Ch. 11 Specific Resistance to Infection Flashcards
Where are lymphocytes produced and where are they located
- Produced in: bone marrow, some in lymphoid tissue
- Roam the body- blood, tissue fluid, lymph
What are macrophages and how are they involved in specific defense
- Consume foreign substances and microorganisms through phagocytosis
- Involved in specific > alerts immune system of presence of foreign material
Define immune system
different types of cells that occur in most organs and protect against foreign invader, abnormal cells
define immune response
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: a response triggered by a foreign substance or microorganisms invading body A homeostatic mechanism
Name and explain the two parts of the immune response
- Humeral Response/ Antibody Mediated Immunity
- Production of special proteins (antibodies) circulating body + attack invading agents - Cell-mediated Response
- Formation of special lymphocytes that destroy invading agents
- Both aspects involve lymphoid tissue
What is lymphoid tissue and what is it composed of
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Lymphoid Tissue: tissue containing lymphocytes and macrophages, mostly in nodes, bone marrow thymus - Composed of B and T Cells o B-Cells provide antibody – mediated immunity o T-Cells provide Cell-mediated immunity
Explain the production of t and b lymphocytes
- Both cells produced in bone marrow, end up in lymphoid tissue
o Mature by following two different routes b/w bone marrow and lymphoid tissue
♣ Half of cells produced by bone marrow > thymus> mature to T Cells> incorporated into lymphoid
♣ Other half mature in bone marrow> become B Cells > lymphoid
Define antigen
any substance capable of causing formation of specific antibodies when introduced into tissues
what is the immune system programmed to distinguish between
- Self-antigen: Large molecules produced in a person’s own body does not cause immune response
- Non-self antigens: Foreign compounds that do trigger immune response
Define antibodies and what group of proteins do they belong to
a specialized protein produced in response to a specific non self antigen, binds with it and neutralizes/destroys
immunoglobins
what is an antigen antibody complex
- Antibody produced in response to an antigen can combine with that antigen= antigen-antibody complex (specific active sites)
What does antibody mediated immunity involved
- production and release of antibodies into the blood and lymph
= antibody mediated immunity
what type of cell is involved in AMI
B Cells
what are the three steps of AMI
- Foreign antigen reaches lymphoid tissue
- Antigen activates B Cell> they enlarge, divide into groups of cells called a clone (group of cells with same genetic characteristics)
- Clone cells become either
a. Plasma cells (a cell that develops from a B cell and produces antibodies)
o Secrete specific antibody’s capable of attaching to the active site of the antigen
o These antibodies circulate blood, lymph, extracellular fluid to reach site of invasion of micro-organisms or foreign material
b. Memory cells (a type of cell that recognises an antigen to which body has previously been exposed to)
o Can spread through all body tissues
o To allow more rapid response should antigen enter again
Define primary response and its characteristics
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Primary Response: a response of immune system to first exposure of antigen o Fairly slow (days to build up large a# of antibodies o Slow production of antibodies from B Cell o Plasma cells secrete > level of antibody increase > reach peak > decline
Define secondary response and its characteristics
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Secondary Response: response to second or subsequent exposure to antigen (more fast + intense that first) o Plasma cells form quickly> antibody level in blood rises (higher than primary) o Quick response= antigen shows little noticeable effect on body
What are the 6 ways antibodies work
o Combine with foreign enzymes or bacterial toxins, or inactivate them by inhibiting reaction with other cells
o Bind to surface of viruses + prevent from entering cells
o Coat bacteria so that the bacteria more easily consumed by phagocytes
o Cause particles such as bacteria, viruses, foreign blood cells to clump together= agglutination
o Dissolves organisms
o React with soluble substances to make them insoluble and thus more easily consumed by phagocytes
What are the 6 ways antibodies work (cheat words)
inactivate prevent entering coat agglutination dissolve insoluble
What are the three steps in cell mediated immunity
- Foreign antigen enters body > particular type of T-Cell (specially programmed for that antigen) is activated/sensitized
- Only occurs after B cell encounters foreign antigen, travels to nearest node and presents it to T-Cell - Sensitized T-Cell enlarge and divide forming clone
- Clone cells either:
a. Remain in lymphoid as memory cell (able to recognise original invading antigen and initiate faster response)
b. Develop further producing three different types of T-Cells
what are the three cells that T cells develop into
killer helper and suppressor
what do killer t cells do
- Migrate to site of infection > deal with invading agent
- Attach to invading cells + secrete substance that will destroy the antigen + then search for more antigens
what do helper t cells do (3)
- Secrete # of substances that:
o Cause lymphocytes at infection site to become sensitized // intensifying response
o Attract macrophages to place of infection so that macrophages can destroy antigens by phagocytosis
o Intensify phagocytic activity of macrophages
what do suppressor t cells do
- act when immune activity becomes excessive or infection has been dealt with successively
- Release substances that inhibit T and B cell activity= slow down immune response
Define artificial and natural immunity
- Natural Immunity: immunity that occurs without any human intervention
- Artificial Immunity: immunity produced by giving a person an antigen, which triggers the immune response, or by giving person antibodies to an infecting agent
define active and passive immunity
Passive: immunity produced by introduction of antibodies from another person
active:: immunity produced by the body manufacturing antibodies against a foreign antigen
Examples of Natural passive and Ariticial passive
- Natural passive= e.g. can occur when antibodies passed from mother across placenta/ through breast milk to developing foetus
- Artificial passive= e.g. person injected with antibodies to combat a particular infection
Examples of Natural active and Ariticial active
- Natural Active: can result from actual attack of the disease
- Artificial active: from injection of antigens associated with disease
Define immunisation
programming immune system so that body can respond rapidly to infecting microorganisms
define vaccination/ vaccine
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Vaccination: introduction of antigens to a person so that they acquire immunity without suffering from illness Vaccine: an antigen preparation used in immunization
what are the four types of traditional vaccines
- Living attenuated
- dead
- toxoids
- sub unit
Describe, pros and cons of live attenuated vaccines
- Describe: (of reduced virulence) creating a reduced ability to produce disease
- // immunized person does not contract symptoms but manufactures antibodies against antigen
- Pros: Prolonged response, rapid immunity, known to be efficient
- Cons: virulence in susceptible hosts, potential reversal of attenuated
Describe, pros and cons of dead microorganisms
- Describe: inactivated microorganisms incapable of causing disease
- Pros: no mutation or reversion, more stable than attenuated
- Cons: Not prolonged as live attenuated microorganisms, weaker response (multiple shots)
Describe, pros and cons of toxoids
- Describe: Inactive toxins
- Pros: no need for whole organism
- Cons: only effective is disease caused solely by toxin
Describe, pros and cons of subunit
- Describe: Fragment of organisms instead of whole dead or live
- Pros: can be manipulated to increase immunogenicity, doesn’t use whole organism
- Cons: costly, not as immunogenic as natural
define herd immunity
a type of ‘group’ immunity that occurs when such a high proportion of people a population, about 95%, are immunized that those who are not immune are protected
