Helper t cells and killer t cells

• Overview
• Function
• Anatomy
• Conditions and Disorders
• Care

Overview

What are cytotoxic T-cells?

Cytotoxic T-cells are a type of immune cell. They destroy cells infected with viruses. Another name for cytotoxic T-cells is killer T-cells.

Cytotoxic T-cells are one of the three main types of cells developed in your thymus. The thymus is a small gland in the front of your chest. The other types of T-cells include:

• Helper T-cells, which activate other immune cells to fight infections.
• Regulatory T-cells, which suppress other immune cells when needed.

Are cytotoxic T-cells in innate immunity?

No. Cytotoxic T-cells play a role in cell-mediated immunity, a type of adaptive immunity. Innate immunity is the immunity already present in your body. You develop adaptive immunity when you’re exposed to infections or other foreign substances.

What is the difference between cytotoxic T-cells and natural killer cells?

Cytotoxic T-cells attack viruses when activated by an antigen. Natural killer cells don’t need activation to attack harmful cells. Cytotoxic T-cells are part of your adaptive immune response. Natural killer cells are part of your innate immune response.

Function

What is the function of cytotoxic T-cells?

The surface of a cytotoxic T-cell has something called a CD8 receptor. The CD8 receptor interacts with cells called major histocompatibility complex (MHC) Class I molecules to recognize when healthy cells are infected.

When the CD8 receptor recognizes an infected cell, it activates the cytotoxic T-cells. The cytotoxic T-cells create molecules designed to destroy the infection.

How do cytotoxic T-cells and helper T-cells work together?

Helper T-cells aid other cells in the immune response. When they sense an infection, they release cytokines, molecules that send messages to other immune cells. These cytokines help activate cytotoxic T-cells to fight the infection.

Anatomy

Where are cytotoxic T -cells located?

T-cells begin to form first in your bone marrow. They move to your thymus while they’re developing. Your thymus helps your T-cells mature and then circulates them throughout your body.

You have numerous T-cells in your lymphatic system. The highest concentrations of cytotoxic T-cells are in your:

• Bone marrow.
• Intestines.
• Lungs.
• Lymph nodes.
• Spleen.
• Tonsils.

Conditions and Disorders

What are the common conditions and disorders that affect cytotoxic T-cells?

Several types of autoimmune diseases affect your T-cells. Other conditions that affect your T-cells include:

• Acute lymphocytic leukemia, a type of cancer that starts in your blood and bone marrow.
• Adult Hodgkins lymphoma, a disease in which cancer cells start in your lymph system.
• HIV, a virus that attacks your white blood cells and potentially leads to AIDS.
• Job syndrome, a rare immune system disorder that causes repeat infections.
• Thymic aplasia, a condition in which you’re born with an underdeveloped thymus.

Care

What simple lifestyle changes keep my immune system healthy?

Some lifestyle changes can keep your immune system healthy. You may:

• Avoid alcohol or consume it in moderation only.
• Eat a diet filled with fruits, vegetables, whole grains, lean proteins and healthy fats.
• Exercise consistently, incorporating strengthening, flexibility and aerobic activities.
• Sleep at least seven to eight hours nightly.
• Quit smoking and using tobacco products. Talk to your healthcare provider about ways to help kick the habit.
• Wash your hands frequently with soap and water to avoid germs.

A note from Cleveland Clinic

Cytotoxic T-cells are a type of immune cell. They are one of the main types of cells developed in your thymus. Cytotoxic T-cells help fight infections. These cells, along with helper T-cells, are an important part of your adaptive immunity. Several autoimmune diseases and other conditions can affect your T-cells.

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Reviewed by a Cleveland Clinic medical professional.

References

• British Society for Immunology. Helper and Cytotoxic T Cells. (//www.immunology.org/public-information/bitesized-immunology/cells/helper-and-cytotoxic-t-cells) Accessed 7/26/2022.
• Janeway CA Jr, Travers P, Walport M, et al. Immunobiology: The Immune System in Health and Disease. 5th edition. New York: Garland Science; 2001. T cell-mediated cytotoxicity. (//www.ncbi.nlm.nih.gov/books/NBK27101/) Accessed 7/26/2022.
• Kumar BV, Connors T, Farber DL. Human T cell development, localization and function throughout life. (//www.ncbi.nlm.nih.gov/pmc/articles/PMC5826622/) _Immunity. _2018 Feb 20; 48(2): 202-213. Accessed 7/26/2022.
• Sauls RS, McCausland C, Taylor BN. Histology, T-Cell Lymphocyte. (//www.ncbi.nlm.nih.gov/books/NBK535433/) [Updated 2021 May 10]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Accessed 7/26/2022.

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