Thursday, December 14, 2017

Nature: Lactobacillus casei Confers Broad Protection Against Influenza A Virus (in Mice)

Credit WIkipedia


One of the things you don't often see in this blog are the all-too-common claims made by the purveyors of certain foods, and supplements - or by media health writers with a rapidly approaching deadline - of the miraculous commonly available cures ignored by western medicine.
It isn't that I don't believe some foods or supplements could prove beneficial against specific medical problems, its just that most of these stories are - at best - anecdotal in nature, and provide little in the way of real evidence. 
These topics haven't been entirely verboten in this blog, since we looked at research back in 2010 (see Study: Probiotic Therapy Cuts VAP Risk) on the effects of daily probiotic therapy on people on long-term ventilator support. I've also written several blogs on studies that have looked at the benefits of Vitamin D (see Study: Vitamin D And The Innate Immune System.)
But as much as I'd like to believe there are safe, effective, over-the-counter cures for many serious medical conditions, most claims of this sort carry little if any supporting evidence.
However, when a serious study - funded by NIAID, the NIH, the DOD, etc. -  published in Nature's Scientific Reports, finds a potential protective effect against influenza from a common probiotic, it is worth a look.

The open-access (and at times technical) study from Georgia State University is called:
Article | Open
Heat-killed Lactobacillus casei confers broad protection against influenza A virus primary infection and develops heterosubtypic immunity against future secondary infection 
Yu-Jin Jung, Young-Tae Lee, Vu Le Ngo, Young-Hee Cho, Eun-Ju Ko, Sung-Moon Hong, Ki-Hye Kim, Ji-Hun Jang, Joon-Suk Oh, Min-Kyung Park, Cheol-Hyun Kim, Jun Sun & Sang-Moo Kang


Lactic acid bacteria (LAB) are the common probiotics. Here, we investigated the antiviral protective effects of heat-killed LAB strain Lactobacillus casei DK128 (DK128) on influenza viruses.

Intranasal treatment of mice with DK128 conferred protection against different subtypes of influenza viruses by lessening weight loss and lowering viral loads. Protection via heat-killed DK128 was correlated with an increase in alveolar macrophage cells in the lungs and airways, early induction of virus specific antibodies, reduced levels of pro-inflammatory cytokines and innate immune cells. 

Importantly, the mice that were protected against primary viral infection as a result of heat-killed DK128 pretreatment developed subsequent heterosubtypic immunity against secondary virus infection. For protection against influenza virus via heat-killed DK128 pretreatment, B cells and partially CD4 T cells but not CD8 T cells were required as inferred from studies using knockout mouse models. 

Our study provides insight into how hosts can be equipped with innate and adaptive immunity via heat-killed DK128 treatment to protect against influenza virus, supporting that heat-killed LAB may be developed as anti-virus probiotics.
         (Continue . . . )

From Georgia State University we get the following press release, after which I'll return with more.
Lactic acid bacteria can protect against influenza a virus 
Date:December 13, 2017
Source:Georgia State University

Summary:Lactic acid bacteria, commonly used as probiotics to improve digestive health, can offer protection against different subtypes of influenza A virus, resulting in reduced weight loss after virus infection and lower amounts of virus replication in the lungs, according to a new study. 


Lactic acid bacteria, commonly used as probiotics to improve digestive health, can offer protection against different subtypes of influenza A virus, resulting in reduced weight loss after virus infection and lower amounts of virus replication in the lungs, according to a study led by Georgia State University.

Influenza virus can cause severe respiratory disease in humans. Although vaccines for seasonal influenza viruses are readily available, influenza virus infections cause three to five million life-threatening illnesses and 250,000 to 500,000 deaths worldwide during epidemics. Pandemic outbreaks and air transmission can rapidly cause severe disease and claim many more human lives worldwide. This occurs because current vaccines are effective only when vaccine strains and circulating influenza viruses are well matched.

Influenza A virus, which infects humans, birds and pigs, has many different subtypes based on hemagglutinin (HA) and neuraminidase (NA) proteins on the surface of the virus. There are 18 different HA and 11 different NA subtype molecules identified, which indicates numerous HA and NA influenza virus combinations. As a result, it's important to find ways to provide broad protection against influenza viruses, regardless of the virus strain.

Fermented vegetables and dairy products contain a variety of lactic acid bacteria, which have a number of health benefits in addition to being used as probiotics. Studies have found some lactic acid bacteria strains provide partial protection against bacterial infectious diseases, such as Streptococcus pneumoniae, as well as cold and influenza viruses.

This study investigated the antiviral protective effects of a heat-killed strain of lactic acid bacteria, Lactobacillus casei DK128 (DK128), a promising probiotic isolated from fermented vegetables, on influenza viruses.

Mice pretreated with DK128 intranasally and infected with influenza A virus showed a variety of immune responses that are correlated with protection against influenza virus, including an increase in the alveolar macrophage cells in the lungs and airways, early induction of virus specific antibodies and reduced levels of pro-inflammatory cytokines and innate immune cells. The mice also developed immunity against secondary influenza virus infection by other virus subtypes. The findings are published in the journal Scientific Reports.

"We found that pretreating the mice with heat-killed Lactobacillus casei DK128 bacteria made them resistant to lethal primary and secondary influenza A virus infection and protected them against weight loss and mortality," said Dr. Sang-Moo Kang, lead author of the study and professor in the Institute for Biomedical Sciences at Georgia State. "Our results are highly significant because mice pretreated with DK128 had 100 percent survival and prevention of weight loss.
This strain of lactic acid bacteria also equipped mice with cross-protective immunity against secondary lethal infection with influenza virus. Protection against influenza virus infection was not specific to a particular strain of influenza.

"Our study provides evidence that heat-killed lactic acid bacteria could potentially be administered via a nasal spray as a prophylactic drug against non-specific influenza virus infections."
(Continue . . . )

The idea of crafting an antiviral from a probiotic isn't all that crazy. After all, Tamiflu (tm) is made from shakimic acid derived from the Chinese star anise plant. 
But before anyone decides that eating kimchi or downing handfuls of probiotic capsules obviates the need for getting a flu vaccine, or taking antivirals when infected, the words `potential' and `potentially' loom large in this study. 
Not only was this research conducted on mice, there are questions remaining on what would be an effective dose and best delivery method for humans.

That said, this is fascinating research that could conceivably yield new and effective treatments (or preventatives) for flu down the road, and as such is well worth our attention.

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