Adaptive vs innate Flashcards
How do we get innate immunity
It is present before exposure to any pathogens. Born with it
How do we get acquired immunity
Develops after exposure to agents such as microbes, toxins, or other foreign substances. Very specific response to pathogens
Types of innate defenses in vertebrates
Barrier defenses, phagocytosis, antimicrobial peptides
Barrier defenses
Include the skin and mucous membranes of the respiratory, urinary, and reproductive tracts
Role of mucous in barrier defenses
Allow for the removal of microbes
Role of body fluids (and types of fluids)
They are hostile to microbes (saliva, mucus, and tears)
Role of skin and the digestive system
Has low pH, prevents the growth of many bacteria
Cells that recognize pathogens in the mammal body
Phagocytic cells
How do phagocytic cells recognize pathogens
TLR (toll like receptors)
What do TLRs recognize
Fragments of molecules characteristic of a set of pathogens
Types of phagocytic cells in the mammilian body
Neutrophils, eosinophils, dentritic cells and macrophages
Neutrophils
engulf and destroy pathogens
Dentritic cells
Stimulate development of adaptive immunity
Eosinophils
Discharge destructive enzymes
Job of natural killer cells in innate immunity
Circulate through the body and detect abnormal cells and release chemicals that lead to cell death
System involved in many cellular innate defenses
Lymphatic system
How do peptides and proteins function in innate defense
By attacking pathogens or impeding their reproduction
Type of antimicrobial protein
Interferon
Interferon
Proteins that provide innate defense, interfering with viruses and helping activate macrophages
How many proteins make up the complement system and what do they cause
- They cause lysis of invading cells and help trigger inflammation
How is the inflammatory response brought about
Brought about by molecules released upon injury or infection
Mast cell
A type of connective tissue, release histamine which triggers blood vessels to dialate and become more permeable
What type of cells release cytokines
Macrophages and neutrophils (activated)
Cytokines
Signalling molecules that enhance the immune system
What does the delivery of antimicrobial peptides result in
The accumulation of pus (a fluid rich in white blood cells, dead pathogens, and cell debris from damaged tissues)
Fever
A systemic inflammatory response triggered by substances released by macrophages in response to certain pathogens
Septic shock
A life threatening condition caused by an overwhelming inflammatory response
Adaptive immunity
Adapts as we grow
Antigen
Any substance that elicits an immune response
What cells bind to an antigen via antigen receptors specific to part of one molecule of that pathogen
T or B cells
Epitope
The small accessible part of an antigen that binds to an antigen receptor (specificity)
T vs B cells
Have similar components but encounter antigens in different ways
Structure of the B cell
Y-shaped molecule with two identical heavy chains and two identical light chains
What do variable regions of the B cell chains do
Provide antigen specificity
Constant regions of chains and variable regions
Constant regions vary little among B cells while variable regions differ greatly
What does the activation of a B cell from binding to an antigen give rise to
Cells that secrete a soluble form of protein called an antibody or immunoglobulin
Structure of antibodies
Y-shaped, secreted and not membrane bound
B cells are considered (humoral or cell mediated)
Humoral
T cells are considered (humoral or cell mediated)
Cell mediated
T cell structure
Two different polypeptide chains called alpha and beta
-Tip of the chain is variable region and the rest is the constant region
What do T cells bind to
Antigen fragments (MHC) displayed or presented on the host cell
Antigen fragments bound to the cell surface proteins
MHC molecules
MHC
Major histocompatibility complex
Host proteins that display the antigen fragments on the cell surface
Antigen presentation
In infected cells, MHC molecules bind and transport antigen fragments to the cell’s surface
What two things can T cells bind to
MHC molecule and antigen fragment
B cell vs T cell
B cell: Humoral immunity. Can connect to antigens right on the surface of the invading pathogen or bacteria
T cell: cell mediated immunity. Can only connect to virus antigens on the outside of infected cells
