Mechanisms of HIV entry into the CNS: increased sensitivity of HIV infected CD14+CD16+ monocytes to CCL2 and key roles of CCR2, JAM-A, and ALCAM in diapedesis

PLoS One. 2013 Jul 26;8(7):e69270. doi: 10.1371/journal.pone.0069270. Print 2013.


As HIV infected individuals live longer, the prevalence of HIV associated neurocognitive disorders is increasing, despite successful antiretroviral therapy. CD14(+)CD16(+) monocytes are critical to the neuropathogenesis of HIV as they promote viral seeding of the brain and establish neuroinflammation. The mechanisms by which HIV infected and uninfected monocytes cross the blood brain barrier and enter the central nervous system are not fully understood. We determined that HIV infection of CD14(+)CD16(+) monocytes resulted in their highly increased transmigration across the blood brain barrier in response to CCL2 as compared to uninfected cells, which did not occur in the absence of the chemokine. This exuberant transmigration of HIV infected monocytes was due, at least in part, to increased CCR2 and significantly heightened sensitivity to CCL2. The entry of HIV infected and uninfected CD14(+)CD16(+) monocytes into the brain was facilitated by significantly increased surface JAM-A, ALCAM, CD99, and PECAM-1, as compared to CD14(+) cells that are CD16 negative. Upon HIV infection, there was an additional increase in surface JAM-A and ALCAM on CD14(+)CD16(+) monocytes isolated from some individuals. Antibodies to ALCAM and JAM-A inhibited the transmigration of both HIV infected and uninfected CD14(+)CD16(+) monocytes across the BBB, demonstrating their importance in facilitating monocyte transmigration and entry into the brain parenchyma. Targeting CCR2, JAM-A, and ALCAM present on CD14(+)CD16(+) monocytes that preferentially infiltrate the CNS represents a therapeutic strategy to reduce viral seeding of the brain as well as the ongoing neuroinflammation that occurs during HIV pathogenesis.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigens, CD / metabolism*
  • Blood-Brain Barrier / drug effects
  • Blood-Brain Barrier / immunology
  • Blood-Brain Barrier / pathology
  • Blood-Brain Barrier / virology
  • Cell Adhesion Molecules / metabolism*
  • Cell Adhesion Molecules, Neuronal / metabolism*
  • Cell Membrane / drug effects
  • Cell Membrane / metabolism
  • Central Nervous System / drug effects
  • Central Nervous System / pathology
  • Central Nervous System / virology*
  • Chemokine CCL2 / pharmacology*
  • Demography
  • Fetal Proteins / metabolism*
  • HIV Infections / immunology
  • HIV Infections / pathology
  • HIV Infections / virology*
  • HIV-1 / drug effects
  • HIV-1 / physiology
  • Humans
  • Lipopolysaccharide Receptors / metabolism
  • Middle Aged
  • Monocytes / drug effects
  • Monocytes / pathology
  • Monocytes / virology*
  • Receptors, CCR2 / metabolism*
  • Receptors, Cell Surface / metabolism*
  • Receptors, IgG / metabolism
  • Transendothelial and Transepithelial Migration / drug effects*
  • Virus Internalization / drug effects


  • ALCAM protein, human
  • Antigens, CD
  • CCR2 protein, human
  • Cell Adhesion Molecules
  • Cell Adhesion Molecules, Neuronal
  • Chemokine CCL2
  • F11R protein, human
  • Fetal Proteins
  • Lipopolysaccharide Receptors
  • Receptors, CCR2
  • Receptors, Cell Surface
  • Receptors, IgG