How does the immune defense work with a cold?

Cold sickness icon image

(picture: stock.adobe.com, sebra)

Every day the body is exposed to external attacks by viruses, bacteria, fungi and other foreign substances. Then the immune system comes into play: It has the task of fending off these pathogens and protecting the body. But how does the immune defense work in case of a cold?

Cold defense: what is a cold anyway?

In order to understand how the immune defense of a cold works, the first question that arises is what a cold actually is: inflammation of the upper respiratory tract, usually due to an infection with cold viruses.

Typical symptoms include:

  • Sore throat
  • to cough
  • sniff
  • Shivering
  • Exhaustion
  • Headache and body aches

The Difference Between Cold and Flu is mainly due to the fact that normally there is no fever with a cold. The course is usually uncomplicated and the disease is usually over in about ten days.[i]

Components and function of the immune system

The immune system is one of the most complex systems in the body. It is not located in a specific place, but rather forms a network of cells, tissues and organs.

Its job is to protect the body from external pathogens and foreign substances. This also includes fighting a cold. It is also responsible for wound healing.

Two levels of the immune system

The immune system consists of two levels:

The unspecific defense system is innate. In babies it has not yet fully developed, but it can already protect against some pathogens. It mainly includes external barriers such as skin, mucous membranes, tear fluid, stomach acid, saliva and urine. It also includes white blood cells and certain signal substances.

The specific defense system only develops in the course of life. Its functionality is based on the fact that certain cells “remember” pathogens with which they have already had contact. If this pathogen attacks the body again, the immune system can act faster and more effectively.

Components of the immune system

A number of helpers are involved in the immune system. These include, for example, organs and tissues such as bone marrow, thymus, lymph nodes and spleen.

The most important immune cells are:

  • B lymphocytes: They form specific antibodies that bind to bacteria, viruses and other foreign substances.
  • T lymphocytes: They attack the antigens of the pathogen and the affected body’s own cells.
  • T helper cells: They are a subgroup of T lymphocytes and are solely responsible for recognizing antigens.
  • Dendritic cells: They have a monitoring function. Thanks to their specific shape, they can capture pathogens and pass them on to T cells in the lymph nodes.
  • Macrophages: The so-called giant phobia cells enclose foreign cells and dissolve them inside.
  • Regulatory T cells: They are responsible for the balance in the immune system and stop the defense after recovery so that the body does not attack its own cells.
  • NK cells: The so-called killer cells track down cells infected by the pathogen and kill them.

The antibodies produced by the B cells are an important part of the immune system. They bind to the antigens of the pathogens and mark the attacking cells. So other immune cells can eventually destroy them.

How can the immune system fight a cold?

The triggers are so-called cold viruses (for example rhino and adenoviruses). While these are less aggressive than the flu (influenza) virus, there are more than 200 types.[ii] For this reason there is no vaccination against colds.

Immune defense against a cold: how does it work?

When infected, the pathogens first hit the mucous membrane of the airways. Normally, the cilia located there transport foreign substances into the throat, where they are swallowed and destroyed by gastric juice. This self-cleaning of the airways works worse in winter because of the cold and dry heating air – therefore the cold season is always in the cold season.

The following happens when fighting colds:

  • An initial unspecific defense reaction of the body causes local inflammation of the throat and pharynx.
  • Then the specific immune system kicks in: antigens on the surface of the pathogen attract phagocytes, which surround it and decompose inside.
  • In addition, lymphocytes form antibodies, Y-shaped arms, which bind perfectly to the antigens of the viruses and can transport them to the phagocytes.

After a successful defense, most of the lymphocytes self-destruct. Normally, however, some remain as memory cells. They save the identifying features of the pathogen and the body can fight the virus faster if it attacks again. However, this does not work with a cold. This is because the cold viruses deceive the body: They send out a false messenger substance and thus prevent the formation of specific antibodies. Therefore, immunity to colds is not possible.

How can the immune system be strengthened?

As a rule, the immune system works well on its own. But there are a number of tips with which we can support and strengthen it:

  • healthy eating
  • Refrain from alcohol and tobacco
  • adequate sleep
  • drink a lot
  • regular exercise in the fresh air
  • avoid stress
  • wash hands regularly and thoroughly
  • ventilate regularly

Sunbathing can also have a strengthening effect on the immune system: the body produces vitamin D, which supports the immune system.

[i] Professional Association of Pediatricians e. V .: Cold (flu-like infection). Url: https://www.kinderaerzte-im-netz.de/krankheiten/erkaeltung-grippaler-infekt/ (01/13/2021).

[ii] Professional Association of Pediatricians e. V .: Cold. Url: https://www.kinderaerzte-im-netz.de/krankheiten/erkaeltung-grippaler-infekt/ (01/14/2021).

January 18, 2021

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