43 Flashcards
pathogen
agent that cause disease infect a wide range of animals
innate immunity
all animals
rapid
barrier defence:
- skin
- mucus
- secretions
internal defence:
- pathogenic cells
- natural killer cells
- antimicrobial proteins
- inflammatory response
Adaptive immunity
vertebrates
slower
Humoral responce:
-antibodies in body fluid
Cell-mediated responce:
-cytotoxic defend
innate immunity of invertebrate
- exoskeleton of insects
- lysozyme in digestive system
- phagocyte in hemocyte
- antimicrobial peptides secreted by hemocyte disrupting plasma membrane
- recognize by structure in their cells
innate immune of vertebrate
barrier defence phagocytosis natural killer cells antimicrobial peptides interferons inflammatory response
Barrier defence
skin
mucus
body fluids
low PH of skin and digestive system
phagocytic cells
cellular innate defence
recognize pathogens by TLRs ( troll-like receptors)
- neutrophils: engulf and destroy pathogens
- macrophages; everywhere
- Dendritic cells: stimulate development of adaptive immunity
- Eosinophils : enzymes, beneath mucosal surface,
natural killer cells
detect abnormal cell
viral and cancerous cells
release perforin
exporuse to Calcium
turn from spherical to cylindrical
stick together
fuse with plasma membrane
create pores
target bursts
Dendritic cells
go from interstitial fluid to lymph after encountering pathogens
stimulus adaptive imuune
antimicrobial peptides
protein
impend their reproductive system
complement system
30 protein, membrane attack that form spores in bacterial cells
interferon
interferon interfering with virus and help macrophages –> makes other cells immune
inflammatory responses
mast cell release histamine
macrophage release cytokines
dilate blood vessel
attract neutrophils
neutrophils digest pathogens and tissue heal
systemic triggered by pyrogens released by macrophages and by toxins from pathogens
Septic shock
a life-threatening condition caused by an overwhelming inflammatory response
Adaptive response
Lymphocyte
T cell : thymus
B cell : bone marrow
Antigen
substances that can elicit a response from B & T cell
each B & T cell is specific for particular epitope of antigen
B cells
Y- shaped receptors
2 identical heavy chains and 2 identical light chains
variable regions provide the specificity
B cells recognition
Binding of a B cell antigen receptor to an antigen
secretion of soluble protein –>antibody/ommunoglobulin which lack the anchor receptor in plasma membrane
T cells
receptor consist of 2 different polypeptide chains ( ALPHA & BETA )
T cells recognition
antigen transportation:
antigen fragment bind to MHC molecule
transported to cell sruface
Tcell combine with it
characteristic of adaptive immune system
- diversity of lymphocyte and receptor
- self-tolerance : lack of reactivity against own cell
- B&T cell proliferate after activation
- immunological memory
Clonal selection
antigen bind to receptor
cell proliferate into a colony
some daughter cell develop into memory cell
others into effector cell called plasma cells that secrete specific antibody
Helper T cell
trigger both Humoral and cell-mediated immune response
Antigen-presenting cells
class I & II MHC molecules
class II MHC: based upon which antigen-presenting cells recognized
Cytotoxic T cells
Response to Infected Cells
effector cells
recognize fragments of foreign proteins produced by infected cells
have an accessory pr that binds to class I MHC
secrete perforin that destroys cell emmebrane
B Cells and Antibodies
A Response to Extracellular Pathogens
Activation :B cells and helper T cells and proteins on surface of pathogens
In response to cytokines from helper T cells and an antigen, a B cell proliferates and differentiates into memory B cells and plasma cells
Antibody Function
mark pathogens for destruction
