J Virol. Influenza virus directly infects human natural killer cells and induces cell apoptosis.

[Giuseppe]

J Virol. 2009 Jul 8. [Epub ahead of print]

Influenza virus directly infects human natural killer cells and induces cell apoptosis.

Mao H, Tu W, Qin G, Law HK, Sia SF, Chan PL, Liu Y, Lam KT, Zheng J, Peiris M, Lau YL. Department of Paediatrics & Adolescent Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, PR China; Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, PR China; HKU-Pasteur Research Centre, The University of Hong Kong, Hong Kong SAR, PR China.


Influenza is an acute respiratory viral disease that is transmitted in the first few days of infection. Evasion of host innate immune defenses including natural killer (NK) cells would be important for its success as a viral pathogen of humans and other animals. NK cells will encounter influenza viruses within the microenvironment of infected cells and are important for host innate immunity during influenza infection. It is therefore important to investigate the direct effects of influenza virus on NK cells. In this study, we demonstrated for the first time that influenza virus directly infected and replicated in primary human NK cells. Viral entry into NK cells was mediated by both clathrin- and caveolin-dependent endocytosis rather than through macropinocytosis, and was dependent on the sialic acids on cell surface. In addition, influenza virus infection induced marked apoptosis of NK cells. Our findings suggest that influenza virus can directly target and kill NK cells, a potential novel strategy of influenza virus to evade NK cell innate immune defense which is likely to facilitate viral transmission and may also contribute to virus pathogenesis.

PMID: 19587043 [PubMed - as supplied by publisher]
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[gsgs]

Re: J Virol. Influenza virus directly infects human natural killer cells and induces cell apoptosis.

uhh, any other viruses who do this ?
Any flu does it or only some strains ?
Is it connected to Cytokene Storm ?

 

[kiwibird]

Re: J Virol. Influenza virus directly infects human natural killer cells and induces cell apoptosis.

Natural killer cells (or NK cells) are a type of cytotoxic lymphocyte that constitute a major component of the innate immune system. NK cells play a major role in the rejection of tumors and cells infected by viruses. The cells kill by releasing small cytoplasmic granules of proteins called perforin and granzyme that cause the target cell to die by apoptosis or necrosis.

NK-cells are defined as large granular lymphocytes (LGL) and constitute the third kind of cells differentiated from the common lymphoid progenitor generating B and T lymphocytes.[1] They do not express T-cell antigen receptors (TCR) or Pan T marker CD3 or surface immunoglobulins (Ig) B cell receptor but that usually express the surface markers CD16 (FcγRIII) and CD56 in humans, and NK1.1/NK1.2 in certain strains of mice. Up to 80% of NK cells also express CD8.

They were named "natural killers" because of the initial notion that they do not require activation in order to kill cells that are missing "self" markers of major histocompatibility complex (MHC) class I.

http://en.wikipedia.org/wiki/Nk_cells

Does this information change the way we will have to think about cytokine storms?

 

[gsgs]

Re: J Virol. Influenza virus directly infects human natural killer cells and induces cell apoptosis.

full article here:
http://jvi.asm.org/cgi/reprint/JVI.00805-09v1?view=long&pmid=19587043


A/HK/54/1998(H1N1) was used
HIV,HSV and ECTV also use this strategy

 

[AlaskaDenise]

Re: J Virol. Influenza virus directly infects human natural killer cells and induces cell apoptosis.

....influenza virus infection induced marked apoptosis of NK cells. Our findings suggest that influenza virus can directly target and kill NK cells, a potential novel strategy of influenza virus to evade NK cell innate immune defense....

I'm confident that.....we'll never be able to outsmart this virus.

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