The Guards of Our Body

The Guards of Our Body

Mingzhu Victoria Huang

In a time amidst the Covid-19 pandemic, it has become increasingly apparent how important our body’s defense mechanism is and what it does when facing a viral attack. We are made of cells; single-living immune-cells gives rise to a complicated defense barrier against invaders, and one of our most important organs is the immune system which consists of different immune cells and antibodies that produce from cells. Being the keystone contributor of the immune system, an intricate layer of lymphocytes has provided life the ability to evolve and create a defense system for millions of years. One of the most important lymphocytes, called Natural Killer cells (NK cells), have the ability to destroy and damage cells in which its surfaces are changed from gene mutations or infected by bacteria, viruses, etc.

There are more than ten different immune cells present in our blood stream including T-cells, B-cells, macrophages, δβT-cells, DC and NK cells, etc. All of them play a critical role in the defense against foreign invasions through using a variety of different procedures in the body. As the pathogen encounters surveillance cells when our body is infected by foreign invaders, NK cells immediately migrate and kill the pathogen infected cells or mutated cells. The NK cells specifically attack the invaded cells without using help from other cells and transduction materials while the dendritic cells (DC) can be loaded with foreign antigens even if the bacterial, viral infected, or gene mutated cells produce new antigens. It can load a large number of new antigens during the early stage of DC development.

On the other hand, the captured new antigens by DC cells are presented to the surface of the T-cells for them to kill pathogenic infected or mutated cells such as cancer cells. The T-cells are classified as CD4+T cells and CD8+T cells. CD4+T cells are called helper T lymphocyte cells which assists in producing an immune response whereas CD8+T cells are the cytotoxic T cells that induce cell death through apoptosis or lysis. CD8+T cells can directly kill the pathogenic infected or mutated cells by secreting two types of preformed cytotoxic protein: granzymes and the glycoprotein perforin. They have a very extensive memory against specific antigen features for long periods of time.

With the help from our immune system and cells, we are able to defend ourselves against foreign attacks from different bacteria and viruses. Nowadays, maintaining a healthy immune system is becoming more and more important especially with the increasing number of emerging viruses.