Immunity Flashcards
Basically, what defines the innate immune system?
It is inborn and operates throughout life
What defines the Adaptive immune system?
It changes in response to the pathogens it encounters and is characterised by the development of immunological memory
What are cytokines?
Small soluble proteins involved in cell-cell signalling
What does autocrine mean?
Acts on cell secreting in
What does paracrine mean?
Acts on adjacent cells
What does endocrine mean?
Acts on cells and organs at remote sites
What are chemokines>
Subgroup of cytokines that recruit phagocytes and cause diapedeses
What do monocytes differentiate into in tissues?
Macrophages
What is the most abundant cell of the innate immune system?
Neutrophils
What cells release Histamine?
Mast cells and Basophils
What cell releases Histaminase?
Eosinophils
What PRR mediate phagocytosis?
Fc, beta-glucan and complement receptors
What PRR’s mediate an inflammaory response?
TLR’s, CLR’s and RLR’s
What are the symptoms of inflammation?
swelling, redness, heat, pain and loss of function
What are the 3 complement pathways?
Classical, alternative and mannose binding lectin pathway
What do all three complement pathways result in?
Formation of the membrane attack complex
What complement proteins form the membrane attack complex?
C5b-9
Where are complement proteins produced
In the liver
Once a dendritic cell has encountered an antigen where does it migrate to?
Paracortex of lymph node
What do dendritic cells do in the local lymph node?
They present their antigen to T-cells
What are the two different types of T-cell?
Th (CD4+) cell and T cytotoxic (CD8+) cell
What do CD4+ cells respond to?
MHC 2+ Ag presentation
What do CD8+ cells respond to?
MHC1+Ag presentation
What are B-cells activated by>
T helper cells and macrophages presenting antigen
What happens when CD4+ Th1 cells are activated?
They proliferate - secreting IL2 (self stimulate)
Secrete IFN-gamma and TNF-alpha
What does IFN-gamma do?
Increases ability of macrophages to lyse phagocytosed pathogens
What happens when CD8+ cells are activated?
produce cytolytic enzymes which are injected into the cell to trigger apoptosis
What happens when CD4+ Th2 cells are activated?
They self stimulate with IL4 which also causes B-cell proliferation
What happens when B cells are activated?
They differentiate into effector and memory cells.
What are plasma cells?
The effector cells once Bcells have been activated
What does humoral immunity involve?
CD4 Th2 cells –> B cells and antibodies
What does cellular immunity involve?
CD4 Th1 cells –> macrophages
What is affinity maturation?
random mutations in v-region genes - changes to DNA sequence affecting affinity (antigen binding ability)
What is class switching?
Recombination of Ig gene segments. Constant region = heavy chains but change in variable region so there is the same antigen specificity
What are some of the chemical factors that are involved in vasodilation and increased vascular permeability in inflammation?
Histamine, NO, substanceP, bradykinin, leukotrienes, IL1, TNF, IFN-gamma
