Probiotics Protect Against Flu
The probiotics that millions of Americans take to improve their digestive health can also help protect them from against different variations of influenza A virus — the flu — says a study from Georgia State University.
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. Researchers have identified 18 different HA and 11 different NA subtype molecules.
This means that the two subtypes can combine to form many variations of flu, which changes from season to season, and is why it is important to find ways to provide protection, regardless of the virus strain.
The new 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 were pretreated with DK128 intranasally and infected with a lethal dose of influenza A virus. The mice showed a variety of immune responses that indicated protection against flu, and also developed immunity against other virus subtypes. Mice that received heat-killed lactic acid bacteria (DK128) prior to infection had about 18 times less influenza virus in their lungs compared to control mice. All survived.
All of the control mice, which were not pretreated with DK128 but were infected with the same lethal dose of virus, died.
"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 lead author Dr. Sang-Moo Kang.
"Our results are highly significant because mice pretreated with DK128 had 100 percent survival and prevention of weight loss," Kang said. "This strain of lactic acid bacteria also equipped mice with cross-protective immunity against secondary lethal infection with influenza virus.
The study's results were published in the journal Scientific Reports.
In addition to being found in probiotics, lactic acid bacteria are also used to turn milk into cheese or yogurt and cabbage into sauerkraut. Previous studies found that some strains of lactic acid bacteria provide partial protection against bacterial infectious diseases, such as Streptococcus pneumoniae, as well as cold and influenza viruses.
"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," Kang said.
The goal of many scientists is to develop a flu vaccine that will provide a lifetime of protection with a single shot, and Australian scientists may have found the key. The answer may be special flu-fighting cells in our noses that can act as a "nasal border patrol" to prevent the virus from ever reaching our lungs.
Previous research has centered on white blood cells called resident memory CD8 T cells or Trms, that are found in the lung and protect against different strains of flu. However, they die too quickly to help in creating a vaccine.
The Australian scientists found Trms in the nose that, unlike those in the lungs, could live for a very long time. Since flu viruses enter mainly through the nose, researchers believe that they can develop a vaccine that will stimulate the Trms in the nose to stop the virus before it enters the respiratory system. The vaccine would provide protection from all flu viruses, including pandemic strains.
https://www.newsmax.com/health/health-news/probiotics-protect-flu-influenza/2017/12/14/id/831796/
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. Researchers have identified 18 different HA and 11 different NA subtype molecules.
This means that the two subtypes can combine to form many variations of flu, which changes from season to season, and is why it is important to find ways to provide protection, regardless of the virus strain.
The new 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 were pretreated with DK128 intranasally and infected with a lethal dose of influenza A virus. The mice showed a variety of immune responses that indicated protection against flu, and also developed immunity against other virus subtypes. Mice that received heat-killed lactic acid bacteria (DK128) prior to infection had about 18 times less influenza virus in their lungs compared to control mice. All survived.
All of the control mice, which were not pretreated with DK128 but were infected with the same lethal dose of virus, died.
"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 lead author Dr. Sang-Moo Kang.
"Our results are highly significant because mice pretreated with DK128 had 100 percent survival and prevention of weight loss," Kang said. "This strain of lactic acid bacteria also equipped mice with cross-protective immunity against secondary lethal infection with influenza virus.
The study's results were published in the journal Scientific Reports.
In addition to being found in probiotics, lactic acid bacteria are also used to turn milk into cheese or yogurt and cabbage into sauerkraut. Previous studies found that some strains of lactic acid bacteria provide partial protection against bacterial infectious diseases, such as Streptococcus pneumoniae, as well as cold and influenza viruses.
"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," Kang said.
The goal of many scientists is to develop a flu vaccine that will provide a lifetime of protection with a single shot, and Australian scientists may have found the key. The answer may be special flu-fighting cells in our noses that can act as a "nasal border patrol" to prevent the virus from ever reaching our lungs.
Previous research has centered on white blood cells called resident memory CD8 T cells or Trms, that are found in the lung and protect against different strains of flu. However, they die too quickly to help in creating a vaccine.
The Australian scientists found Trms in the nose that, unlike those in the lungs, could live for a very long time. Since flu viruses enter mainly through the nose, researchers believe that they can develop a vaccine that will stimulate the Trms in the nose to stop the virus before it enters the respiratory system. The vaccine would provide protection from all flu viruses, including pandemic strains.
https://www.newsmax.com/health/health-news/probiotics-protect-flu-influenza/2017/12/14/id/831796/
