Immune System 1 Flashcards
What is an immunogen?
- a molecule that stimulates the immune
system to produce a response
What is an epitope ?
- part of antigen that reacts with immune effector cells or soluble antibodies
What are the 4 main types of pathogen?
• Bacteria
• Viruses
• Fungi
• Parasites i.e warms
What is a common lymphoid progenitor ?
- Derived from hematopoietic stem cell in bone marrow
- differentiates into T, B, NK lymphocytes
What is a common myeloid progenitor ?
- Derived from hematopoietic stem cells in bone marrow
- produces granulocyte and megakaryocyte
Primary lymphoid organs
• Bone marrow
• Thymus
Secondary lymphoid organs
• Spleen
• Adenoids
• Tonsils
• Appendix
• Lymph nodes
what are the 2 types of immunity ?
- Innate Immunity:
- Rapid response, no memory, fixed specificity. - Adaptive Immunity:
- Slow response, memory formation, highly specific.
what are the 2 kinds of innate immune response ?
- immediate
- induced
what are 3 features of the immediate innate immune response ?
- Barriers: Skin, mucous membranes.
- Peptides: Destroy microbes directly.
- Complement System:
what is an antigen ?
- part of the immunogen that reacts with immune effector cells or soluble anti-bodies
What are the 3 classifications of myeloid cells?
1) Granulocytes
- Neutrophil
- Eosinophil
- Basophil
2) Antigen presenting cells
- monocytes
- macrophages
- dendritic cells
3) Mast cells
what are the 3 types of APC’s ?
- monocytes
- macrophages
- dendritic cells
what are the 2 classifications of lymphoid cells ?
1) Small lymphocytes
- B cells
- Tcells
2) Large lymphocytes
- NK cells
function of bone marrow?
- B cells originate + mature
- T cells originate + leave at immature stage
function of thymus ?
- located above the heart
- immature T cells migrate to complete maturation
what is the key difference between primary and secondary lymphoid tissues ?
- primary = lymphocytes are only produced and mature
- so new immune response takes place - only in secondary
- secondary = activation of lymphocytes
what are the 3 types of secondary lymphoid tissues + functions ?
1)Lymphatic Vessels - transport lymph
2) Lymph Nodes - filter lymph
3) MALT (Mucosa Associated Lymphoid Tissue) - specialised tissue in submucosal layers of GI, respiratory, urinary tracts
eg. adenoids, tonsils , appendix, peyer’s patches
How do lymphocytes respond to infection in the lymph nodes?
- pathogens are carried to lymph nodes through afferent lymphatic vessels
- where they are trapped by dendritic cells and macrophages
- B and T cells ‘meet’ the pathogens
-become activated and undergo clonal expansion. - As lymphocytes proliferate, the lymph node increases in size, leading to swollen glands
cells in innate vs adaptive immunity
- innate = NK cells, neutrophil, basophil, eosinophil, monocyte
- adaptive = B cell, T cell
- both = macrophages + dendritic cells
what is the complement system + and what is its role in immunity?
- Group of nearly 30 serum and membrane proteins.
- Act in an orderly sequence.
- Initial activation leads to a highly regulated enzymatic cascade.
Roles: - Activated proteins bind covalently to bacteria (acting as opsonins).
- Opsonized bacteria are phagocytosed by immune cells with complement receptors.
Classical pathway of complement system
- Antibody-dependent and antibody-independent activation.
- C4b acts as an opsonin, enhancing phagocytosis.
Alternative pathway of complement system
- Can be activated independently or dependent on the classical pathway.
- C3b acts as an opsonin for phagocytosis.
- C3a/C5a are pro-inflammatory molecules, promoting inflammation.
- MAC (Membrane Attack Complex): causes lysis of pathogen
what does MAC do ?
- causes Lysis of pathogen
