Spatiotemporal Basis of Innate and Adaptive Immunity in Secondary Lymphoid Tissue: Video 13

A video from the 2014 review by Hai Qi, Wolfgang Kastenmüller, and Ronald N. Germain, "Spatiotemporal Basis of Innate and Adaptive Immunity in Secondary Lymphoid Tissue," from the Annual Review of Cell and Developmental Biology.

Shown: The calcium responses of immigrant Ag-specific B cells engaging Ag-bearing DCs immediately after exiting HEVs

(a) Immediately after exiting a HEV, an MD4 B cell (red, pointed by an arrowhead while still inside the HEV) engages an HEL-DC (blue) and shows an abrupt increase in Fluo-4 fluorescence, indicating elevation of intracellular [Ca²⁺]. (b) The same video is played again showing magnified views (2×), including freeze frames, to highlight the first DC contact and the subsequent onset of calcium flux by the MD4 cell. Scale bar: 20 µm.

Original publication: Qi H, Egen JG, Huang AY, Germain RN. 2006. Extrafollicular activation of lymph node B cells by antigen-bearing dendritic cells. Science 312:1672–76