Immune system Flashcards
Non self cells example
Pathogens
First line defense and what happens of pathogens get there first
Physical, chemical, and mechanical barriers.
If pathogens get there first, nxt step is
1) detection and identification of pathogen
2) communication w/ other immune cells
3)recruitment/coordination of response
4) destruction of pathogen
2 divisions of immune system response: innate immunity
Rapid acting (mins-hrs)
Non specific
(Acts on anything non self)
Involves barriers to pathogens (chemical,phy, etc)
Cellular response that directly destroys pathogen
Characterized by inflammation
Non memory cells- not remembered by immune system
2 divisions of immune system response: adaptive immunity
Slow, specific, long lasting (memory cells)
Learned response to a specific pathogen/antigen
Cell mediated immunity vs antibody mediated (humoral) immunity
Contact dependent signalling (cytotoxic T-cells)
Production of antibody (B lymphocytes and plasma cells)
Primary and secondary lymphoid tissue
Where wbc are produced
1)thymus gland (where leukocytes produce-wbc)
2) bone marrow (all other wbc)
Where wbc mature
1) spleen- monitors blood exposed to active immune cells
2)lymph nodes- like spleen, also monitor blood and isf
3) MALT- diffuse lymphoid tissue lining digestive, respiratory, tracts, etc
Innate immunity- physical barriers
Skin
Hair (filters)
Mucus membrane (lines all body cavities/tracts that open to outside of body)
Innate immunity- mechanical barriers
Involves flushing mechanisms
Flow of tears/urine (removes microbes/debris)
Coughing/sneezing (blows put irritants)
Mucocilary escalator- cilia and trachea pushes mucus with trapped microbes/debris frim lungs towards pharnx
innate immunity- chemical barriers
- ph acidity (microbes cant stand)
2.enzymes
3.antibodies
ex: Iga antibodies bind to pathogens, clump them together and mark them for - complement system (most imp is C3 and C3b.
cascade of over 30 proteins that result in phagocytosis
complement system components:
(chemical barrier)
activation of inflammation via mast cells
opsonization- flagging of bacteria via C3b
complement proteins act as chemotoxins (chemicals that attract cells) which helps to direct phagocytosis towards invading pathogens
complement activation: classic pathway
requires that an adaptive immune response has occured
it’s triggered when an antibody binds to an antigen, such as on the surface of a bacterial cell
complement activation: alternative pathway
completely innate
carbohydrates in pathogen surface directly activate formation of C3 and C3b
complement activation: results of both pathways (alternative and classic)
c3b flags/marks pathogens for phagocytes
C3b converted into C5b results in pores in microbe cell to let na and water to enter cell. result= rupture of cell
byproducts of C3b and C3b activate what
leukocytes (wbc) involved in inflammatory response (mast cells, basophils)
mechanism of action when virus enters cell
1) viral rna enters cell
2)viruses use host cell for replication
3) viruses cause host cell to produce interferon a and b
4)interferon a and b are released from infected host cell and triggers production of AVP
when virus tries to infect cells, w/ avp’s, viral replication is blocked
when are antiviral proteins (AVP) inactivated
when host cell not infected
innate immunity: normal flora
skin microbiome- commensal (friendly) bacteria on skin surface act to:
a) breakdown sebum which releases FA that contribute to low ph of skin surface (not good)
gut microbiome- commensal (friendly) bacteria act to:
Outcompete harmful microbes
Reinforces tight junctions for protects and maintains physical barrier
Promote production of antimicrobial peptides
Innate immunity: what cells is involved in cellular barriers
Includes all immune cells except T and B lymphocytes
Only involved in the innate immune response
phagocytes function in innate immunity and adaptive immunity
1) remove dead/dying cells, debris, old rbc, digest pathogen, etc
2) act as antigen presenting cells
dendritic cells function in innate immunity and adaptive immunity
1) non specific ingest and digest pathogens
2) act as antigen presenting cells
O2 dv vs iv phagocytosis
Oxygen-dependent: Uses reactive oxygen species to kill pathogens.
Oxygen-independent: Uses enzymes (e.g., lysozyme, acid hydrolases) and antimicrobial peptides to destroy pathogens without relying on oxygen.
NKCs natural killer cells
Innate- non specific
Kills any cell that lacks MHC-1 (- healthy cells=has lots of these). To kill they release perforin (forms pores) or release grabzyme B (initiates apoptosis- cell death)
Rubor, calor, tumor, dolar
Redness, hear, swelling, pain
adaptive immunity
2nd line of defense, highly specific, long lasting resistance to pathogens, if first line defense go wrong (barriers) creates antibodies/cells and have memory cells
adaptive immunity cells: T lymphocytes (3 types)
helper T cells: regulates immune response
cytotoxic T cells: once activated, attacks/destroys virus infected cells that have the specific antigen
regulatory T cells (T reg): prevent excessive immune responses by suppressing other lymphocytes
adaptive immunity cells: B lymphocytes (and types)
naive cells that get exposed to antigen creating a primary immune response. when it encounters that antigen again, secondary responses occur
a) memory cells
b)plasma cells (cell that produces antibody)
antibodies
Y shape, each arm consist one light chain and one heavy (chains gives them their specificity- diff)
antibodies types and overall function (MEAGD)
IgM
IgG- (plasma antibodies)
IgE- binds to mast cells, protects from parasites
IgA- found in secretions of resp, digestive, sweat, urinary, etc
IgD- found on surface if B-cells
overall function: bind to antigen to remove/inactivate- lead to b-cell production (results in more antibody production), lysis, etc.
2 categories of humoral immunity: active vs passive immunity
1) body exposed to pathogen produces its own antibodies via humoral response
(natural, ex: preson ill and then recovers or artificail ex: vaccine)
2) the. body aqu antibodies made by another individual/ organism (horses, sheep, etc)
natural= antibody pass from mother to fetus accross placenta or breast milk
artificial= injections containing antibodies ex: snake bite or post exposed injections for rabies, etc.
