Posts Tagged ‘neutrofilos’

Células Neutrófilos caçando e matando invasores bactérias dentro do corpo humano (video)

Tuesday, October 13th, 2020
Crawling Neutrophil Chasing a Bacterium
Blausen 0676 Neutrophil (crop).png
Neutrophil

Em 2004 foi descoberta uma terceira estratégia dos neutrófilos para conter e matar patógenos, a emissão de armadilhas extracelulares dos neutrófilos (NETs). Esse mecanismo consiste na emissão de rede pelo granulócito contendo enzimas dos grânulos citoplasmático e o DNA da célula. Essa rede, então, é capaz de aprisionar e eliminar agentes infecciosos.

Neutrophils are a type of phagocyte and are normally found in the bloodstream. During the beginning (acute) phase of inflammation, particularly as a result of bacterial infection, environmental exposure,[6] and some cancers,[7][8] neutrophils are one of the first responders of inflammatory cells to migrate toward the site of inflammation. They migrate through the blood vessels and then through interstitial tissue, following chemical signals such as Interleukin-8 (IL-8), C5afMLPLeukotriene B4, and H2O2[9] in a process called chemotaxis. They are the predominant cells in pus, accounting for its whitish/yellowish appearance.[10]

Neutrophils are recruited to the site of injury within minutes following trauma and are the hallmark of acute inflammation;[11] however, due to some pathogens being indigestible, they can be unable to resolve certain infections without the assistance of other types of immune cells.

Neutrophils (also known as neutrocytes or heterophils) are the most abundant type of granulocytes and make up 40% to 70% of all white blood cells in humans.[1] They form an essential part of the innate immune system, with their functions varying in different animals

Na figura abaixo, a estonteante capacidade inteligente desta célula: para se locomover no meios das células, onde tem filamentos ligando as células na frente, ela emite enzimas que vão na frente desfazendo os filamentos para ela passar! E como ela sabe que além daquelas células tem bactérias escondidas?! Se ela nem olhos tem, como fica sabendo que há invasores?!

Neutrophil granulocyte migrates from the blood vessel to the matrix, secreting proteolytic enzymes, in order to dissolve intercellular connections (to the improvement of its mobility) and envelop bacteria through phagocytosis. – By !Original: Dr. med. Mario Schubert, Heidelberg, GermanyVector: Mrmw – Own work based on: NeutrophilerAktion.png:, CC0, https://commons.wikimedia.org/w/index.php?curid=61571220

Neutrophils.jpg
Neutrophil white blood cells (leukocytes) – By Dr Graham Beards – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=20521666

Descoberta sobre origens do sistema imunologico!

No paper abaixo intui uma possível explicação para este não resolvido problema de como se originou e como funciona o sistema imunológico. Vou registrar isso no próximo artigo. Trata-se da NET:

Neutrophil Extracellular Traps Kill Bacteria

  •  See all authors and affiliationsScience  05 Mar 2004:
  • Vol. 303, Issue 5663, pp. 1532-1535
  • DOI: 10.1126/science.1092385
  • Science Magazine

https://science.sciencemag.org/content/303/5663/1532

Abstract

Neutrophils engulf and kill bacteria when their antimicrobial granules fuse with the phagosome. Here, we describe that, upon activation, neutrophils release granule proteins and chromatin that together form extracellular fibers that bind Gram-positive and -negative bacteria. These neutrophil extracellular traps (NETs) degrade virulence factors and kill bacteria. NETs are abundant in vivo in experimental dysentery and spontaneous human appendicitis, two examples of acute inflammation. NETs appear to be a form of innate response that binds microorganisms, prevents them from spreading, and ensures a high local concentration of antimicrobial agents to degrade virulence factors and kill bacteria.