Physiology: Adaptive Immune Response Flashcards
What are T- and B-cells?
B cells and T cells are both lymphocytes, derived originally from common lymphoid progenitor cells in the bone marrow
Which cells have CD4+ antigens?
T-helper cells
Describe the role of T-helper 1 cells
Secrete interferon-gamma, interleukin-2 and tumour necrosis factor (TNF-alpha)
Important in host defence against intracellular pathogens
Also has a disease role in autoimmunity and chronic inflammation
What is the function of IFN-gamma?
To activate macrophages
Describe the role of T-helper 2 cells
Secrete IL-4, IL-5 and IL-13
Host defence against helminths
Disease role in allergy (hypersensitivity type I)
Describe the role of T-helper 17 cells
Secrete IL-17 adn IL-22
Host defence against extracellular pathogens
Disease role in autoimmunity and inflammation
Describe the role of T regulatory cells
Exert a controlling and regulatory influence on immune responses
Which cells have CD8+ antigens?
Cytotoxic T-cells
Describe the role of cytotoxic T-cells
Secrete interferon-gamma and can kill cells infected by intracellular microbes (mainly viruses but also some bacteria)
Can also kill tumour cells
Which cells secrete antibodies?
B-lymphocytes
Give the five subclasses of antibody
IgG IgA IgM IgE IgD
What is “F-ab”?
The antigen-binding region of the antibody (fragment, antigen-binding)
What is “F-c”
The region of the antibody which binds to Fc receptors on other cells e.g. NK macrophages
Involved in effector function of the antibody
(Fragment, crystallisable)
What are the functions of antibodies?
Antigen-binding Neutralisation of toxins Immune complex formation Opsonisation Complement activation Cellular cytotoxicity
How do B and T cells differ in the way that they recognise/present antigen?
B cells recognise antigen directly in its native state via immunoglobulin
T cells recognise only antigen which is degraded and processed by antigen presenting cells and presented to T cells in association with MHC (HLA)
