In this three-dimensional image stack rendering, HIV virions (red) are localized on filopodial bridges between an infected T cell (gold) and an uninfected fetal astrocyte (blue). Astrocytes are star-shaped glial cells found in the brain and spinal cord. Filopodia are slender cytoplasmic projections that extend out from migrating cells, acting as antennae to probe the surrounding environment or in this case, apparently, serve as a passageway for invading virions.
— Scott LaFee