Tiny filaments may be transporting material between immune cells – and even trafficking 'surfing bacteria' along their surface.

It has recently become clear that cells of the immune system link to one another through fine filaments or 'nanotubes'. Daniel Davis and colleagues at Imperial College London have now found that at least two distinct types of nanotube exist, with different transport functions.

The group identified two types spanning macrophages, immune cells that ingest and digest pathogens such as bacteria. The larger type contained actin and microtubule fibres, and transported cellular components such as membrane-bound vesicles; the thinner variety contained just actin, and did not contain vesicles but did transport bacteria along their surfaces – a process dubbed 'surfing'.

This research highlights an unexpectedly complex set of physical contacts between macrophages, of potential importance in our immune defences.

This research was supported by the Wellcome Trust and others.

External link

• Önfelt B et al. Structurally distinct membrane nanotubes between human macrophages support long-distance vesicular traffic or surfing of bacteria. J Immunol 2006;177(12):8476–83.