Acquired continued Flashcards
Humoral immunity
B cells make antibodies (a y-shaped protein that neutralises pathogens)
Each antigen stimulates production of a single and specific antibody.
The B cell recognizes the different antigen on the surface of a macrophage
When a B cell meets and interacts with a specific antigen, the B cell becomes metabolically active and begins to divide.
What are the daughter cells produced from B cells dividing
Plasma cells – specialised antibody factory. After 5 to 8 days it can produce thousands of
antibody molecules per second.
Memory cells – long-lived B cells that remain in lymph tissues and are responsible for the
immunity that arises following infection or vaccination. The response of memory B cells is faster and more sensitive
Cell mediated immunity
To respond to most antigens, B cells need the assistance of helper T cells (TH cells).
T-cells contribute to your immune defenses in two major ways. Some help
regulate workings of the overall immune response, while others are
cytotoxic and directly contact infected cells and destroy them.
What are the main type of T cells
Four main types of T cells:
– Helper T Cells
– Killer T cells
– Suppressor T cells
– Memory T cells
Helper T cells
Recognise antigens on the surface of white blood cells, particularly
macrophages.
* Secrete interferon and cytokines which stimulate B cells and
cytotoxic T-cells (killer T-cells).
Killer T cells
Also called cytotoxic T cells.
Destroy abnormal body cells, e.g. virus infected or cancer cells.
Stimulated by cytokines.
Release perforin which forms pores in target cells – this allows water and ions in and leads to lysis of the target cell.
Cytotoxic T cells need to recognize a specific antigen bound to self-MHC markers.
Suppressor/Regulatory T cells
Suppressor T-cells or regulatory T-cells control the immune system when the antigen/pathogen has been
destroyed.
This prevents the immune system from damaging its own
cells
Memory T cells
Survive a long time and can give lifelong immunity from infection.
Can stimulate memory B cells to produce antibodies.
Can trigger production of killer T cells.
Role of antigen receptors in the immune response
Both B cells and T cells carry customized receptor molecules that allow them to recognize and respond to their specific targets
Role of cytokines in immune response
Cytokines are the chief communication signals of your T cells. Cytokines include interleukins, growth factors, and interferons.
Lymphocytes, including both T-cells and B-cells, secrete cytokines. Many of these cytokines are also known as interleukins because they serve as a messenger between white cells, or
leukocytes.
Interferons are naturally occurring cytokines that may boost the immune system’s ability to recognize cancer as a foreign invader.
