Influence of previous colds in the course of COVID-19
A previous infection with Erkältungsvviren influenced the Severity of the gradient of Covid-19? New study results indicate that such a protective effect, since in the case of a Vorinfektion formed by immune cells also act against the new Coronavirus, SARS-CoV-2.
In a recent study at the Charité – Universitätsmedizin Berlin, a possible connection between the previous colds, and a protective effect against a severe course of COVID-19 was detected. The results were published in the English journal “Nature”.
How to protect the body against the Coronavirus?
The human immune system protects itself by means of a special multi-stage defence strategy against pathogens such as the Coronavirus SARS-CoV-2. On the one hand, specific antibodies are formed against specific surface structures of the Virus, on the other hand, the immune system uses various cells to ward off pathogens, for example, several types of T-cells. These respond to parts of the surface proteins of the Virus, what helps to coordinate the immune response and antibody production, explain the researchers.
What is the role T-cells play?
Affect the presence of specific T-cells could, in some people the course of COVID-19 critical. This was shown in the investigation of the T-helper cells from the blood of 18 people with COVID-19 and 68 healthy Participants. Approximately one-third of the studied Participants the research group found the appropriate helper T cells.
How was established the study?
These immune cells, called CD4 T-cells were taken for the study with various sections of the Spike Protein of SARS-CoV-2 in connection. The T-helper cells from the blood of most people with COVID-19 responded to the Protein parts of the corona virus, reports the researchers.
The immune system of healthy people detected Virus
The research group was surprised by the idea that the T-reacted cells of some healthy Participants also on the viral protein pieces. About one-third of healthy Participating in T-helper cells were present, which fragments of SARS-CoV-2 identified. With other words: There were actually people, which never had contact to the new Coronavirus, but whose immune system recognized despite this, the Virus.
A possible origin of the response to the Coronavirus
The research group found a possible reason for the above-mentioned reaction. T-cells of people with COVID-19 not responded to almost all of the components of the Spike Protein, however, this was when T-cells from healthy Participants in the case. T-cells were activated only partial structures of the Protein, which is evolutionarily older and also with other, closely related coronaviruses (SARS-CoV or four well-known cold-corona virus) occur.
Prior cold leads to protective effect?
This finding suggests that T-helper cells from healthy humans to SARS-CoV-react 2 because you had to put in the past, with native cold-corona virus apart. A well-known property of T-helper cells is that they are not activated exclusively by the appropriate agents, they can also be of similar pathogens activated.
What are memory helper T-cells?
Reaction tests with protein parts of the popular cold-corona virus showed that T-helper cells from healthy subjects heavily on these speeches. This lies close to the fact that about a third of the healthy Participants had lived in their past to a cold, which was caused by a harmless common cold coronaviruses. After such an infection-called T-helper appear in the body-remain-memory cells, seem to react later to the new Coronavirus.
Cold weakens symptoms of COVID-19?
The researchers are of the opinion that cross-reactive T-helper cells could have a protective effect, for example, by the fact that faster by the body, antibodies are formed against the novel Virus. This presumption should apply, could weaken a short time ago by made Coronavirus-common cold symptoms of COVID-19 probably.
Is triggered a faulty response of the immune system?
It would, however, also possible that these cross-reactive immunity aggravates the course of COVID-19, report the researchers. By the ability of immune cells or antibodies to a Virus does not dock, even though they fit perfectly on the structure, can also be a faulty immune system response triggered. As a result, the body may turn on its own defense, the Virus, and the pathogens continue to multiply, and it comes at the same time a response to an exaggerated immune.
Further research is needed
Which of the two above-mentioned theories is true, should now be in a follow-up study clarified. In such an investigation, particularly of people should be involved, which have developed through the common cold virus may be a certain degree of immunity to SARS-CoV-2, because they have in the past made frequent colds due to, confess to the researchers. This could then have resulted in these individuals, cross-reactive T-helper cells contribute to a special protection. At the same time, the research group Corona plans to accompany groups at risk medically. This could help the course of COVID-19 both before and after SARS-CoV-2 infection better predict. (as)