Preface

Polymorphnuclear cells (or neutrophils) are the most abundant type of immune cells in the blood and play an integral role in innate and adaptive immunity towards various infectious and non-infectious triggers. These cells have the capability to perform various effector functions such as phagocytosis, degranulation, motility/chemotaxis, and the recently discovered function called neutrophil extracellular traps formation and subsequent microbial killing. *Neutrophils* provides recent evidence regarding the various properties of these immune cells in relation to various disease conditions aimed at future therapeutic targets.

**Chapter 1** (Introductory Chapter: Background Summary Regarding Neutrophils) briefly discusses the basic effector functions of neutrophils, which provide the basis for the upcoming chapters in the book.

**Chapter 2** (Cannabinoid Receptors as Regulators of Neutrophil Activity in Inflammatory Diseases) discusses how cannabinoids (binding through their receptors: CR-1 and -2) can modulate various activities of neutrophils, and act as a therapeutic target for various neutrophil-related inflammatory (e.g. arthritis, ischemic diseases, and colitis) and infectious (e.g. sepsis and mycobacterial infection) conditions.

**Chapter 3** (Neutrophil Activation by Antibody Receptors) discusses the role of neutrophils in the adaptive immune response through their interactions with immunoglobulins (mainly IgG) secreted by B-cells. The main types of FcγRs located on neutrophils and how particular FcγRs can activate various signaling pathways to promote unique effector cell functions are also discussed in this chapter.

**Chapter 4** (Remodeling of Phenotype CD16+ CD11b+ Neutrophilic Granulocytes in Acute Viral and Acute Bacterial Infections) discusses the different expression patterns of the membrane receptors CD16 and CD11b in normal and pathological conditions such as in patients with acute viral and acute bacterial tonsillitis. The differential membranous expression profile of these receptors on the neutrophils may help in the early-stage diagnosis of these conditions.

**Chapter 5** (Essence of Reducing Equivalent Transfer Powering Neutrophil Oxidative Microbicide Action and Chemiluminescence) discusses the physics of the NADPH oxidase system and the detection of the generated reactive oxygen species using various chemiluminigenic probes for circulating blood neutrophils, which can aid in *in vivo* state of host inflammatory activation.

We hope that the recent evidence described in this book provides a better understanding of the role of this important immune cell in various disease conditions and forms the basis for future research activities aimed at providing better therapeutic approaches to treat various disease conditions.
