Social networking of human neutrophils within the immune system

Abstract

It is now widely recognized that neutrophils are highly versatile and sophisticated cells that display de novo synthetic capacity and may greatly extend their lifespan. In addition, concepts such as “neutrophil heterogeneity” and “neutrophil plasticity” have started to emerge, implying that, under pathological conditions, neutrophils may differentiate into discrete subsets defined by distinct phenotypic and functional profiles. A number of studies have shown that neutrophils act as effectors in both innate and adaptive immunoregulatory networks. In fact, once recruited into inflamed tissues, neutrophils engage into complex bidirectional interactions with macrophages, natural killer, dendritic and mesenchymal stem cells, B and T lymphocytes, or platelets. As a result of this cross-talk, mediated either by contact-dependent mechanisms or cell-derived soluble factors, neutrophils and target cells reciprocally modulate their survival and activation status. Altogether, these novel aspects of neutrophil biology have shed new light not only on the potential complex roles that neutrophils play during inflammation and immune responses, but also in the pathogenesis of several inflammatory disorders including infection, autoimmunity, and cancer.

Platelet microparticles are internalized in neutrophils via the concerted activity of 12-lipoxygenase and secreted phospholipase A 2 -IIA

“…For instance, in rheumatoid arthritis (RA), the most common form of autoimmune joint inflammation, neutrophils are represented preponderantly in the diseased joint fluid and display a prolonged lifespan and reduced migratory activity, suggesting the accumulation of factor(s) in RA that promote neutrophil plasticity (23)(24)(25).…”

Feedback Amplification of Neutrophil Function

“…IL-18-activated NK cells can prolong neutrophil survival through the production of GM-CSF and IFNγ [92]. For further cooperative amplification loops between neutrophils and T cells or NK cells, we refer to previous review articles [79,93].…”

Human Vγ9/Vδ2 T cells: Innate adaptors of the immune system

“…Neutrophils turn out to be far more versatile and sophisticated than originally perceived and have been shown to engage in complex mutual interactions with other immune and non-immune cells to regulate acute inflammation as well as resolution and tissue repair [77,78]. As a result of this crosstalk, neutrophils receive potent signals that trigger a substantial extension of their life span and allow them to acquire distinct phenotypes and functions including the capacity to facilitate monocyte differentiation and DC maturation, and to interact with T cells [78][79][80]. It is this intriguing APC-like aspect of neutrophil biology that is most relevant to this review.…”