Topic 6 - Response to infection Flashcards
what do histamines do?
cause blood vessels to dilate - cause redness + heat. reduces pathogen reproduction.
___plasma + leucocytes are forced out capillaries -> cause swelling + pain___
4 non-specificimmune responses:
-inflamation -> due to localised infection
-fever -> hypothalamus increases body temp - reduce path production
- phagocytosis -> WBC engulf + digest pathogens
- lysozyme action -> lysozyme = enzyme in secretions e.g tears + mucus which kills bacteria by destroying their cells wall
how are infections caused
non specific responses - reasons behind them
due to localised infection
how are fevers caused
non specific responses - reasons behind them
hypothalamus increases body temp - reduce pathogen production
how is phogocytosis caused?
non specific responses - reasons behind them
WBC engulf + digest pathogens
how is lysozyme action caused?
non specific responses - reasons behind them
lysozyme = enzyme in secretions e.g tears + mucus which kills bacteria by destroying their cells wall
Apoptosis?
cell death
specific immune response incudes:
1
what type of cell
-lymphocytes
Where are lymphocytes made?
made in white bone marrow of long bones
where do lymphocytes move around?
What do they respond to?
-the body and lymphs
-respond to foreign antigens
2 main types of lympocytes
- B Cells
- T Cells
what do B Cells have on their cell membrane
membrane bound globular receptor proteins
What do B Cells produce?
(also known as?)
- produce antibodies
- (immunoglobins)
How many b cells does an embryo have
100mil b cells
When a B Cell binds to an antigen - what cells are produced?
3
- B effector cells
- Plasma cells
- B memory cells
what do B effector cells do?
- form plasma cell clones
what do Plasma cells do?
- produce antibodies - 2000/sec
what do B memory cells do?
- Provide the immunological memory to a specific antigen, allowing later rapid response
Where are T cells produced?
- in one marrow
Where are T cells active
what gland?
actuve in the thymus gland
What does the surface of each T cell have
many T cell receptors
What do T cells do?
bind?
produce?
-bind to antigens on infected body cells
- then produce further T cells
What T cells are further produced after they bind to antigens of infected body cells?
- T killer cells
- T helper cells
- T memory cells
What do T killer cells do?
chemicals….
- produce chemicals to destroy infected body cells
What do T helper cells do?
- activate plasma cells to produce antibodies and secrete osonins to label the pathogen for phagocytosis by other WBCs
What do T memory cells do?
- make up part on the immunological memory - rapidly divide when meeting a pathogen for second time - forming a large clone
2 response types
- Humoral
- Cell mediated
diff btwn Humoral ad Cell mediated?
pathogen
Humoral response - Pathogen outside cell (bacteria)
Cell mediated response - pathogen inside cell (virus)
2 stages of Humoral response:
T helper activation + effector stage
Tcells are involved in activating…?
B cells
B cells produce…?
antibodies
What does the humoral response produce ?
* are the ____ attached to cells? yes/no
* hwo are they carried?
- Antibodies
- Not attached to cells
- Carried in the blood + tissue. Fluid
What are histamines?
chemical in the non specific immune response that cause arterioles to dilate
How many antibodies do B plasma cells produce?
2000/sec
What does MHC stand for?
major histacompatability complex
what does APC stand for?
Antigen Presenting Cell
Which leucocytes complete phagocytosis
Phogocytes
3 signs of immune response:
- fever
- inflamation
- scabs
Humoral Response:
5 stages of T Helper Cell Activation:
Tip: 2 types of phagocytes split into two diff roles
- Pathogens enter body - produce chemicals, attract phagocytes (macrophages; neutrophils)
- Neutrophils - engulf + destroy
- macrophages - prepare route for specific immune response
- T cell receptor binds to MHC on APC - binding triggers T cells to reproduce -> forming clones
- clones - these cells become T Helper Cells + T Memory Cells
2 types of phagocytes
neutrophils + macrophages
what type of cells does Cell Mediated Response involve?
involves T killer cells
How are T killer cells used in the Cell Mediated Response?
respond to…?
Respond to cells that’ve changed due to pathogen
Derscribe what happens in the Cell Mediated Response
8-ish
- Infected cell is digested
- host cell displays the antigens on the MHC and body cell then becomes an APC
- T Killer Cell with complementary receptors binds to the APC
- Cytokines (secreated by active T Helper Cell) stimunlates the T Killer Cells to clone (by mitosis)
- Cells divinde to form active T Killer Cells and T Memory Cells
- Active T Killer Cells bind to APC
- They release enxymes/secreate chemicals which cause pores to form in the cell membrane (allows water in)
- The cells lyse
- initiate and constrain inflammatory responses to pathogens and injury.
*Cytokines are a broad group of signalling proteins that are produced transiently, after cellular activation, and act as humoral regulators which modulate the functions of individual cells, and regulate processes taking place under normal, developmental and pathological conditions
What happens in the Primary Response?
effectiveness?
what does this mean/cause?
what produced - from what?
- Antibodies are produced by B effector cells + T killer cell activation
- Can be days/weeks before it’s effective
- This time is when we have disease symptoms
What happens in the Secondary Response?
-2nd invasion?
-produced + by what?
-cloned? 50/50
-fast+how long lasts?
-quick + long lasting
- B cells respond quickly to 2nd invasion of same pathogen
- Antibodies produced by B Memory Cells
- Active T Killer Cells also cloned - engulf + destroy infected cells
- Some cloned become memory cells
What does pathological mean?
- Altered or caused by disease
Humoral Response:
7 Stages of the Effector stage
- Antigens from APC that are complementary to antibodies of B Cells bind and are taken in by endocytosis
- B cell acts an an APC and presents antigens to MCPS
- An activated T helper cell (from previous stage) with a complementary receptor protein to the antigens binds to the APC. Produces cytokines.
- cytokines stimulate B Cell to divide (mitosis) anf form B memory cells and B effector cells
- B effector cell differentiate into B plasma cells
- Plasma cells synthesise antibodies
- (effects of antibodies)
- T suppressor cells stop the immune response
* synthesise - make (especially chemically)
- Methyl-accepting chemotaxis proteins (MCPs) are a family of bacterial receptors that mediate chemotaxis to diverse signals
- T Suppressor Cells - a type of immune cell that blocks the actions of some other types of lymphocytes, to keep the immune system from becoming over-active
Humoral Response:
Effector Stage:
Effects of antibodies:
a. Agglutination
b. Lysis
c. Opsonisation
d. Preceipitation/Neutralisation
Effects of antibodies:
Agglutination?
microbes clump together - make phagocytosis easier
Effects of antibodies:
Lysis?
bursting of bacterial cells
Effects of antibodies:
Opsonisation?
antibodies coat microbes and mark them for phagocytes
Effects of antibodies:
Precipitation/Neutralisation
soluble toxins are made insoluble
