| Summary: | The HIV-1 envelope protein gp120 is both the target of neutralizing antibodies and a
major focus of vaccine efforts; however how it is delivered to B cells to elicit an
antibody response is unknown. Here, we show that following local gp120 injection
lymph node (LN) SIGN-R1+ sinus macrophages located in
interfollicular pockets and underlying SIGN-R1+ macrophages form a
cellular network that rapidly captures gp120 from the afferent lymph. In contrast,
two other antigens, phycoerythrin and hen egg lysozyme, were not captured by these
cells. Intravital imaging of mouse LNs revealed persistent, but transient
interactions between gp120 bearing interfollicular network cells and both trafficking
and LN follicle resident gp120 specific B cells. The gp120 specific, but not the
control B cells repetitively extracted gp120 from the network cells. Our findings
reveal a specialized LN antigen delivery system poised to deliver gp120 and likely
other pathogen derived glycoproteins to B cells.
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