Cell Recognition And The Immune System Flashcards
Where do you find antigens?
Cell surface membrane of foreign cells
Where do you find MHCs?
Cell surface membrane of non-self cells
What antibodies would someone with blood type A have?
Type B antibodies
What antibodies would someone with blood type B have?
Type A antibodies
What antibodies would someone with blood type O have?
Type A and type B antibodies
Which blood types can donate blood to blood type AB?
A, B, AB and O (all)
What are the two main types of defence mechanisms?
Specific (vertebrae only) and non-specific (vertebrae and non-vertebrae)
What is the non-specific defence mechanism?
Physical barriers (eg. Skin) and phagocytosis
What is the specific defence mechanism?
Cell mediated response and humoral response
Describe the cell mediated response
Cytotoxic T lymphocytes attack infected cells (intracellular pathogens) so infection doesn’t spread further
Describe the humoral response
B lymphocytes attack non-self species outside of the body cells (extracellular)
Outline the stages of the humoral response
Phagocytic B cell engulfs pathogen
Pathogen’s antigens are processed and presented on the outside of B cell
Activated T-helper cell (CD4+) binds to presented antigen with specific receptor, triggering the B cell to undergo mitosis and clonal selection
This forms a plasma cell or a memory cell
The plasma cell produces specific monoclonal antibodies (primary response)
The memory cell stays in the immune system for future infections (secondary response)
What do antibodies cause?
Opsonisation (more favourable to phagocytes) and agglutination (clumps to be better seen) so phagocytes can ingest and kill pathogen
What is active immunity?
Eg. Infection or vaccination
This stimulates the production of memory cells so longer term protection
What is passive immunity?
Eg. Maternal antibodies and monoclonal antibody treatment
No memory cells are made (only given antibodies) so just primary response and short term protection
What does cytotoxic mean?
Toxic to cells
What cell does HIV infect?
T-helper cells (CD4+)
What are cytokines?
Chemicals released by leukocytes (wbc) that trigger symptoms and make you feel ill
Describe activation of T-helper cells
Antigen presenting cell (APC) engulfs pathogen and goes through phagocytosis
APC processes and presents pathogen’s antigens
T-helper cell binds to presented antigen triggering cloning by mitosis
This becomes an activated T-helper cell
Describe the roles of T-helper cells
Can act as memory T-helper cells
Can stimulate B cells into clonal selection and mitosis
Can stimulate phagocytosis
Can activate cytotoxic T cells (CD8+)
What is a monoclonal antibody?
Identical types of one specific antibody produced by one type of plasma cell
What is a pathogen?
An agent that causes disease
What is another name for red blood cell?
Erythrocyte
What is another name for white blood cell?
Leukocyte
What makes a successful vaccination programme?
To be able to produce large amounts to vaccinate vulnerable people at reasonable cost
Side effects are rare
Storage and transportation is manageable
Trained staff to deliver it
Possible to achieve hers immunity
What are the types of ELISA tests?
Direct and indirect
What is a direct ELISA test?
Using a single antibody that is complementary to the antigen being tested for
What is an indirect ELISA test?
Using 2 different antibodies known as primary and secondary
What does an ELISA test do?
Used to see if patients have antibodies to a specific antigen (test for infections by pathogens)
What does ELISA stand for?
Enzyme linked immunosorbent assay
What happens during an ELISA test?
Enzymes are attached to antibodies
When these enzymes react to a certain substrate a coloured product is formed (positive result)
What does HIV stand for?
Human immunodeficiency virus
What does AIDS stand for?
Acquired immunodeficiency syndrome
What is a retrovirus?
RNA virus
Why are viruses non-living (acellular)?
Cannot replicate alone so require a host cell to process RNA
What do antiretroviral drugs do?
Keep the virus in ‘latency’
