Lecture 33 Flashcards
(12 cards)
what are the major immune cell communication methods?
- soluble molecules binding to receptors on cell membrane
- cell surface-bound receptors binding to cell surface bound ligand
- antigen being presented to cell surface bound receptors
how does the cell communication method w/soluble chemical messengers binding to receptors work?
- bind to receptors e.g toll-like receptors, cytokine receptors, chemokine receptors
- signal -> nucleus -> changes transcription/translation -> changes function of cell
how does the cell communication method w/Cell surface-bound receptors binding to cell surface-bound ligands work?
- alters function of one or both cells
- T and B cell
- 2 receptors
- can bind directly to antigen
how does the cell communication method w/Antigen being presented to a cell surface-bound receptor work?
- T cell receptors
- bind w/dendritic cells
- activates T cells, changes function
what is an antigen?
- Anything that has the potential to be recognised by the immune system
- foreign antigen = from outside of body
- self-antigen, immune system usually tolerant (if isn’t, is an autoimmune condition)
how does dendritic communication w/T cells work?
Activated dendritic cells :
- make cytokines that bind to receptors of T cell membranes
- Have cell surface-bound receptors that bind to T cell
surface-bound ligand (or vice versa)
- Present antigen to cell surface-bound receptors on T cells
- leads to T cell activation
what is MHC (major histocompatibility complex)?
- antigen presented from dendritic cell to T cell receptor
what are the 2 types of MHC and their features?
- MHC-1 = presents endogenous (intracellular) antigen, expressed on all nucleated cells
- MHC-2 = presents exogenous (extracellular) antigen, expressed only on antigen presenting cells e.g dendritic cells
what are cytokines and chemokines? what are their similarities?
- Both are produced by innate and adaptive immune cells as well as cells that influence the immune system (eg epithelial cells)
- cytokine = control growth and activity of immune cells, e.g interleukins, interferons
- chemokines = stimulate cell migration
how do helper T cells activate B cells?
- Making cytokines that bind to receptors on B cell membranes
- Have cell surface-bound receptors that bind to a B cell
surface-bound ligand (or vice versa) - activates B cell, B cell makes antibodies
how do B cells and complement work together?
- Antibody binding to a pathogen can trigger the classical pathway of complement activation
- complement fragments that are bound to antigen can also help activate B cells to make
antibodies
if i stand on a nail, what is the sequence of events for my body to clear the pathogen?
- Stand on nail, breaking the physical barrier (skin)
- Pathogens (eg bacteria) enter the body
- Chemical mediators lead to vasodilation and entry of phagocytic cells to the tissue to “eat and destroy”
- The complement pathway is triggered
- Dendritic cells in the skin become activated through
recognition of pathogen associated molecular
patterns - Dendritic cells move to the local lymph node
- Activated dendritic cells activate T cells via MHC
- Antigen + T cells and complement activate B cells
- B cells produce antibody
- Complement, phagocytosis and antibodies help clear the pathogen
