Cellular targets of HIV: Which of the following cell types can be infected by HIV during the course of disease and contribute to viral persistence or pathology?

Introduction / Context:
HIV exhibits tropism for cells expressing CD4 and appropriate co-receptors (CCR5 or CXCR4). Beyond classical CD4+ T lymphocytes, the virus can involve other immune and neural cells, shaping clinical manifestations and reservoir biology.

Given Data / Assumptions:

• CD4+ T cells are the principal targets for productive infection.
• Cells of the monocyte–macrophage lineage, including microglia in the central nervous system, can be infected and act as reservoirs.
• M cells in mucosal tissues facilitate translocation and may be permissive to or involved in the entry and transfer of HIV across mucosal barriers.

Concept / Approach:
Evaluate each cell type for susceptibility or involvement with HIV. Microglia and CD4+ T cells are well-established. M cells participate in mucosal trafficking; experimental and ex vivo data support their role in facilitating HIV passage and potential infection dynamics at mucosal surfaces.

Step-by-Step Solution:
Confirm infection of CD4+ T lymphocytes as canonical.Acknowledge CNS involvement via infected microglia and macrophages, contributing to neurocognitive disorders.Recognize mucosal entry pathways where M cells can transport virus across epithelium and contribute to local infection processes.Select ‘‘All of these’’ since each listed cell type is implicated in HIV pathogenesis or entry.

Verification / Alternative check:
Neuropathology of HIV demonstrates microglial infection; mucosal transmission studies emphasize specialized epithelial and immune cell interactions during early infection.

Why Other Options Are Wrong:
Individual options are true but incomplete; erythrocytes lack nuclei and are not infected, hence included as a distractor only and not in the correct aggregate.

Common Pitfalls:
Overlooking non-T-cell reservoirs such as macrophages/microglia; assuming mucosal transport cells play no role in early infection events.

Final Answer:
All of these.