BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: ImmuneSystem

Vampires and COVID-19? They may have something in common; and spoiler, it has nothing to do with bats

Researchers from Trinity College Dublin and the University of Edinburgh think they may have found a new weakness of COVID-19; sunlight! More specifically,  ambient ultraviolet B (UVB) radiation which provides the body with vitamin D. The researchers knew of previous studies of the susceptibility of those with vitamin D deficiency to not only receiving the virus, but also experiencing the entirety of it’s wrath. However, in most cases measures weren’t taken to rule out the possibility of confounding factors (other conditions that can cause both vulnerability to COVID-19 and vitamin D deficiency). In order to jump this hurdle, the researchers used “genetically predicted” vitamin D levels.

Sunny day

With this averaged sample, the researchers used an analytical process called Mendelian Randomization . The process allowed them to test correlations between Vitamin D levels and COVID-19. This process had been attempted in past studies, and the researchers results did not contradict previous conclusions; a link between vitamin D levels and COVID-19 was not evident. However, the researchers of Trinity and Edinburgh wanted to test the effects of UVB radiation. UVB radiation from sunshine is the most important supplier of vitamin D for many, yet it was not included in previous studies.

 

Studying almost half a million people from the UK, the researchers compared the genetically predicted levels effect versus UVB predicted levels effect on COVID-19 infection. “researchers found that correlation with measured vitamin D concentration in the circulation was three-fold stronger for UVB-predicted vitamin D level, compared to genetically-predicted” (Trinity College Dublin). The researchers found a correlation of high strength in the negative between UVB radiation and hospitalization and death due to COVID-19 as well.

While the researchers admit that the sample size of the study is not quite large enough to be entirely conclusive, especially considering the surprising deviation from the results of the genetically predicted study, they are optimistic that with time their theory will prove significant. The odds are with them as vitamin D has been found to be a benefactor of the immune system in general. A fact demonstrated by the presence of vitamin D receptor on both B and T cells, and the trend of higher susceptibility to infection of those with lesser amounts of vitamin D.

 

COVID-19 May Induces Cell That Produce Antibodies for Life

Once in our body, SARS-CoV-2, the virus that causes COVID-19, forces the body’s innate immune system to activate. However, the innate immune system response typically is deemed unsuccessful due to the complexities of the virus’s structural components, which then paves way for the body’s adaptive immune response to initiate. As we learned in Biology, adaptive immune response begins with a macrophage engulfing SARS-CoV-2 through phagocytosis. Then, the MHC proteins present on the macrophages, white blood cells that surround and kills microorganisms, remove dead cells, and stimulates the action of other immune system cells,” display the antigen on the surface, creating a ‘wanted’ poster for the immune system (Cancer.Gov). We also learned that eventually, a T-Helped cell comes along and binds to the displayed antigen, which activates the T-Helper cell which fosters the secretion of interleukin, a cytokine. Finally, both B and T cells are stimulated, which then begin the process of fighting off the virus, along with preventing reinfection. One of the cells that assists in the preventing reinfection are B-Plasma Cells, which are, “antibody-producing immune cells [that] rapidly multiply and circulate in the blood, driving antibody levels sky-high”(WashU School of Medicine).

Tingible body macrophageOne crucial step in determining a person’s ability to fight reinfection is testing to see if antibody secretion has either occurred or is currently occurring. While typical blood samples will suffice, “the key to figuring out whether COVID-19 leads to long-lasting antibody protection, Ellebedy [ PhD, and associate professor of pathology & immunology] realized, lies in the bone marrow”(WashU School of Medicine). The B Lymphocytes, which initiate a humoral response, mature in the bone marrow, and so, to determine the prevalence of antibody secreting cells, bone marrow samples must be received from past COVID-19 patients. To determine if antibody production increases after the body completes its fight against, Ellebedy collected blood samples and “As expected, antibody levels in the blood of the COVID-19 participants dropped quickly in the first few months after infection and then mostly leveled off, with some antibodies detectable even 11 months after infection” (WashU School of Medicine). However, people who exhibited mild cases of COVID-19, meaning that their body removed the virus after two to three weeks, antibodies continue to secrete antibodies, and will continue for an indefinite time period.

Covid-19 San Salvatore 09One problem introduced was rooted in the mainstream media, which spread a misinterpretation of data, being that “antibodies wane quickly after infection with the virus that causes COVID-19” (WashU School of Medicine). Ellebedy believes that this is a major misinterpretation of data, and actually means that antibody production is continuing inside of the bone marrow. Typically, antibody production plateaus after a certain period of time preceding infection, yet these numbers don’t go to zero.

Ellebedy concludes that this result is highly promising, especially for people who experienced a more severe infection from SARS-CoV-2, because an increased amount of circulating virus cells typically leads to a stronger immune response due to the body being required to secrete more antibody cells. Although she believes that more studies need to undergo in people who experienced moderate to severe infections, and show if they also have the same everlasting antibody production.

 

 

 

 

 

 

Can a Plant Based Diet Protect You from Covid?

The Covid-19 pandemic has affected and devastated millions of people all over the world over the past two years. Even after religiously wearing masks and more than half of the world’s population getting vaccinated, we still need to live in caution of getting infected with this virus every day. Although Covid-19 is known to be one of the most contagious viruses to exist, it has been discovered in a recent article that maintaining a healthier lifestyle and diet will decrease your chances of getting infected as well as minimize any symptoms if you do happen to get infected. We all know that overall if you are able to maintain healthy habits, your immune system will be stronger and therefore, able to fight off infection more effortlessly, but applying this same idea to Covid-19 may help us escape this pandemic sooner than expected. 

Since data on this theory was lacking, Dr. Jordi Merino and his colleagues conducted an experiment to gather more evidence. 592,571 participants were selected and began by completing a questionnaire assessing their dietary habits before the pandemic. Participants who had healthy eating habits had a 9% lower chance of contracting the virus and a 41% lower chance of developing severe Covid-19. Merino concluded that in addition to wearing masks and getting vaccinated, we should all try to maintain healthy, plant-based diets to fight against Covid.

Healthy non-sugar diet

In addition to the health benefits of having a plant-based diet, it improves your immune system because of the antioxidants, vitamins, minerals, and phytochemicals found in plants. These components work to keep your cells healthy and working at their fullest potential to fight off infection. They resolve inflammation in the body by neutralizing toxins, processed foods, bacteria, and viruses. With all the benefits, why wouldn’t you go plant-based?

It may sound pretty simple: if I go plant-based and I won’t get sick, right? Not exactly. It is found that the risk of  Covid-19 is greater in areas of high socioeconomic deprivation. This is because the people who inhabit these areas are unable to maintain the same lifestyle as people who are more fortunate. Plant-based diets and healthier lifestyles are generally more costly, causing them to be less accessible to everyone. This is one of the main reasons that Covid is still a great risk to our society. For more information about a plant-based diet decreasing Covid risks, click here.

In AP Biology we learned how your immune system works to fight against any invading viruses in your body. When you are contracting a virus, the pathogen first needs to pass through your barrier defenses. These are the natural defenses with which you are born. For example, they include mucus, skin, stomach acidity, blood and lymph proteins, etc.. If you are an unhealthy person and these defenses aren’t working properly, you are much more susceptible to disease and then need to rely on your internal defenses.

Primary immune response 1

This diagram shows how the humoral and cell-mediated responses work in the body to fight off disease.  When a pathogen enters the body, your immune system will attack either the pathogen itself when loose in your bloodstream and bone marrow or attack and kill an entire infected cell. Keeping your immune system strong by eating right and frequent exercise will also ensure that these defenses will fight off disease quickly and form antibodies to prevent future reinfection. A healthy person is by no means immune to a virus, but they will experience fewer symptoms as well as recover faster because their immune system works faster. This means that fewer cells will become infected and the virus will have less time to replicate and multiply.

As someone who runs track and cross country, it is very important to me to keep my diet as healthy as possible. Though a plant-based diet doesn’t suit my lifestyle best, I do make healthy food choices as often as I can to properly fuel myself and to ensure I don’t get sick. This seems to be working well for me as I am still yet to get infected with Covid-19 or show any symptoms.

The Unknown Disinfecting Protein

When our body is invaded by a virus, it will send its army to fight it, this army is known as the Immune System. The Immune System uses white blood cells to do most of the pathogen killing work, sending white blood cells in waves. The Immune System records the pathogens signature features and creates antibodies to fight the particular invader. But in some cases, the Immune System’s antibodies “are less effective against pathogens that have already penetrated the interior of the cells.” When bacteria microbes get past the Immune System and get to the cytoplasm, the bacteria will replicate. This is where a protein comes and dissolves the bacteria in the cell.

A less known family of proteins called the Apolipoprotein can actually dissolve bacteria that is in the cytoplasm. Researchers at Howard Hughes Medical Institute at Yale discovered the APOL3 in particular had the ability of dissolving a bacteria. An experiment with un-immune cells, cells that are not protected by Immune System, and the bacteria, Salmonella. Salmonella has a double membrane, similar to mitochondria and chloroplasts, making it very hard for cells to kill it. The APOL3 protein, however, “binds to and destroys the inner membrane of virulent bacteria like salmonella and kills them.” APOL3 only removes the inner layer, with the help of an immune protein called GBP1, GBP1 can remove the outer layer and set up APOL3 for the final shot. The way APOL3 dissolves bacteria is by shooting or surrounding the bacteria with APOL3 molecules and it just goes away. This is probably why researchers called it the detergent. The way APOL3 does this scientifically is by possessing “parts attracted to water and parts drawn to fats.” Since membranes are mostly made of lipids, the bacteria is a sphere of lipids and inside are its organelles. The APOL3 binds to and destroys the lipid membrane, releasing all the cytoplasm organelles out and killing the bacteria. APOL3’s method of dissolving must dissolve some other parts of the cell right? Well, APOL3 actually has a selective target, targeting bacteria lipids and not attacking cholesterol.  As we learned in class, cholesterol is a lipid which is part of the plasma membrane as well as the building block of other steroids. Because APOL3 cannot target cholesterol, our human cells are safe.

Salmonella

“Salmonella” by National Institutes of Health (NIH) is licensed under CC BY-NC 2.0

 APOL3 is a very diverse protein and allows it to be around the whole body. Humans have a very strong defense system, having the Immune System as well as detergent like proteins around the body, lipid based bacteria will have a hard time in our cells.

 

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