Single Particle Tracking reveals two distinct environments for CD4 receptors at the surface of living T lymphocytes

We investigated the lateral diffusion of the HIV receptor CD4 at the surface of T lymphocytes at 20 °C and 37 °C by Single Particle Tracking using Quantum Dots. We found that the receptors presented two major distinct behaviors that were not equally affected by temperature changes. About half of the receptors showed a random diffusion with a diffusion coefficient increasing upon raising the temperature. The other half of the receptors was permanently or transiently confined with unchanged dynamics on raising the temperature. These observations suggest that two distinct subpopulations of CD4 receptors with different environments are present at the surface of living T lymphocytes.

► We studied the diffusion of single CD4 receptors on living lymphocytes.
► This study reveals that CD4 receptors have either a random or confined diffusion.
► The dynamics of unconfined CD4 receptors was accelerated by a temperature raise.
► The dynamics of confined CD4 receptors was unchanged by a temperature raise.
► Our results suggest the existence of two different environments for CD4 receptors.