Immunity 3 MIN READ 67 VIEWS April 18, 2022

A Complete Guide on T-Cell Immunity

Written By HealthKart
Medically Reviewed By Dr. Aarti Nehra

T-cell immunity

T-cells are essential parts of the immunity system that help fight germs, diseases, and other factors that are harmful to the body. They originate from the bone marrow and are essential for the survival of the human body. They mature in the thymus after they originate from the bone marrow. Further, T-cells have very complicated functioning and are the main reason behind cell-mediated immunity. T-cells differentiate into helper, regulatory, or cytotoxic T-cells or become memory T-cells. Notably, memory T-cells remember the germ (viruses, bacteria) and help protect the body from diseases it has once contacted before like chickenpox. Recently, T-cell immunity and cell-mediated immune response have been under the radar after the onset of the pandemic. 

Functions of T-cells

As discussed above, the most common function of T-cells is to fight off infection-causing germs that may otherwise lead to problems for the body. T-cell immunity also helps in protecting the body from some specific foreign particles that other organs are unable to fight off. Their response is also important in countering allergens, tumours, and specific foreign particles. Besides, T-cells are responsible for maintaining an equilibrium in the immune system

Over the course of human life, T-cells switch roles. And, this makes them one of the most developed functions of the human body. In infancy, T-cells develop immunity against common allergens and pathogens. As the body grows, memory T-cells retain these immune memories and use them whenever the body encounters the same pathogen or allergen. An interesting fact is that without memory T-cells, the human body could die from something as simple as a common cold. 

In older age, their function changes completely and T-cells focus just on maintaining homeostasis and regulating the immune system. It is only triggered when a known and recognized pathogen enters the body and the T-cells get out to fight it off. In old age, the functionality of T-cells decreases and that causes pathogens to attack. This is one of the reasons people die of decreased immunity in old age. 

How do T-cells Work? 

The working of T-cells to form cell-mediated immunity is a very interesting process. T-cells originate in the bone marrow and mature in the thymus. They are only activated after they find a suitable antigen.

 Helper T-cells and cytotoxic T-cells (two of the types of T-cells) help with immunity. While cytotoxic T cells kill infected cells, Helper Tcells need a certain kind of a secondary signal from other cells (macrophages, B cells, or cytotoxic T cells) to activate fully. Only after this can they be effective towards a specific threat.

In short, T-cells require and rely on a lot of other compounds and cells of the body to function well. 

Role of T-cells in COVID-19 Pandemic 

T-cells and T-cell immunity have been a constant matter of discussion since the start of the pandemic. This is largely due to the fact that COVID-19 is a viral disorder unlike many which WBC and T-cell immunity fight off in the body. So, what is the exact relation of T-cell immunity to COVID-19? 

T-cells are crucial to a patient of COVID-19 who is recovering. Boosting T-cells is an excellent way for the body to combat the viral infection. Initially, studies showed that boosting T-cells is the surefire way of getting rid of COVID-19. However, recent studies and the mutations in the virus have changed the scenario considerably. In fact, a recent study shows that patients who have suffered more diseases are less prone to the severity of COVID-19. This is exactly the opposite of what scientists initially recorded. More research is needed in this particular field. 


T-cells are crucial in keeping you safe from diseases. And, to help out your T-cells, you should try to live a healthy lifestyle. Consuming nutritious food; regular exercising; and cutting down on fried foods, smoking, and alcohol can do wonders for your T-Cell immunity.

Read these next