Figure 9.15. Immune complexes bound to follicular dendritic cells form iccosomes, which are released and can be taken up by B cells in the germinal center.

Figure 9.15Immune complexes bound to follicular dendritic cells form iccosomes, which are released and can be taken up by B cells in the germinal center

Follicular dendritic cells have a prominent cell body and many dendritic processes. Immune complexes, bound to complement and Fc receptors on the follicular dendritic cell surface, become clustered, forming prominent ‘beads’ along the dendrites. An intermediate form of follicular dendritic cell is shown (left panel) with both straight filiform dendrites and those that are becoming beaded. These beads are shed from the cell as iccosomes (immune complexcoated bodies), which can bind (center panel) and be taken up by B cells in the germinal center (right panel). In the center and right panels, the iccosome has been formed with immune complexes containing horseradish peroxidase, which is electrondense and thus appears dark in the transmission electron micrographs. Photographs courtesy of A.K. Szakal, Annual Reviews of Immunology 1989; 7:91-109.

From: B-cell activation by armed helper T cells

Cover of Immunobiology
Immunobiology: The Immune System in Health and Disease. 5th edition.
Janeway CA Jr, Travers P, Walport M, et al.
New York: Garland Science; 2001.
Copyright © 2001, Garland Science.

NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.