The classical (CD14++CD16-), intermediate (CD14++CD16+), and non-classical (CD14 + CD16++) subsets display varying responses to viral exposure, influencing the kinetics of infection and subsequent immune activation.[15] Monocytes, particularly the classical subset, express high levels of CD4 and CCR5 receptors, rendering them susceptible to R5-tropic HIV strains. Here, CD4 is linked to infection.