Animal Defences Flashcards
Phases of defence response
- Recognition
- Activation
- Effector
Recognition phase
Discriminates between self and non-self
Activation phase
Recognition event that leads to mobilisation of cells and molecules to fight invaders
Effector phase
Mobilised cells and molecules destroy invader
Nonspecific defence
Innate, rapid, barriers like skin, phagocytic cells
Specific defence
Adaptive, specific to pathogen E.g antibiotics- slow to develop and long lasting
Lymphoid tissue
Essential parts of defence system
Thymus
Bone marrow
Spleen
Lymph nodes
What is lymph in the body
Fluid derived from blood and other tissues
White blood cells
Phagocytes
Lymphocytes
Granulocytes
White blood cell
vesicles containing defensive enzymes
Four key protein types
Antibiotics
Major histocompatibility complex (MHC)
T cell receptors
Cytokines
Antibiotics
Produced by B cells
Binds to specific substances identified by the immune system
T cell receptors
Recognise and bind non-self molecules on other cells
Cytokines
Signalling molecules that alter behaviour
Granular cells
Basophils
Eosinophils
Neutrophils
Mast cells
Basophils
Release histamine
Which may promote development of T cells
Eosinophils
Kill antibody coated parasites
Neutrophils
Stimulate inflammation
Mast cells
Release histamine when damaged
Lymphoid progenitor cell
Produce
B lymphocytes
T lymphocytes
Natural killer cells
T lymphocytes
Kill virus infected cells
Or
Regulate activities of other white blood cells
B lymphocytes
Differentiate to form antibody producing cells and memory cells
Natural killer cells
Double functional
Non specific defences
Skin
Normal flora
Tears, nasal mucus + saliva
Mucous membranes
Pathogens in the digestive tract
Killed by gastric juices
Or
Bile salts in the small intestines
Pathogens that penetrate the surface
Activation of defence cells
Secretion of digestive proteins
Complement system
Made from antimicrobial proteins
- activated by the immune system
- proteins acts in cascade
Complement proteins types of defences
Three types of defences
1. Attach to microbes and mark them for phagocytes to engulf
2. Activate inflammation response and attract phagocytes to site of infection
3. Lyse invading cells
Interferons
Signalling molecule produced by infected cells.
Increase the resistance of other cells
How do interferons increase the resistance of other cells
- Binding to receptors on noninfected cell membranes to stimulate a signalling pathway that inhibits viral reproduction
- Stimulating cells to hydrolyse pathogens’ proteins to peptides
Phagocytes
Travel freely in the lymph and circulatory system. They engulf foreign cells and have agents inside that kill pathogens.
Natural killer cells
Lymphocyte that detects virus infected cells. Initiate apoptosis and can interact with specific defence mechanisms.
Inflammation
Response to injury
- mast cells
- tumour necrosis factor
- Prostaglandin
- Histamine
Mast cell
Adhering to skin and organ linings; release chemical signals
Tumour necrosis factor
Cytokine that kills target cells and activates immune system
Prostaglandins
Dilate blood vessels and interact with nerve endings, response for pain
Histamine
Amino acid derivative that leads to itching and allergic reactions
Symptoms of inflammation
Blood vessels in area are dilated
Capillaries become ‘leaky’ plasma moves into tissue (causes swelling), along with complement proteins and phagocytes. Phagocytes engulf invaders and dead tissue and produce cytokine
Toll like receptors
Recognise what is expressed by pathogen and consider response, these proteins are part of protein kinase cascade
Passive immunity
Specific
Development of immunity from antibiotics received from another
Specific immune system
4 key traits
Specificity
Ability to distinguish self from non self
Diversity
Memory
Specificity
Lymphocytes are crucial
T cell receptors and antibodies bind to specific antigens
What are the specific sites on the antigen called
Antigenic determinants
Or
Epitopes
Distinguish from self and non self
Self marker (MHC) - self
An antigen - non self
Two specific immune system responses
Hormonal immune response
Cellular immune response
=simultaneous
Hormonal immune response
Abs react with Ags in blood, lymph and tissues fluids
B cell has the same specific receptors as ab on its surface
Antigens bind to b cell, which then make multiple copies of the Ab
Cellular immune response
Detects and destroys virus infected cells and mutated cells
T cell receptors bind to specific Ags, initiating immune response that results in the destruction of foreign cells
What is diversity generated by?
DNA changes
What kind of daughter cells are produced by activated lymphocytes
Effector cells
Memory cells
Effector cells
Carry out attack
Effector b cells secrete Abs
Effector T cells secrete cytokines
Memory cells
Long lived cells that can divide on short notice to produce effector cells
Three ways vaccination modifies pathogens so they will not cause disease
- inactivation by heat or chemicals
- attenuation of virulence by mutation
- recombinant DNA
What is clonal deletion
any immature B + T cells that show potential to mount an immune response to self antigens undergo apoptosis
What cells are the basis of the humeral immune response
B cells
What protein class do antibodies belong to
Immunoglobulins
