Antibodies, T-cells, cross-reactivity: The big Corona-immunity-puzzles

Who was once suffering from Covid-19 and the infection has passed, can not develop once again. Or? A lot of Knowledge, there is not in the current pandemic, for which many assumptions. What do we know and what is not.

The emergency relief coordinator of the world health organization (WHO) is skeptical that the new Coronavirus can be eliminated according to the rapid spread around the globe yet. “This Virus can be in the population at home, it may be that it never disappears more and more,” said Michael Ryan in mid-may in Geneva.

Unlike the seasonal flu, there are against Sars-CoV-2, to date, no vaccination. Researchers expect to see a vaccine for at least several months. So far, the Corona-therapy is limited principally to the relieving of the symptoms.

Increasingly, therefore, the question of the possible immunity after surviving Covid-19-disease. It was in the past a few skeptics, most scientists today agree that a person to the disease, at least for a time, immune to Sars-CoV-2. Because in the course of an infection, the immune system of a people is, among other things, antibodies to combat the invading pathogens.

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Reaction of the body: the immune system responds to Sars-CoV-2

When someone infected with Sars-CoV-2, to dock the Virus to so-called ACE2 receptors. It multiplies in the cells of the body, causing the immune system is alerted. First, the innate (nonspecific) responds to immune defense, as soon as you recognize the harmful pathogens. “In this Moment, decides, whether there is any significant disease or not, “explains Thomas Löscher, an Internist and infectious disease Loge from the professional Association of German internists (BDI).

The immune system is strong, it fights the virus successfully and the person Concerned shows only mild or no symptoms of the disease. A weak immune system prevents the virus replication is not sufficient. A serious or even critical progression to pneumonia or multi-organ consequences of failure. The immune system works, the acquired (specific) immune system works to get rid of the disease pathogen again.

The older people become, the less active the innate defense is, your cells respond less strongly. At the same time the immune memory does not work so well. “The immune system in old age, forgetful that we know of vaccinations,” adds Virologist Ulrike Protzer, Institute Director of the Institute for Virology at the Helmholtz Zentrum München. Chronic viral infections may accelerate the age-related changes in the immune system.

At the latest after ten days, the body developed specific Sars-CoV-2-immune system

In healthy or young people but was: “After about a week to ten days, the body develops a specific immune response to the Coronavirus,” describes infections Lodge of the quencher, and has also cared for the first patient in Munich, the way to immunity.

The organism is now so immune cells specifically targeted against this Virus. With these antibodies and the cellular immune response has been learned of the Infected so, with the exciter off. Who has made a Coronavirus infection, therefore, is immune first.

“How long this immunity lasts, and whether it remains a life-long, we don’t know yet,” explains the Professor. It is one of the many still unsolved questions.

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  • Robert-Koch-Institute is about three years of immunity

    The Robert Koch Institute (RKI) writes: “The experiences with other corona virus infections (Sars and Mers) suggest, that the immunity up to three years of stop could be.” The experts see low risk to already Convalescent, to infect again.

    Also, the WHO and a number of experts around the world have since been reported to the word. You can also refer to the experiences with other corona viruses, and are optimistic that a history of infection at least temporarily to a immunity. “There is currently no medically documented case in which someone is declared a second Time to Covid-19 ill”, such as immunologist Thomas Kamradt in an interview with FOCUS Online.

    He, too, is based on the experience from the first Sars epidemic, as well as with a cold corona viruses. You speak according to him, for immunity, the stop at least “a few years”. During this time, Sars-CoV-2 had also no possibility, in the body of the Person to penetrate: “Immune means I’m protected, and I protect the others.”

    Immune to Corona cold? This is what we know so far about the cross-immunities

    Also becoming more common in this context, so-called cross-immunities are mentioned. Researchers around Andreas Thiel from Berlin’s Charité hospital have recently found out that people who never with Sars-CoV-2 came into contact were, an immune response against the Virus could contain.

    The scientists suspect that behind this reaction, a previous infection with a Coronavirus could be stuck, such as in the case of a cold. Such cross-reactivity is not Unusual, however, must now be clarified whether it is good or bad for the patient.  

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    T-cells attack Sars-CoV-2, even though they were never exposed to it

    Researchers from the USA came to similar conclusions: In a recently in the science journal “Cell” published study examined the Infectious disease specialists Alessandro Sette and Shane Crotty from La Jolla, California, Institute for Immunology, such as T-cells from blood samples, which will be between 2015 and 2018 were taken before the current plague to Sars-CoV-2 to respond.

    It turned out that many of the immune cells to attack the pathogen, even though they were never exposed to it. It could be that the affected persons have suffered from a cold that was caused by other, less aggressive corona virus, the conclusion the study authors conclude in this study.

    While is unclear whether the observed cross-reaction of an immune protection bring, but they could explain why Covid-19 some people stronger than others. “Any degree of immunization by a corona virus-induced cross-reaction can modify the global Seuchenzug substantially,” stresses Crotty. “That can take into account the epidemiologists now with their forecasts for the further course of the pandemic.”

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