.

P. Mhawech-fauceglia, The source of APRIL up-regulation in human solid tumor lesions, Journal of Leukocyte Biology, vol.80, issue.4, pp.697-704, 2006.
DOI : 10.1189/jlb.1105655

E. Mohr, Dendritic Cells and Monocyte/Macrophages That Create the IL-6/APRIL-Rich Lymph Node Microenvironments Where Plasmablasts Mature, The Journal of Immunology, vol.182, issue.4, pp.2113-2123, 2009.
DOI : 10.4049/jimmunol.0802771

M. P. Mcgarry and C. C. Stewart, Murine eosinophil granulocytes bind the murine macrophage-monocyte specific monoclonal antibody F4/80, J Leukoc Biol, vol.50, pp.471-478, 1991.

J. J. Lee, Interleukin-5 Expression in the Lung Epithelium of Transgenic Mice Leads to Pulmonary Changes Pathognomonic of Asthma, The Journal of Experimental Medicine, vol.74, issue.12, pp.2143-2156, 1997.
DOI : 10.1084/jem.184.5.1871

V. T. Chu, P. Enghard, G. Riemekasten, and C. Berek, In Vitro and In Vivo Activation Induces BAFF and APRIL Expression in B Cells, The Journal of Immunology, vol.179, issue.9, pp.5947-5957, 2007.
DOI : 10.4049/jimmunol.179.9.5947

C. Yu, Targeted deletion of a high-affinity GATA-binding site in the GATA-1

J. J. Lee, Defining a Link with Asthma in Mice Congenitally Deficient in Eosinophils, Science, vol.305, issue.5691, pp.1773-1776, 2004.
DOI : 10.1126/science.1099472

C. Berek, A. Berger, and M. Apel, Maturation of the immune response in germinal centers, Cell, vol.67, issue.6, pp.1121-1129, 1991.
DOI : 10.1016/0092-8674(91)90289-B

C. Berek and C. Milstein, Mutation Drift and Repertoire Shift in the Maturation of the Immune Response, Immunological Reviews, vol.81, issue.1, pp.23-41, 1987.
DOI : 10.1038/311727a0

L. A. Spencer and P. Weller, Eosinophils and Th2 immunity: contemporary insights, Immunology and Cell Biology, vol.169, issue.3
DOI : 10.1038/ni.1740
URL : http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3589820

M. Lohning, Long-lived virus-reactive memory T cells generated from purified cytokine-secreting T helper type 1 and type 2 effectors, The Journal of Experimental Medicine, vol.205, issue.1, pp.53-61, 2008.
DOI : 10.1002/(SICI)1521-4141(199801)28:01<390::AID-IMMU390>3.0.CO;2-O

N. Zimmermann, Siglec-F antibody administration to mice selectively reduces blood and tissue eosinophils, Allergy, vol.106, issue.6 Pt 1, pp.1156-1163, 2008.
DOI : 10.1111/j.1398-9995.2008.01709.x

H. Nagase, Expression of CXCR4 in Eosinophils: Functional Analyses and Cytokine-Mediated Regulation, The Journal of Immunology, vol.164, issue.11, pp.5935-5943, 2000.
DOI : 10.4049/jimmunol.164.11.5935

Q. Ma, D. Jones, and T. A. Springer, The Chemokine Receptor CXCR4 Is Required for the Retention of B Lineage and Granulocytic Precursors within the Bone Marrow Microenvironment, Immunity, vol.10, issue.4, pp.463-471, 1999.
DOI : 10.1016/S1074-7613(00)80046-1

M. B. Jordan, D. M. Mills, J. Kappler, P. Marrack, and J. C. Cambier, Promotion of B Cell Immune Responses via an Alum-Induced Myeloid Cell Population, Science, vol.304, issue.5678, pp.1808-1810, 2004.
DOI : 10.1126/science.1089926

A. S. Mckee, Alum Induces Innate Immune Responses through Macrophage and Mast Cell Sensors, But These Sensors Are Not Required for Alum to Act As an Adjuvant for Specific Immunity, The Journal of Immunology, vol.183, issue.7, pp.4403-4414, 2009.
DOI : 10.4049/jimmunol.0900164

B. He, Intestinal Bacteria Induce T Cell-Independent IgA2 Class Switching by Linking Epithelial Cells with Lamina Propria B Cells through APRIL, J Immunol, vol.178, p.28, 2007.

A. Cerutti, Location, location, location: B-cell differentiation in the gut lamina propria, Mucosal Immunology, vol.194, issue.1, pp.8-10, 2008.
DOI : 10.1038/mi.2007.8

L. Juhlin and G. Michaelsson, A NEW SYNDROME CHARACTERISED BY ABSENCE OF EOSINOPHILS AND BASOPHILS, The Lancet, vol.309, issue.8024, pp.1233-1235, 1977.
DOI : 10.1016/S0140-6736(77)92440-0

S. P. Hogan, Recent Advances in Eosinophil Biology, International Archives of Allergy and Immunology, vol.143, issue.1
DOI : 10.1159/000101398