U4 L2 Innate Vs Adaptive Immunity Flashcards
What are the first, second and third lines of defence?
1st - physical and chemical barriers
2nd - innate response
3rd - adaptive response
What are four key characteristics of innate response?
• rapid response
• Reacts essentially in same way in repeated exposures
• Exists at birth
• Non-specific and indiscriminate
• No immune memory
Example: Innate response includes inflammation and phagocytosis
What are four key characteristics of adaptive response?
• specific to epitope/antigen on a pathogen
• Has immune memory
• Relies on mechanisms that develop as a result of infection
• Distinguishes between self and non-self
Where do blood and immune cells originate from?
Hematopoietic stem cells that then differentiate into either myeloid progenitor or lymphoid progenitor cells
What three kinds of cell originate from lymphoid progenitor cells?
T cells, B cells and NK (natural killer) cells
What are the three most important phagocytosing cells?
Dendritic cells, neutrophils and macrophages
What kinds of cells originate from myeloid progenitor cells?
Mast cells, granulocytes (e.g. neutrophils, eosinophils), dendritic cells, macrophages
What are the two subclasses of T cells and how do they differ?
Helper T cells - aid in activating other immune cells e.g. B cells
Cytotoxic T cells - directly kill cells infected with viruses
Natural killer cells are of the lymphoid progenitor lineage so why are they considered part of the immune response?
They have no antigen specific receptors
What makes natural killer cells cytotoxic?
Their granules - contain proteins such as performing and proteases known as granzymes which can break down cells
What is meant by the term ‘naive’ with respect to lymphocytes?
Have not yet encountered an antigen
Example sentence: Naive lymphocytes have not been exposed to any antigens.
What is meant by ‘primary’ adaptive immune response?
Response to initial exposure of an antigen
What happens during primary adaptive immune response?
• activation, proliferation and differentiation of T cells
• Generation of sub population alongside lymphocytes that become memory cells
What is the main function of a B cell?
To secrete antibodies as plasma cells
What is meant by ‘secondary’ or ‘tertiary’ adaptive immune response?
Secondary immune response refers to the second exposure of a particular antigen in the body, tertiary refers to third exposure etc etc
How does each adaptive response to the same antigen differ?
Each subsequent response is likely quicker and more effective
Adaptive immunity does not need to be maintained through repeated exposure as original memory cells are usually long lived
How long does adaptive immune response take
On average 4-7 days but an be up to 2 weeks (considerably longer than innate)
Why are booster vaccinations sometimes necessary?
To enable full immunity of adaptive response to develop
What is meant by ‘effector cells’?
B and T cells mature into effector cells upon activation
What is a memory cell?
An antigen-specific B or T lymphocyte that immediately becomes an effector cell upon re-exposure to the same pathogen
Why are scientists working to develop vaccines that are applied via intranasal, oral, aerosol routes?
Injected vaccines elicit systemic immune response, with little effect on mucosal response but many pathogens are deposited ad replicate in mucosal compartments Mucosal-administered vaccines elicit mucosal and systemic immunity
What is meant by artificial immunity?
Intentional exposure to small quantities of a pathogenic antigen, giving immunity
