Flashcards in Pathology L17 Mediators of Immunity Deck (18)
Define: pleiotropism, redundancy, synergy, antagonism
Pleiotropism -> activate numerous types of responses - differentiation, growth, activation and chemotaxis
Redundancy -> functional overlap
Synergy -> between cytokines to optimise response
Antagonism -> to regulate duration and potency of response in order to prevent autoimmunity
What are cytokines?
Secreted proteins that mediate and regulate immunity (innate and adaptive immunity) and inflammation
Cytokines can act in an autocrine, paracrine and endocrine manner. What are these?
Autocrine - acts on cell that synthesized them
Paracrine - cells in the immediate environment
Endocrine - distant cells - similar to hormone
What are the 3 types of interferon?
What is the purpose of colony stimulating factor (CSF)?
Differentiates bone marrow cells to particular cells but can also have effects on mature cells
What are chemokines?
Small proteins with 2 internal disulfide brides and conserved structure that act as chemoattractants when bound to a specific receptor - help cells move to SPECIFIC places
Is the direction of chemotaxis towards higher or lower chemokine concentration?
What are the 4 families of chemokines and what differentiates them?
C, CC, CXC, CXXXC - categorised based on spacing of the 2 cysteines
What are complement proteins?
Heat labile plasma proteins activated in under certain situations that act as effector mechanisms for the innate immune system and humoral adaptive immune system
What 5 functions do complements perform in innate host defence?
Innate: Opsonisation, Initiate inflammatory response, Clearance of apoptotic debris
Adaptive: B-cell activation, T-cell priming
What are the 3 major pathways of the complement system?
Classical (antibodies), Alternative (bind to microbe), Lectin (bind to mannose)
Which is the MAIN complement protein common to all pathways that INITIATES late steps of the process?
In a clinical complement assessment, which two complement proteins are measured?
C3 and C4 serum levels
Are high C3 levels pathogenic?
No, mostly part of the acute phase response
What is the most likely infection to result from lack of C5-9 function?
Neisserial bacterial infection
Do antigen presenting cell produce cytokines?
Yes aka dendritic cells, B cells, macrophages all produce cytokines
What are some of the roles cytokines help with?
- Antigen recognition in lymphoid organs
- T-cell expansion and differentiation: each step of the T-lymphocyte life cycle is regulated by a cytokine
-Supporting effector phase of T-cell response