Adaptive Immunity Flashcards
What cells are involved in humoral immunity?
B cells
What cells are involved in cell mediated immunity?
T cells
What do kinins do?
A group of substances formed in the body tissue after injury, which cause vasodilation and smooth muscle contraction, capillary permeability, attract neutrophils, monocytes, lymphocytes to area (chemotaxis)
What are pyrogens?
Molecules that send messages to hypothalamus to induce immune responses such as fever
When do adaptive immune responses develop?
Only after exposure to or immunization with a substance or antigen
How are the B and T cell receptors generated?
B and T cells express somatically generated antigen specific receptors that are not germline encoded but rather are the transitional products of multiple genes that are pieced together by gene rearrangements taht occur during development
Can T cells bind to antigens directly?
No, they do not bind to antigens directly. They recognize and bind to antigenic peptides when they come in contact with antigen presenting cells (APCs) such as macrophages and dendritic cells that display processed, major histocompatibility complex (MHC) bound peptides derived from antigen
How does T cell activation greatly facilitate the activation and differentiation of B cells responding to antigen?
By the action of T cell derived cytokines that bind to specific cytokine receptors expressed on B cells
What does T cell dependent antigens mean?
That B cells are dependent on T cells for optimal antibody responses to most antigens
What happens to T and B cells in primary lymphoid organs?
This is where the maturation of B and T lymphocytes into antigen recognizing lymphocytes occurs. In other words, these are the organs where gene rearrangements occur to generate functional antigen specific BCR and TCR expressed by B and T cells
Where do B cells mature (primary)?
Bone marrow
Where do T cells mature?
The thymus
What are secondary lymphoid organs?
After maturation, B and T cells migrate through bloodstream and lymphatic system to secondary lymphoid organs, which is where antigen driven activation (proliferation and differentiation) of B and T cells occur
What are some of the secondary lymphoid organs?
Spleen, appendix, lymph nodes, tonsils
How is thymus gland formed?
It is derived from the endoderm of the third and fourth pharyngeal pouches
What does lymphoepithelial mean?
Consisting of lymphocytes and epithelial cells—– Thymus is a lymphoepithelial organ and consists of epithelial cells organized into cortical (outer) and medullary (central) areas that are infiltrated with lymphoid cells (thymocytes)
What are the two major functions of secondary lymphoid organs?
- They are highly efficient in trapping and concentrating foreign objects
- They are the main site of production of antibodies and the induction of antigen specific T lymphocytes
MALT
mucosa associated lymphoid tissue—- where lymphoid aggregates occur
GALT
gut associated lymphoid tissue
BALT
bronchus associated lymphoid tissue
What is the major organ of the body in which antibodies are synthesized?
The spleen— highly efficient in trapping and concentrating foreign substances carried in the blood
White pulp of the spleen
Rich in lymphoid cells
Red pulp of spleen
Contains many sinuses as well as large quantities of erythrocytes and macrophages, and some lymphocytes
Where are B cells located in the spleen?
In germinal centers— after antigenic stimulation the germinal centers carry large amounts of B cells and plasma cells which synthesize and release antibodies
