**Neutrophil Extracellular Traps in Infectious Human Diseases**

Marcin Zawrotniak, Andrzej Kozik and Maria Rapala‐Kozik

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.68443

#### **Abstract**

Neutrophils, as the main cells of the first line of host defense against microbial pathogens, are responsible for pathogen recognition, inhibition of pathogen spreading into the host tissue, and finally, killing the invader cells. Neutrophils carry out these functions via numerous mechanisms, including a relatively recently described activity based on a release of neutrophil extracellular traps (NETs), a process called netosis. NETs are structures composed of DNA backbone, decorated with antimicrobial factors, derived from neutrophil granules. The structure of NETs and their enzymatic and microbicidal inclusions enable efficient trapping and killing of microorganisms within the neutrophil extracellular space. However, the efficiency of NETs depends on neutrophil ability to recognize pathogen signals and to trigger rapid responses. In this chapter, we focus on possible pathways involved in the release of NETs and summarize the current knowledge on triggers of this process during bacterial, fungal, protozoan, and viral infections. We also consider the mechanisms used by microorganisms to evade NET‐killing activity and analyze the harmful potential of NETs against the host cells and the contribution of NETs to noninfectious human diseases.

**Keywords:** neutrophil extracellular traps, netosis, receptors, microbial evasion of NETs, autoimmune diseases
