Defence against parasitic attack Flashcards
What are the type types of immune responses in mammals
Specific and non-specific defences
Non-specific defences
Physical barriers Chemical secretions Inflammatory response Phagocytes Natural killer cells destroying cells infected with viruses
Examples of Physical barriers
non
Epithelial tissue blocks entry of parasites.
Hydrolytic enzymes in mucus, saliva and tears destroy bacterial cell walls
Low pH environments of the secretions of stomach, vagina and sweat glands denatures cellular proteins of pathogens.
What happens when injured cells release signalling molecules
non
This results in enhanced blood flow to the site, bringing antimicrobial proteins and phagocytes
How do epithelial cells present a barrier
non
They present a physical barrier by blocking the entry of parasites
How do hydrolytic enzymes present a barrier
non
in mucus, saliva and tears destroy bacterial cell walls.
How does low pH present a physical barrier
non
low pH areas in the stomach, vagina and sweat glands denatures cellular proteins of pathogens
How do lysosomes kill parasites
non
Use powerful enzymes contained inside them by engulfing them and storing them inside a vacuole in the process of phagocytosis
How do natural killer cells kill parasites
non
They identify and attach to cell infected with viruses, releasing chemicals that lead to cell death by inducing apoptosis
What is specific cellular defences
A range of white blood cells constantly circulate, monitoring the tissues
What happens when cells become invaded?
The cells release cytokines
What does the release of cytokines result in?
Increases blood flow resulting in non-specific and specific white blood cells accumulating at the site of infection or tissue damage
In mammals what recognises parasite antigen
They contain many lymphocytes, each possessing a receptor on its surface
What happens when an antigen binds to a lymphocytes receptor
That lymphocyte then divides and produces a clonal population of this lymphocyte
What are the processes antibodies go through?
Some will produce antibodies, others can induce apoptosis in parasite-infected cells.
What regions do antibodies possess (AA)
They possess regions where the amino acid sequence varies greatly between different antibodies
What does the differing amino acid sequence give
Gives the antibody its specificity for binding antigen
What forms when an antigen binds to the differing binding site
The antigen-antibody complex is formed
What is resulted from the antigen-antibody is formed
Results in the inactivation of the parasite, rendering its susceptible to a phagocyte, or can stimulate a response that results in cell lysis
What can also result in the antigen-antibody complex
Memory lymphocytes
/How are memory lymphocytes formed
initial antigen exposure produces memory lymphocytes cells specific for that antigen
What can memory lymphocytes do?
They can produce a secondary specific response when the same antigen enters the body in the future.
What happens when the secondary specific response of memory lymphocytes is used?
It enhances the production of antibodies in terms of speed of production, concentration in blood and duration.
