Immune System Flashcards
What is innate immunity?
present at birth and passed down genetically from the parents to children
Those were Ab’s originally created by the parent after fighting an infection
What is adaptive/specific immunity? 2 parts?
Response to a specific antigen => requires identification through memory cells
Cell-mediated immune system (T+B lymphos, monos, macros, dendrites, macros, etc)
Humoral immune system => Abs
What is passive immunity?
Transferring active humoral immunity in form of already made Abs either naturally (maternal=>placenta) or artificially when high levels of human Abs specific for a pathogen/toxin are transferred to non-immune individuals
=> short term
Def. of antigen?
Antibody generator => when induced stimulates production of Ab
=> can initiate CMI/humoral
Ag’s: Toxins, bacteria, foreign blood cells etc
What is an epitope?
Specific structural element on surface of the antigen recognized by a specific Ab
Greatest challenge of immune system?
Identify pathogen from self
What is clonal selection theory?
Born with vast variety of diff lympho’s based on genetic combination in early cell development
=> can react to Ag even for first ever encounter => proliferate/clone/mature for next time
Structure of IgX/Ab ? Which part binds to epitope of Ag ?
2 heavy chains/2 light chains bond by hydrophilic/phobic forces/disulfide bonds
Fc bind to pathogen
Fab binds to Ag(epitope)
What is opsonization?
Way of identification
=> Ab recognition/binding to bacteria, covering it
=> complement activation => bacterial lysis
Know structure/pic of all Immunoglob./Ab’s
K
Where is IgA found? What is special about it?
Dimer
15% of total
J chain marks it for secretion
Protects IgA from proteases <= secretory component
Secreted by B lympho’s in mucosal lining
IgD why is it special? Location?
Monomer Produced by plasma cells (B lympho) 1% Co-expressed with IgM Can activate B lymphos, baso,mast cells
IgE? Involved in? Structure? Abundance? Etc
Produced by plasma cells (B)
Involved in type 1 hypersensitivity allergic reaction and response to parasitic worms/protozoans
=> bind to Fc receptors found on surface of mast cells/basos
Least abundant
Most abundant IgG? Found where? Involved in? Special how?
Monomer
Produced by plasma cells/B lympho
Involved in types II and III hypersensitivity reactions and helps induce phagocytosis
=> only appears when prior infection happened (IgM) => 24-48h after Ag stimulation (time dependent)
Which Igs are found in human colostrum?
IgA most
IgG a lot too
IgM: structure/special/found where?
Large pentamer produced by plasma cells (B)
=> first Ab to appear
Spleen production, found in blood => blood type determination
What is hematopoiesis?
Formation of blood cellular components
All blood cells are produced from? Then differentiate by?
Haemotopoietic stem cell
=> common lymphoid progenitor =>lympho’s/plasma/dendritic
=> common myeloid progenitor =>Thrombo/Ery/Granulo=baso/neutro/eosino/mast cell
Types of lymphocytes?
B
T
Types of T cells?
Cytotoxic CD8 Th1 Th2 Suppressor T Memory T
Types of B cells?
Plasma cells
Memory B cells
MHC function?
MHC acts as extracellular indicator of proper or dysfunctional intracellular protein balance
Function of class I MHC? Type of source?
Help mediate cellular immunity to address intracellular pathogens, such as viruses or destruction of malignant host cells
Endogenous source
=> recognized by CD8 coreceptor on Tc (=CTLs) or NKs
Class II MHC function?
Happens only on designated APCs (=macrophages, B cells, Dendrite cells) based on exogenous sources
=> TCR of naive helper T cells (Th0) has CD4 (cluster of differentiation 4) coreceptor that recognizes MHC II
What causes Abs to be produced?
B-cell with MHCII binds to Th0
=> B cell secrets Ig’s
Tc having CD8 recognize which type of MHC? On what kind of cells?
MHC I
Nucleated cells = not RBCs
Th cells having CD4 coreceptor recognize which MHC type? On what cell?
MHC II
=> APC
What is an APC?
Macrophage
DCs
Some B cells
How are pathogens processed inside the infected cell?
Host cell => present to T cell
Internal pathogen => digested into peptides by proteosome
=> taken up by TAP transporters (transporter associated with antigen processing) found in ER
=> into vesicles => cell surface => associate with MHC-I
How are pathogens processed outside a cell?
Taken up by specialized APCs => digest in lysosomes/proteasomes => peptide fragments => coupled with MHC class depending on size and moved to surface
=> express MHC-II (up to 14AA long)=>CD4=>Th
OR
=> express MHC-I (<8 AA long)
What activates MHC?
Binding of TCR to specific Ag-MHC complex => MHC signalling activated
First step of MHC activation? What is the goal?
Leukocyte-specific tyrosine kinase (LcK) with sarcoma homology domain binds cytoplasmic tail of CD4/8
=>=>=> altered gene expression=> T cell degranulation => Tc releases cytokines
Function of B-lympho in humoral immunity?
Differentiate into plasma cell upon Th2 activation => produce Ig’s
Function of Th cell?
Function in cell mediated immunity.
APC ingests antigen => presents to Th0 => differentiates into Th1/2