Rapid Decrease of CD16 (FcγRIII)‎ Expression on Heat-Shocked Neutrophils and Their Recognition by Macrophages

Abstract EN

Accumulation of neutrophils in the site of inflammation is a typical mechanism of innate immunity.

The accumulated neutrophils are exposed to stressogenic factors usually associated with inflammation.

Here, we studied response of human peripheral blood neutrophils subjected to short, febrile-range heat stress.

We show that 90 min heat stress slowed down the spontaneous apoptosis of neutrophils.

In the absence of typical markers of apoptosis the heat-shocked neutrophils induced antiinflammatory effect in human monocyte-derived macrophages (hMDMs), yet without being engulfed.

Importantly, the expression of FcγRIII (CD16) was sharply reduced.

Surprisingly, concentration of the soluble CD16 did not change in heat-shocked neutrophil supernates indicating that the reduction of the cell surface CD16 was achieved mainly by inhibition of fresh CD16 delivery.

Inhibitors of 90 kDa heat shock protein (HSP90), a molecular chaperone found in membrane platforms together with CD16 and CD11b, significantly increased the observed effects caused by heat shock.

The presented data suggest a novel systemic aspect of increased temperature which relies on immediate modification by heat of a neutrophil molecular pattern.

This effect precedes cell death and may be beneficial in the initial phase of inflammation providing a nonphlogistic signal to macrophages before it comes from apoptotic cells.