Granzymes are enzymes released by cytotoxic T-cells (CD8+ T-cells) and natural killer (NK) cells that help trigger apoptosis (programmed cell death) in infected, cancerous, or abnormal cells. These enzymes work together with perforins, which create holes in the target cell membrane, allowing granzymes to enter and destroy the cell from within.
How Granzymes Work (Step-by-Step Process)
1️⃣ Recognition of the Target Cell
- Cytotoxic T-cells (CD8+) or NK cells identify a virus-infected, cancerous, or abnormal cell.
2️⃣ Perforin Release
- Perforins create pores (holes) in the target cell membrane, forming an entry pathway.
3️⃣ Granzyme Entry into the Target Cell
- Granzymes pass through the perforin-formed pores and enter the cytoplasm of the infected or abnormal cell.
4️⃣ Activation of Apoptosis (Programmed Cell Death)
- Once inside, granzymes trigger a chain reaction that leads to DNA fragmentation and cell breakdown.
- They activate caspases, special proteins that break down the cell’s internal structure.
5️⃣ Cell Destruction Without Inflammation
- The infected or cancerous cell self-destructs (apoptosis), preventing further infection or tumor growth without causing excess inflammation.
💡 Think of perforins as “door openers” and granzymes as “hitmen” that enter the cell and carry out the destruction process safely.
Types of Granzymes & Their Roles
🔹 Granzyme A – Causes DNA damage and weakens the cell before apoptosis.
🔹 Granzyme B – Activates caspases, which cut apart proteins inside the target cell, leading to rapid cell death.
🔹 Granzyme C, K, M – Involved in additional immune functions, mainly in NK cells.
💡 Granzyme B is the most powerful and well-studied granzyme, playing a key role in cancer and viral infection control.
Role of Granzymes in Immunity
✅ Fighting Viral Infections – Granzymes destroy virus-infected cells, stopping the virus from spreading.
✅ Killing Cancer Cells – Help eliminate tumor cells before they grow uncontrollably.
✅ Preventing Intracellular Infections – Some bacteria hide inside human cells; granzymes help destroy the infected cells.
✅ Maintaining Immune Surveillance – Natural killer (NK) cells use granzymes to continuously scan and remove abnormal cells.
Granzymes & Disease
⚠️ Immune Deficiency – If the body lacks granzymes, it becomes more vulnerable to chronic infections and cancer growth.
⚠️ Autoimmune Disorders – If granzymes attack healthy cells, it can contribute to autoimmune diseases like lupus or rheumatoid arthritis.
⚠️ Cancer Escape Mechanisms – Some tumors develop resistance to granzymes, allowing them to evade immune destruction.
How to Support Granzyme Function Naturally
✔ Eat Immune-Boosting Foods – Zinc, selenium, and Vitamin C enhance T-cell and NK cell function.
✔ Exercise Regularly – Physical activity helps maintain immune surveillance.
✔ Reduce Chronic Stress – Long-term stress suppresses immune function, reducing granzyme activity.
✔ Get Quality Sleep – The body restores immune function during deep sleep.
Final Thoughts
Granzymes are powerful immune system enzymes that help cytotoxic T-cells and NK cells eliminate infected, cancerous, or abnormal cells. They work with perforins to enter target cells and trigger apoptosis, preventing infections and tumor growth without excessive inflammation.