Unit 2- Cells & Tissues in the Immune System Flashcards
all cells of the immune system are derived from _____ _____ in the ______ _______ except T Cells which are made in the _________
stem cells
bone marrow
thymus
What is Clonal expansion?
lymphocyte receptors with varying affinity for the antigen- the cell with the highest affinity for the most abundant antigen will have growth advantage
What is the role of B Cells?
- when B cells encounter an antigen it gives rise to plasma cells (plasma cells produce antibodies)
What is the role of T Cells?
recognise peptide fragments of antigen
What two types of chains does an antibody contain?
two heavy chains & two light chains
What is the top of the antibody known as? What about the bottom?
Top- variable region
Bottom- constant region (links the antibody to other immune defence cells)
What are Cytokines?
chemical messengers secreted by the cells of the immune system
What do Cytokines do?
- bind to receptors on target cells
- encourage cell growth, cell activation & direct cellular traffic
What are Cytokines also known as? Why?
Interleukins
they serve as messengers between white blood cells/ leukocytes
What are and what is the role of Natural Killer Cells?
Cytotoxic cells containing granules filled with potent chemicals that kill on binding
Macrophages are called different things depending on their _______ but they’re all part of the _____-_______ _____
location in the body e.g. Kupffer cells (liver), monocytes (blood)
Reticulo-Endothelial System (RES)
What are Mononuclear Phagocytes activated by?
T Cell Cytokines
What do Dendritic cells do?
Where are they found?
initiate adaptive immune response & activate T cells
immature dendrites reside in peripheral tissue & migrate to lymph nodes as they mature
What are Granulocytes?
white blood cells
What are the three types of Granulocytes?
Briefly describe their appearance?
Neutrophil- darkly stained structures but light cell staining
Eosinophil- medium, staining & visible circular structures
Basophil- darkly stained
What do Neutrophil Granulocytes do?
express receptors for immunoglobulin & are involved in the acute inflammatory response
What is the role of Eosinophil Granulocytes?
carry receptors for IgE & are involved in the destruction of IgE coated parasites
Also respond to allergen
What do Basophil cells do?
secrete chemicals responsible for immediate hypersensitivity following antigen induced aggregation
Give examples of Primary Lymphoid Organs?
Bone Marrow (develop mature B cells) Foetal liver (haemotopoesis)
What are some Secondary lymphoid organs?
Spleen
Lymph Nodes
Mucosal- associated lymphoid tissue e.g. gastrointestinal, respiratory tract
What are Lymph Nodes? Where are they found and what is their role?
small, bean shaped structures that are found along the lymphatic routes in the body
Contain specialised compartments where immune cells congregate and where they encounter antigens
What is Red Pulp? Where is it found & What else does it contain?
Found in the Spleen
Red Pulp is a site of red blood destruction also contains White Pulp which is where lymphocytes respond to blood-borne pathogens
What is Opsonisation?
the identification of an invading pathogen
Give examples of Cells involved in Phagocytosis?
Macrophages
Neutrophils
Dendritic Cells
What is the Complement Cascade?
the activation of one protein/ enzyme activates the next protein in the cascade.
Which type of immunity is this:
Foreign agent is recognised by lymphocytes & acquires a memory towards it
Adaptive Immunity
Upon engagement with an antigen B Cells release ______ whereas T cells release ________
Antibodies
Cytokines
What are the three ways Antibodies work?
Briefly describe each mechanism.
- Neutralisation- blocking the biological activity of their target molecule
- Opsonisation- interact with receptors and allowing them to recognise and respond to the antigen (uses macrophages, neutrophils, basophils etc)
- Complement Activation- cause direct lysis by complement recruitment