Cytokines vs Chemokines- Definition and 8 Major Differences


Cytokines and chemokines are two types of molecules that play important roles in the immune system. They are both secreted by various cells in response to different stimuli, such as infection, inflammation, injury, or stress. They act as messengers that communicate with other cells and influence their behavior, such as growth, differentiation, activation, migration, and death .

Cytokines are a broad family of proteins that can affect many aspects of immunity, such as innate and adaptive responses, hematopoiesis, wound healing, and tissue homeostasis. They include several subfamilies, such as interleukins (ILs), interferons (IFNs), tumor necrosis factors (TNFs), colony-stimulating factors (CSFs), and transforming growth factors (TGFs). Each cytokine has a specific receptor on the target cell that binds to it and triggers a signal transduction pathway that leads to a cellular response .

Chemokines are a special type of cytokines that are mainly involved in directing the movement of cells, especially white blood cells (leukocytes), to the sites of infection or damage. They create a concentration gradient that attracts the cells along it towards the source of chemokine production. They also regulate the trafficking and positioning of immune cells within the tissues and organs. Chemokines are classified into four subfamilies based on the arrangement of cysteine residues in their structure: CXC, CC, CX3C, and XC .

Cytokines and chemokines are essential for the coordination and regulation of immune responses. However, they can also cause harmful effects if they are overproduced or dysregulated. For example, excessive or chronic inflammation can result from an imbalance of pro-inflammatory and anti-inflammatory cytokines. Similarly, abnormal chemokine expression can contribute to autoimmune diseases, allergies, cancer, and viral infections . Therefore, understanding the functions and interactions of cytokines and chemokines is important for developing new therapies for various immune-related disorders.