Diesel exhaust particles modify natural killer cell function and cytokine release

Area of Science:

• Immunology
• Environmental Health

Background:

• Natural killer (NK) cells are crucial lymphocytes in the nasal mucosa, bridging innate and adaptive immunity.
• NK cells perform direct cytotoxicity and cytokine release, vital for combating viral infections and cancer.
• Nasal NK cells are exposed to inhaled pollutants like diesel exhaust particles (DEP).

Purpose of the Study:

• Investigate the impact of diesel exhaust particles (DEP) on NK cell function during viral infections.
• Determine how DEP exposure affects NK cell-mediated cytotoxicity and cytokine release.

Main Methods:

• NK cells isolated from healthy volunteers.
• Cells stimulated with polyinosinic:polycytidylic acid (pI:C) (viral mimetic) and/or DEP.
• Analyzed surface markers, cytokine production, gene expression, and cytotoxic function.

Main Results:

• DEP exposure, with viral stimuli, increased certain cytokine releases (IL-1β, IL-8, TNF-α) but decreased cytotoxic markers (granzyme B, perforin) and function.
• DEP alone reduced IL-1β, IL-8, and TNF-α release compared to viral stimuli alone.
• DEP significantly reduced NK cell cytotoxicity and CD16 expression.

Conclusions:

• DEP exposure may reduce NK cell's ability to kill virus-infected cells.
• This impairment in NK cell function could increase susceptibility to viral infections.
• DEP's impact on NK cell cytotoxicity warrants further investigation in respiratory health.