Immunology Flashcards
Immunity
Resistance to infectious agents
Immune system
The collection of cells, tissues, and molecules that mediate resistance to infection
Immune response
The coordinated reaction of these cells and molecules to an infectious agent {antigen}
Antigen
Infectious agent
Immune response
Coordinated response of immune cells
Functions of immune system
- Defense against infections
- Recognizing and responding to tissue grants and newly introduced proteins
- Defense against tumors
Low immunity
More susceptible to infections
Shown by aids
Aids
Acquired immune deficiency system
- knocks out immune system
Vaccinations
Immune system primers and activators, made of non- infectious part of an organism
Effective because they stimulate an immune response to microbes and prone the immune system for a potential infection by that microbe
Have eradication’s some infectious diseases
Protective immunity
Made by 2 parts of the immune system
1. Innate immunity
- Adaptive immunity
Innate immunity
Mediates the initial protection against infectious agents
INATE - always there; born with it
Is there 1-12 hours from start of infection
Adaptive immunity
Develops more slowly and mediates the long term, more effective defense against infectious agents
Once is functional, much more long lasting, selective, and stronger
Takes days to start
Innate immune system parts
Order of starting goes down: Epithelial barriers Phagocytic cells NK cells Proteins in complement pathway
Epithelial barriers
Skin or Any other epithelia
Adaptive immunity parts
B and T lymphocytes and products - antibodies (made by B cells)
Adaptive immunity types
Humoral
Cell mediated
Humoral
Provides defense against extracellular microbes or foreign particles
Things outside cells,
Done by B cells - they make. Antibodies to target these
Cell - mediated
Defense against intracellular microbes
Something that affects the cells ( either intracellular microbes or phagocytized microbes - bacteria)
T cells
T cells
Kill the affected cells so it cant spread infection
Helper T cells
Active other cells, like macrophages and B cells so that they do their jobs
Cytolytic t tell
Binds of affected cell so you can kill it
Properties of the adaptive immune system
It is specific - specific antigens elicit a specific response
Diverse - enable immune system to respond to a wide variety of antigens
Memory - leaves to enhanced response to repeated exposures to the same antigen
Memory
Demonstrated by the production of a second reponse. To antigen c by
Primary immune response
Takes a little while to occur Activate anti-X B cells Make ab And you fight it off Left with memory B cells that do not have to go through activation process from beginning ; so next time faster and stronger response
Specificity and diversity of adaptive immune response
Memory cells - for only influenza Second time Influenza and diphtheria Strong response to influenza Primary to diphtheria Responding against 2 different agents at same time
Clonal selection
Each lymphocyte can recognize one specific antigen
May never encounter antigen - go apoptosis and die
If encounters it - makes hundreds of thousands of more cells to fight it - ie. Multiply
Phases of adaptive immune response
- Recognition : recognizes antigen
- Activation : clonal selection (peaks day 7)
- Effector : action is happening [ humoral and cell mediated]
- Decline/ contraction : after fought antigen off , then cells undergo apoptosis , decline in number of cells
Day 14 contraction starts - homeostasis
- Memory : surviving antigen - specific cells
Effector cells
Activated cells of adaptive immunity
Lymphocytes
B cells : humoral
T cells : cell- mediated
NK. Cells : innate immunity
Antigen presenting cells
These cells can recognize antigen directly , T cells and B cells cannot
Phagocyte cells and then present it - T and B cels need these
Dendritic cells : initiate T cells
Macrophages: initiation and effector phase of cell mediated
Follicular dendritic cells : display antigens to B cells
Effector cells types
T cells
Macrophages
Granulocytes - neutrophils, eosinophils, basophils , B cells
Active immune cells, actively carrying out function of immune cells
B cells
Make ab
Ab neutralize the antigen
Regulatory T cell
Stop potential auto immune reactions
Prevent to harm own normal tissues
NK
Kill infected cells like cytotoxic T cells
Maturation of lymphocytes
All immune cells start from stem cells in bone marrow
Then primary generative lymphoid organs where the B cells and T cells mature
B cells stay in bone marrow
T cells go to thymus
Then go out of organ, mature, but still naive.
Naive until encounter and antigen - note from primary go to secondary peripheral lymphoid organs [ lymph nodes, spleen, mucosa/ cutaneous lymphoid tissues]
NOTE: can travel in lymph or blood
—— wher lymphocytes will encounter antigen on their first try; do not float around waiting for antigen
Once activated no longer naive
Now leave secondary organ and seek out target
Spleen
2 regions
- one hold B cells [follicle] - on far ends in groups
- one hold T cells [PALS - periarteriolar lymphoid sheath] - sorround blood branch in middle
Lymph nodes
Senate areas of B cells and T cells
- B cells : follicle [ periphery ]
- t cells : paracortex [region around the cortex]
NOTE: single antigen can activate both T and B cells
Other lymphoid organs
Tonsils Adenoids Appendix Bone marrow Gut associated lymphoid tissue
Specialization
Generates responses that are optimal for dense against different types of microbes
Bone marrow
Origin of all blood cells
Maturation of B cells
Thymus
Secrete thymosin
Maturation of T cells
Spleen
Exchanges lymphocytes with blood
Resident lymphocytes make abs and activated T cells
Resident macrophages - remove microbes, debri, old RBCs from blood
Stores small amount of rbcs, that can be added to blood by splenic contraction
