People May Have a Pre-Existing Immune Response to COVID-19 Thanks to Common Colds

AHA Publisher — Wed, 12 Aug 2020 07:00:35 +0000

Angela Betsaida B. Laguipo, BSN via News-Medical Net – A new study shows that some people have immune responses against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19, thanks to how the body reacted the last time it caught a cold. This means that even if a person has not been exposed to the novel coronavirus, the body has a memory of it and can trigger an immune response to fight the infection. Common Colds The researchers from the La Jolla Institute for Immunology (LJI) have found that previous infections with common cold viruses KHU1, OC43, NL63, and 229E can train the immune system to detect and recognize SARS-CoV-2. Published in the journal Science, the study highlights the power of the immune system to protect against infection and illness. The team revealed that immune cells, called T cells, which can spot common cold coronaviruses, can recognize the specific sites on the virus, such as the “spike” protein. This type of protein is used by the virus to bind and invade healthy human cells. The Study To arrive at their findings, the team used human blood samples before SARS-CoV-2 was discovered in December 2019. From there, they mapped 142 T cell epitopes across the SARS-CoV-2 genome to help facilitate precise interrogation of the SARS-CoV-2-specific CD4+ T cell repertoire. “We demonstrate a range of pre-existing memory CD4+ T cells that are cross-reactive with comparable affinity to SARS-CoV-2 and the common cold coronaviruses HCoV-OC43, HCoV-229E, HCoV-NL63, or HCoV-HKU1. Thus, variegated T cell memory to coronaviruses that cause the common cold may underlie at least some of the extensive heterogeneity observed in COVID-19 disease,” the researchers concluded in the study. The team also found that 40 to 60 percent of people who were never exposed to SARS-CoV-2 had T cells that reacted to the virus. The immune systems of these people recognized fragments of the virus it had never seen before, which may explain why some develop only mild symptoms and why some are asymptomatic. Despite the promising results, the researchers said that further research and data collection are still needed to arrive at a more conclusive result. “We have now proven that, in some people, pre-existing T cell memory against common cold coronaviruses can cross-recognize SARS-CoV-2, down to the exact molecular structures. This could help explain why some people show milder symptoms of the disease while others get severely sick,” Daniela Weiskopf, LJI Research Assistant Professor, said. Meanwhile, Professor Alessandro Sette, study co-author, said that immune reactivity might translate to various levels of protection. In people with a robust T cell response, they have the chance to mount a faster and more robust response against the virus that causes COVID-19. Global Situation of COVID-19 Understanding the mechanism of SARS-CoV-2 can help scientists develop treatments and vaccines against the coronavirus pandemic. These studies can help hasten the discovery of therapeutics to contain the spread of the deadly virus that has killed more than 731,000. The coronavirus pandemic has now reached 188 countries and territories, infecting 19.86 million people. The United States remains as the country with the highest number of confirmed cases, reporting more than 5 million cases and more than 162,000 deaths. Brazil and India report high transmission rates, with more than 3 million and 2.2 million confirmed cases, respectively. Of these, the official tally has confirmed more than 11.96 million recoveries from SARS-CoV-2 infection. The WHO has said that the new epicenter of the pandemic is in the Americas. South America’s Brazil, Peru, Colombia, and Chile report the high numbers of confirmed cases. This article has been modified. To read the original article click here.

The post People May Have a Pre-Existing Immune Response to COVID-19 Thanks to Common Colds appeared first on Amazing Health Advances.

Exposure to Common Cold Coronaviruses Can Teach the Immune System to Recognize SARS-CoV-2

AHA Publisher — Wed, 05 Aug 2020 07:00:24 +0000

La Jolla Institute for Immunology via EurekAlert – Your immune system’s “memory” T cells keep track of the viruses they have seen before. This immune cell memory gives the cells a headstart in recognizing and fighting off repeat invaders. Now, a new study led by scientists at La Jolla Institute for Immunology (LJI) shows that memory helper T cells that recognize common cold coronaviruses also recognize matching sites on SARS-CoV-2, the virus that causes COVID-19. The research, published Aug. 4, 2020 in Science, may explain why some people have milder COVID-19 cases than others–though the researchers emphasize that this is speculation and much more data is needed. “We have now proven that, in some people, pre-existing T cell memory against common cold coronaviruses can cross-recognize SARS-CoV-2, down to the exact molecular structures,” says LJI Research Assistant Professor Daniela Weiskopf, Ph.D., who co-led the new study with LJI Professor Alessandro Sette, Dr. Biol. Sci. “This could help explain why some people show milder symptoms of disease while others get severely sick.” “Immune reactivity may translate to different degrees of protection,” adds Sette. “Having a strong T cell response, or a better T cell response may give you the opportunity to mount a much quicker and stronger response.” The new work builds on a recent Cell paper from the Sette Lab and the lab of LJI Professor Shane Crotty, Ph.D., which showed that 40 to 60 percent of people never exposed to SARS-CoV-2 had T cells that reacted to the virus. Their immune systems recognized fragments of the virus it had never seen before. This finding turned out to be a global phenomenon and was reported in people from the Netherlands, Germany, the United Kingdom and Singapore. Scientists wondered if these T cells came from people who had previously been exposed to common cold coronaviruses–what Sette calls SARS-CoV-2’s “less dangerous cousins.” If so, was exposure to these cold viruses leading to immune memory against SARS-CoV-2? For the new study, the researchers relied on a set of samples collected from study participants who had never been exposed to SARS-CoV-2. They defined the exact sites of the virus that are responsible for the cross-reactive T cell response. Their analysis showed that unexposed individuals can produce a range of memory T cells that are equally reactive against SARS-CoV-2 and four types of common cold coronaviruses. This discovery suggests that fighting off a common cold coronavirus can indeed teach the T cell compartment to recognize some parts of SARS-CoV-2 and provides evidence for the hypothesis that common cold viruses can, in fact, induce cross-reactive T cell memory against SARS-CoV-2. “We knew there was pre-existing reactivity, and this study provides very strong direct molecular evidence that memory T cells can ‘see’ sequences that are very similar between common cold coronaviruses and SARS-CoV-2,” says Sette. Looking closer, the researchers found that while some cross-reactive T cells targeted the SARS-CoV-2’s spike protein, the region of the virus that recognizes and binds to human cells, pre-existing immune memory was also directed to other SARS-CoV-2 proteins. This finding is relevant, Sette explains, since most vaccine candidates target mostly the spike protein. These findings suggest the hypothesis that inclusion of additional SARS-CoV-2 targets might enhance the potential to take advantage of this cross reactivity and could further enhance vaccine potency. To read the original article click here.

The post Exposure to Common Cold Coronaviruses Can Teach the Immune System to Recognize SARS-CoV-2 appeared first on Amazing Health Advances.

cold virus Archives - Amazing Health Advances

People May Have a Pre-Existing Immune Response to COVID-19 Thanks to Common Colds

Exposure to Common Cold Coronaviruses Can Teach the Immune System to Recognize SARS-CoV-2