When HIV infects macrophages, it doesn't kill or destroy them immediately, but once it infects T-cells, they're destroyed. Why is that? As in why does it destroy T-cells and not macrophages or other cells.
This process does not destroy the macrophages. Unlike macrophages, helper T cells are destroyed.
From this article:
Researchers found that when the virus productively infects the few permissive CD4 T cells present, death occurs through apoptosis mediated by an enzyme called caspase-3. But when HIV abortively infects nonpermissive CD4 T cells, death occurs by pyroptosis, which depends on the activation of caspase-1. It turns out that the vast majority—roughly 95 percent—of CD4 T cell death in lymphoid tissues is driven by caspase-1-mediated pyroptosis.
When it comes to macrophages, however:
macrophages are much more resistant to cytopathic effects of lentiviral replication than for example activated CD4+ T cells [23, 24, 25], and HIV-1 has evolved sophisticated mechanisms to prolong the life span of infected macrophages [24, 26]. Especially long-lived macrophages may therefore harbor the virus for long time periods, thus constituting HIV-1 reservoirs and posing a major obstacle to virus eradication from infected individuals.
