Measles Virus Infects and Programs MAIT Cells for Apoptosis

Area of Science:

• Immunology
• Virology
• Infectious Diseases

Background:

• Measles virus (MeV) is known to infect and deplete CD150+ memory T cells, causing immune amnesia.
• The susceptibility of innate, memory-like T cells to MeV infection remained uncharacterized.

Purpose of the Study:

• To investigate whether MeV targets innate, memory-like T cells, specifically mucosa-associated invariant T (MAIT) cells and invariant natural killer T (iNKT) cells.
• To determine the susceptibility of MAIT cells to MeV infection and subsequent cell death.

Main Methods:

• Analysis of CD150 expression on human peripheral blood and hepatic MAIT cells and iNKT cells.
• In vitro exposure of MAIT cells to MeV.
• Assessment of MAIT cell infection and apoptosis following MeV exposure.

Main Results:

• MAIT cells and iNKT cells express high levels of CD150, exceeding that of other lymphocyte subsets.
• MAIT cells are efficiently infected by MeV.
• MeV infection leads to rapid apoptosis of MAIT cells.

Conclusions:

• This study reports the direct infection of MAIT cells by MeV, a novel finding.
• The elimination of MAIT cells by MeV may contribute to measles-associated immunosuppression.
• MAIT cell depletion could increase vulnerability to secondary, unrelated infections.