BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: flu

Gut Microbes Help to Advance Flu Vaccines

Beneficial Gut Bacteria

This September, a potentially monumental study was published in the scientific journal, Cell, reporting that researchers have confirmed that microbes present in the gut can change, lower, or jumpstart our immune response.  Previously research has only been done with other mammals such as mice, and this was the first study that linked the results to human subjects. Since most previous trials were conducted on other animals, researchers such as Dan Littman who studies microbiota at NYU School Of Medicine, emphasized there are likely to be large differences in the results for humans versus other animals.   

Specifically, researchers found that people who have not received a flu shot or had the flu within the past 3 years and then were administered broad spectrum antibiotics, produced lower levels of antibodies to the influenza virus. Those subjects who did not receive the antibiotics produced more antibodies to the flu virus. This publication is so noteworthy because previously so little actual human clinical trials were performed to understand the role of the human gut microbiome and its relationship to the strength of our immune response.  

Previous research on how the flu vaccine works and its varying efficiency among many people has been done.  In 2011, Bali Pulendran, an immunologist at Stanford University, found that increased activity in the gene receptor that recognizes the bacterial protein flagellin, the core part flagella, seemed to stand out as the one major change among how well the flu shot was working in varying groups of people.  This underscores the connection between the immune system’s recognition of bacteria (especially gut microbes) and  how well people may respond to the flu vaccine.  

In 2014, this research was followed by gene knockouts being given to mice for the receptor for bacterial flagellin in the flu shot.  The results showed that the mice who received the knockouts made were antibodies than the control mice in the trial.  The researchers suspected this reduction was controlled by the absence or presence of gut microbes and their ability to sense flagellin.  To confirm this, researchers followed up with separate trial in which mice’s microbiota were reduced by the administration of antibiotics before receiving the flu vaccine and control mice who did not receive the antibiotics so their microbiomes remained present.  The results again showed a link that gut microbiota play a role in levels of antibodies produced against their flu shot.  Because of these results, it seemed obvious to test the same situation with humans. 

The current study did just that and was designed as a Phase 1 clinical trial to determine if gut microbes are connected to the efficiency of flu vaccine immunity.   11 adults received broad spectrum antibiotics for 5 days and 11 served as the control and did not receive antibodies.  All subjects receive the influenza vaccine on day 4. The people who received the antibiotics had reduced levels of gut microbes.  However, no major difference was observed in response to the vaccine. These results prompted researchers to dig deeper and they next investigated people who had not had the flu shot or suffered from the flu virus within the last 3 years.  They wanted subjects that would be relatively clear of flu antibodies to begin with. They repeat a very similar study with 11 people, 5 receiving the antibiotics and 6 serving as controls. Everyone got the flu vaccine, but this time the results showed a marked difference in vaccine induced immunity.  Subjects who received antibiotics and had fewer microbes presents, made far fewer flu-specific antibodies.   

This research is very promising not only in the field of flu vaccination, but could reveal that changes to microbiota can have profound impacts on future vaccine development for a variety of pathogens.  Because the results were so tiring, Pulendran is continuing to research deeper into the relationship between gut bacteria and vaccines, for viruses that may affect us in the future. This holds promise for development of vaccines for a wide range of pathogens that attack the human race.  

 

Does Exposure to Toxins In the Environment Affect One’s Offspring’s Immune System?

A study has recently surfaced stating that maternal exposure to industrial pollution may harm the immune system of one’s offspring and that this impairment is then passed from generation to generation, resulting in weak body defenses against viruses.

Paige Lawrence, Ph.D., with the University of Rochester Medical Center’s Department of Environmental Medicine, led the study and conducted research in mice, which have similar immune system functions as humans. Previously, studies have shown that exposure to toxins in the environment can have effects on the respiratory, reproductive, and nervous system function among generations; however, Lawrence’s research is the first study to declare that the immune system is also impacted.

“The old adage ‘you are what you eat’ is a touchstone for many aspects of human health,” said Lawrence. “But in terms of the body’s ability to fights off infections, this study suggests that, to a certain extent, you may also be what your great-grandmother ate.”

“When you are infected or receive a flu vaccine, the immune system ramps up production of specific kinds of white blood cells in response,” said Lawrence. “The larger the response, the larger the army of white blood cells, enhancing the ability of the body to successfully fight off an infection. Having a smaller size army — which we see across multiple generations of mice in this study — means that you’re at risk for not fighting the infection as effectively.”

In the study, researchers exposed pregnant mice to environmentally relevant levels of a chemical called dioxin, which is a common by-product of industrial production and wast incineration, and is also found in some consumer products. These chemicals eventually are consumed by humans as a result of them getting into the food system, mainly found in animal-based food products.

The scientists found the production and function of the mice’s white blood cells was impaired after being infected with the influenza A virus. Researchers observed the immune response in the offspring of the mice whose mothers were exposed to dioxin. Additionally, the immune response was also found in the following generations, as fas as the great-grandchildren (or great- grandmice). It was also found that this immune response was greater in female mice.  This discovery now allows researchers to have more information and evidence to be able to more accurately create a claim about this theory.

As a result of the study, researchers were able to state that the exposure to dioxin alters the transcription of genetic instructions. According to the researchers, the environmental exposure to pollutants does not trigger a genetic mutation. Instead, ones cellular machinery is changed and the immune response is passed down generation to generation. This discovery explains information that was originally unexplainable. It is obviously difficult to just avoid how much toxins you are exposed to in the environment, but it is definitely interesting to see the extent of the immune responses in subsequent generations. We can only hope that this new information, and further discoveries, help people adjust what they release into this world that results in these harmful toxins humans are exposed to, and their offsprings.

 

 

 

Stop! Don’t Smell the Roses!

800px-SneezeDuring the flu season, we all try to be a little more vigilant when it comes to germs. Even as a self-proclaimed “germaphobe,” I was not as lucky to escape the evil grasp of the disease. Aside from recognizing  the obvious perpetrators, who include those who refuse to cover their mouths, people who breathe just a little too close to me, and  grimy freshmen, I wanted to find out a little more about the  origin of diseases.

 An interesting area of research regarding the topic is being pioneered by Scott McArt and Lynn Adler of the University of Massachusetts Amherst. They are investigating how great a role flowers play in the transmission of diseases. Around 190 studies having to do with flowers and diseases they pass on have been dated back to the lat 1940’s. This research is important because it can “help efforts to control economically devastating pollinator-vectored plant pathogens.” Still, this topic is very new and not as conclusive as many would think. Despite this fact, “eight major groups of animal pathogens that are potentially transmitted at flowers” (by bees and other pollinators) have been discovered. It is unknown whether pathogens are transmitted via the chemical or physical traits of flowers. 

The main goal of the study was to attention to the need to further explore the relationship between flowers, their pollinators and diseases, as many people have expressed concern for “the pollinator declines caused in part by pathogens.” Do you agree that this is an area worth researching?

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