Cellular immunity

Definition

Cellular immunity is a type of immune response that involves the activation of T-cells to fight pathogens, especially intracellular pathogens like viruses. It does not involve antibodies but relies on direct cell-mediated mechanisms to eliminate infected cells.

5 Must Know Facts For Your Next Test

1. T-cells are central to cellular immunity and differentiate into various types such as helper T-cells and cytotoxic T-cells.
2. Helper T-cells (CD4+) assist other cells in the immune system by releasing cytokines.
3. Cytotoxic T-cells (CD8+) directly kill infected cells by inducing apoptosis.
4. Major Histocompatibility Complex (MHC) molecules present antigenic peptides to T-cells, which is crucial for their activation.
5. Memory T-cells are formed after an initial infection and provide faster responses upon subsequent exposures to the same pathogen.

Review Questions

• What role do helper T-cells play in cellular immunity?
• How do cytotoxic T-cells eliminate infected cells?
• What is the significance of MHC molecules in activating T-cells?

Related terms

Humoral Immunity:

A type of adaptive immunity mediated by B-cells and antibodies targeting extracellular pathogens.

Antigen Presentation:

The process by which protein fragments are displayed on the surface of a cell for recognition by T-cells.

Cytokines:

Signaling proteins released by cells, particularly those in the immune system, that mediate and regulate immunity, inflammation, and hematopoiesis.