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Extrafollicular Activation of Lymph Node B Cells by Antigen-Bearing Dendritic Cells

2006; American Association for the Advancement of Science; Volume: 312; Issue: 5780 Linguagem: Inglês

10.1126/science.1125703

1095-9203

Hai Qi, Jackson G. Egen, Alex Y. Huang, Ronald N. Germain,

Cell Adhesion Molecules Research

In contrast to naïve T cells that recognize short antigen-derived peptides displayed by specialized antigen-presenting cells, immunoglobulin receptors of B lymphocytes primarily recognize intact proteins. How and where within a lymph node such unprocessed antigens become available for naïve B cell recognition is not clear. We used two-photon intravital imaging to show that, after exiting high-endothelial venules and before entry into lymph node follicles, B cells survey locally concentrated dendritic cells. Engagement of the B cell receptor by the dendritic cell (DC)-associated antigen leads to lymphocyte calcium signaling, migration arrest, antigen acquisition, and extrafollicular accumulation. These findings suggest a possible role for antigen-specific B-DC interactions in promoting T cell-dependent antibody responses in vivo.