When dendritic cells are young and immature, they're excellent at phagocytosis, constantly eating large amounts of protein found in the interstitial fluid.
Macrophages, T-helper cells, and dendritic cells are all involved in the immune response and all have CD4 molecules; therefore they can be targeted by HIV.
They form stronger connections with each other than with other neurons and they develop more dendritic spines: protrusions that help neurons talk to each other.