Immunity & Antibodies Introduction Flashcards
What is immunity
Immunity is an organism is the ability to defend itself against infectious agents, foreign bodies and proteins and catastrophic cell dysfunction e.g. cancer
What is immuno deficiency
Immunity fails can be genetically inherited or acquired during life e.g. AIDS
What is allergy and hyper sensitivity
Immune responds inappropriately to antigens
What is immune tolerance
State of immunological nonreactivity to an antigen – remain quiet until needed
What is an autoimmune disease
An immune response to self tissue, a breakdown of tolerance
Are all antigens harmful to us
No many antigens are not harmful e.g. our own cells and tissues, food, commensal organisms (skin and gut flora)
What is innate immunity
System that is genetically coated in genome– responds rapidly but lack ability to adapt
What is adaptive immunity
It takes time to develop but can recognise a vast variety of antigens – it has a memory function if a pathogen enters again it is quicker to deal with it
Part of lymphoid tissue
Lymph-node‘s, red bone marrow, spleen, thymus, leukocyte (WBC’s), hematopietic stem cell
What does the red bone marrow produce
All blood cells – B and T lymphocytes
The spleen is an emergency store of what
Emergency blood store, blood is cleansed of pathogens and debris
What does the thymus have in it
T lymphocytes
Hematopietic stem cell is
Self renewing and they differentiate into all immune cells – they can turn into lymphoid progenitor which goes to dendritic cells and B&T cells Or or turn into myeloid progenitor which turned into erythrocytes e.g. neutrophils and macrophages
Where do B&T cells circulate in
The blood and lymphatic system- they move between the structures through high endothelial venules HEV
B cells can access
All areas of the body and so can their antibodies
Lymphocyte recirculation allows
Lots of lymphocytes to interact with antigens
How often does 1 lymphocyte travel around the system
1 to 2 times a day
What proportion of lymphocytes will bind to one particular antigen
One in 100,000
Leucocytes communicate using
Cytokines and chemokines- They bind to specific receptors on the surface of the cell which triggers signal transduction and change in gene expression which causes a change in cell function
What type of signalling does leucocyte communicate do
Autocrine, paracrine, juxtacrine and rarely endocrine
Antibodies are
Glycoproteins and each antibody has a specific antigen
What is the epitope
The part of an antigen which the antibody binds to
In naive B-cell the antibody has a
B-cell receptor, once it is activated by antigen cross-linking and cytokine mediated simulation by T cells cells
The structure of antigen binding site remains
Identical throughout
In clonal expansion each B&T cell expresses
Its own antigen receptor
How does clonal expansion work
The binding of antigen triggers clonal expansion – it’s stimulated by growth factors e.g. interleukin-2, finding events can cause inability to subsequently be activated or cell death by apoptosis
CD4+ expresses
CD4 and is likely to be a T-helper cell
CD8+ expressed
CD8 and is likely to be a cytotoxic cell
Immunoglobulin isotopes depend on
Stalk structure which causes a different immunoglobin isotope which causes a different function
What time in affect on antibody function
Affinity and avidity
What is avidity
The cell has 2+ antibody binding arms which help keep antibody bound and in place
An increase in antibody arms increases
The ability to stick to arms and stay stuck
Types of leucocytes
Macrophage, neutrophil, basophil, dendritic cell, B-cell, T-cell, eosinophil
Macrophage function
Phagocytic, highly migratory , professional antigen presentation 
Neutrophil function
Highly abundant and migratory, coordinate inflammatory response
Eosinophil function
Involved in host defence against nematodes and other parasites
Basophils function
Involved in hosts defences against multicellular parasites
Dendritic cells function
The most adept of the family of antigen-presenting cells
B-cell function
Adaptive, produce antibodies that bind to antigens on pathogens, exhibit immunological memory
T cell function
Adaptive, involved in killing virus infected cell, involved in coordinating immune responses – orchestrators of activation/termination
Stages of the inflammatory response
Tissue damage causes release of vasoactive and chemotactic factors that trigger a local increase in bloodflow and capillary permeability
Permeable capillaries allow an influx of fluid and cells
Phagocytes migrate to site of inflammation (chemotaxis)
phagocytes and anti bacterial exudate destroy bacteria
Part of an antibody
Heavy-chain and light chain with disulphide bonds between them, antigen binding site
