Review of Immunology Pt. 1 Flashcards
The main role of the ____ is to prevent or reduce the severity of infections (whether they it is causes by bacteria , fungi, or parasites, such as protozoa and worms.)
Immune system
What is the first line of defense in the immune system?
Intact skin and Mucous membranes
Mouth, skin, eyes, secretions (lysozyme)
mucous membranes
What is second line of immune defense if microbe has breached mucous membranes?
Innate immune system
Non-specific destruction, rapid response. Components are fully formed and active. Preventative. Wide range.
Innate Immune
Skin, stomach acid, body temp, salinity
Examples of innate barriers
What is a neutrophils ability to engulf & ingest and subsequently destroy a microbe an example of (oxygen dependent)?
Innate immune reaction
Phagocytic leukocytes, antimicrobial proteins, inflammatory responses, fever are all what?
Second line of defense in innate immunity
-Lymphocytes
-Antibodies
-Memory Cells are all what
Specific defenses in adaptive immunity
Neutrophil & natural killer cells kill foreign cells without the need of specificity this is the an ____ characteristic
innate
What 2 things does the innate immunity NOT have?
- no improvement
- no memory
Keratin layer on ski, lysozyme, respiratory cilia, low pH, surface phagocytes, defenses, normal flora
ARE all what?
Factors limiting entry of microb INTO body (innate)
NK cells, Neutrophils, macrophages, dendritic cells, interferons, complement, transferring & lactoferrin, fever, inflammatory response,
are all what>
Factors limiting growth of microb (innate)
Two major function of innate hose defense?
- kill invaders
- Activate adaptive immune processes.
Disease where there is only innate immunity No adaptive, resulting in suffering from repeated life threatening infections.
Sever Combined Immunodeficiency disease (SCID)
Receptors found in innate immune system effectors that detect foreign molecular patterns.
They look at repeated lipoprotein, DNA structure, & protein structures.
Innate. Once they find PAMPS they trigger response.
Toll-Like Receptors
Common pathogen associated molecular patterns found in a great number of foreign microbes
PAMPS
CD14 on macrophages is co-receptor for TLR4, which can identify a specific PAMO found on LPS of outer membrane of gram - bacteria. This is an example of?
A toll like receptor recognizing a PAMP
NF-kB is a _________ that activates immune response gene which produces immune mediator to promote inflammation
nuclear transcription factor
TLRs can also mediate both acute and chronic ____
Inflmation
what are these?
Toll like receptors
Complement immunity
innate or adaptive?
Humoral or Cell mediated?
Innate + humoral
B-cells and antibodies?
innate or adaptive?
Humoral or Cell mediated?
Adaptive + humoral
Macrophages & NK cells
innate or adaptive?
Humoral or Cell mediated?
Innate + cell mediated
Helper T cells and cytotoxic T cells
innate or adaptive?
Humoral or Cell mediated?
Adaptive + cell mediated
Protein based response
Humoral response
Cell based
Cell mediated response
Highly specific reaction, takes several days to kick in due to required gene activation, improves following exposure, has memory!
Adaptive immune response
Main adaptive defense agains extracellular, encapsulated, pyogenic bacteria defense to neutralize toxins?
Humoral Immunity
What response would staph or strep get?
Humoral antibody response.
If the cytokines IL-4 & IL-5 are activated by they helper CD4 T-cell, what does this causes?
Take care of issue with Humoral response! Create antibodies.
If the cytokines Il-2 is activated by CD4- T-Cell what does this cause?
Cell mediated response!
main defense against intracellular microbes?
Cell mediated response!
What responds to intracellular bacteria like Mycobacterium Tb?
Cell mediated response, Helper T-cells & macrophages.
Nuclear transciritonal activator for CD4 T Helper cells
IL-2
Antibody or cell mediated?
Host defense agains infection (opsizinzation, neutralize toxins viruses)?
Humoral (antibody) mediated (b-cells)
Antibody or cell mediated?
Allergy (hypersensitivity type 1-3), ex. hay fever, anaphylactic shock
Humoral (antibody) mediated (b-cells)
Antibody or cell mediated?
Autoimmunity?
Humoral (antibody) mediated (b-cells)
Antibody or cell mediated?
Host defense agains infection (M. Tb, fungi, virus infected cells)
Cell-mediated (T-cells)
Antibody or cell mediated?
Allergy (type 4 hypersensitivity) ex. poison oak
Cell-mediated (T-cells)
Antibody or cell mediated?
Graft and tumor rejection
Cell-mediated (T-cells)
Antibody or cell mediated?
Regulation of antibody response (help/ suppression)
Cell-mediated (T-cells)
Antibody or cell mediated?
Regulation of antibody response (help/ suppression)
Cell-mediated (T-cells)
- neutralize toxins & viruses
- Opsonize bacteria
Two main function of antibodies
process by which the antibody immunoglobulin (IgG) and the C3b component of complement system both work to enhance phagocytosis
Opsinization
WHat?
inhibits organisms such as fungi, parasites, and certain intracellular bacteria such as Mycobacterium tuberculosis; it also kills virus-infected cells and tumor cells.
Cell mediated Immunity
What are 3 main elemelnts of cell and antibody mediated responses?
- Lots of diversity (antibody for everything)
- Long memory (Memory B & T cell) , second response faster than intial
- Very specific against antigens
What cells?
participate in both the innate and adaptive arms of the immune response.
THE BRIDGE
Macrophages & other phagocytic cells(dendritic cells)
What are the two funtions of macrophaes in innate (1) and adaptive (2)
- Innate; they phagocytosis and ingest various microbs no specificity
- Adaptive present antigens to helper T cells 1st. step of activattion of adaptive.
First responders, oxygen dependent killing, only innate. Great phagocytocers.
neutrophils
Antigen prensenting cells and conduct phagocytosis
Macrophages & Dendritic cells
VIruses attach to what protien on the surfaces of ONLY antigen presenting cells?
MCH, Dendritic Cells, B cells
MHC Class II
Microbe is broken down inside the macrophage and fragments of it called _____ appear on the surface of the macrophage, which they present on MHC Class II
Viral Epitopes
Viral epitopes on MHC Class II of Antigen presenting cells bind to what?
T-cell receptor on CD4+ T helper celll
**activated adaptive immue response **
What the CD4 helper T cell is initally activated, ____ is released which
2. Activates ______ cells
3. activates what phenomenea
IL-2 Released
1.Activates CD8+ Cytotoxic T cells
2.Clonol proliferation of self (CD4+ helper T Cells)
How do CD8+ Cytotoxic T cells become activated by IL-2 released from CD4 cells?
CD8+ Cytotoxic T cells contain an** IL-2 receptor** that binds the IL-2 singnal
How do CD8+ Cytotoxic T go on to kill invading cells following activation?
Cellular mediated immunity
They contain TCRs on surface that bind to viral epitopes and cause cell death
Release of what interlukins by CD4+ T helper cells results in the activation of B-cells?
IL-4 and IL-5
Once a B-cell is activated what two things can it go on to do?
- React with specific virus
- Differentiate into plasma cells which can class switch and produce and secrete antibodies
WHat are the 3 memory cells formed in the adapitve response pathway?
- Memory Th cell (CD4+ t-helper)
- Memory (CD8+ cytotoxic)
- Memory B cells
What is the first common step in initiation of immune response?
Macrophage injestion of foreign invader
making clones of that specific helper t-cell, some of which become memory helper t-cells.
important actiavtion step mediated by IL-2
Clonal Prolieration
viral envelope glycoproteins appear on the surface of the infected cells in association with what class of MHC?
MHC Class I
Cytotoxic t cells recognize viral anitgen on this and attack!
_______ of response is mediated by by the antigen recognizing ability of the T and B cells receptors
Specificity
Pathoway of acitvating B cells that is by peptide orgin (epitope )or anitgen
classical or T cell dependent pathway
Antigen pathway (ex. bacterial polysachrrides) of activaion of b-cells directly that is less regulated and pronounced response. IgM mediated. no IL 4 or 5 signals.
T cell INdependent pathway
What surface immunoglobuline allows for recognition of antigens?
IgM
A LOT of recognition
____ can also present antigen epitopes to CD4 Helper T cells using MHC II protiens
B cells
B cells can differentiate into what?
Plasma antibody producing cells
AN ____ mediated response is produced against one type of bacteria, but a ____ mediated response occurs in response to another type of bacteria.
- Antibody- one type bacteria
- Cell mediated another type
They can occur at same time
responders to an immune reaction inducing stimuli
Lymphoid cells
Give rise to lymphocytes
Lymphoid line then differentiates into either ____ or ___ lymphocytes enhanced by IL-7.
B or T
Stay Bone marrow, go to Thymus
T-cells in the thymus either become 1. or 2. ?
- CD4+ T helper
- CD8+ Cytotoxic T cell
B cells in the bone marrow can diffrentiate into what?
Plasma cells
Bone marrow stem cells become what cells?
Pro-B cells
Pro B cells can differentitate based on their receptor or tag.
What are two options?
- Pre-B cell receptor -> plasma cell
- CD56-> NK cell
B cell or T cell?
Antigen receptor recognizes only processed peptides in association with MHC protein
No whole unprocessed protien recognition!
T-cells
B cell or T cell?
Antigen receptor recognizes whole unprocessed proteins, and has no requirement for presentation by MHC protien
no need for processing
B-cell
____ lack any identifying surface proteins (CD 3, CD4 or CD 8)- CD means cluster of differentiation.** Before enteirng the thymys **
Pre-T cells
Once T cells pass through the ____ they express both CD protiens (CD2 on all + differentiator CD4 or CD8 or CD3
Through Thymus
T cells are double positive at first (contiain both CD4 and CD8) but what happne:
1. encounter MHC Class II =
2. encounter MHC Class I=
- encounter** MHC Class II = CD4+ **
- encounter **MHC Class I= CD8+ **
T-cells have a____ receptor
CD3 Receptor
B cells have _____ receptors= more range
Antigen recpetor
Where are cells that are either CD4 + or CD8+ Bearing receptors for self proteins are** killed by apoptosis**
clonal deletion
removal of cells that would not tolerate self proteins (i.e., they are inducing immune reaction against self proteins) which would result in **expansion of cells that are not attacking self proteins (self tolerance) **and prevent autoimmune reactions
negative selection process
A transciriptor regulator enhances the synthesis of this array of self proteins ( remember all cells have a full set of our genes).
autoimmune regulator (AIRE)
Main function of what
1) in the immune process as a receptacle for presenting antigens (which is essential in the activation of CD8 cells.
2) positive selection in the thymus.
MHC protiens
How to prepare MHC for organ donation and graftin?
Find very similar MHC Class I btwen donor and reciever, giver streiouds (reduce immunity).
Cell mediated immunity is affected. Therefore, patient will become more susceptible to other infections.
The ____ has its own immune system because of the vast amount of pathogens that enter the stomach.
gut-associated lymphoid tissue (GALT).
Gut
No thymus. Immune deficient and susptible to many infectios depsite having. IELS
DiGeorge’s syndrome
1. Remanent of thymus fuctional
2. Extrathymic tissue take over functio
40% of Lymphocytes are ____ they develop in a similar manner as to those that develop in the thymus
Intraepithelial lymphocytes (IELs) ,
B cells undergo _____ by apoptosis of cells that exhibit self antigen receptors, which also induces tolerance and reduces autoimmune diseases.
negative selection (clonal deletion)
*first have a chance to edit their receptors before (-) selection turns
B-cells edit out their receptors that are specific to self antigens (by using a different light chain in the receptor) which ultimately changes the specificity of the entire receptor and would** no longer recognize self proteins. **
Receptor editing
are large granular lymphocytes. No anitgen presentation requried, look for cells that lack MHC Class I protien on surface= infected= destroy cell.
NK cells
Stem from Myeloid precourssors, have MHC II protiens on surface. APC & Phagocytosis
Macrophages
Have extra arm, talk to MHC 2
CD4 T helper cell
Carried out by Th1 CD4 cells. Interlukin mediated cell response. Produce __
Produce IL-2
Carried out by Th-2 CD4 Helper cells, which help acitvate b cells. Produce __
IL-4 and IL-5
Activated by IL-12 which is from macrophages that have processed microbs
Naive th-0 which becomes Th-1
Cell mediated Response
Activated by IL-4 which is from from some human cell that has processed a microbe
TH-2 CD4 t cell
Humoral immunity
human cell that produces IL-4, which induces naïve helper T cells to become ____ cells
Th-2 cells
Th-2 cells production of IL-4 and IL-5 leads to
activation of B cells to become plasma cells (antibody immunity)
IL-12 from Th1 cells also ____ the production of Th2 cells, tipping the scale further towards Th1 response
Inhibits
Th1 = IL-12 (stimulatory) + Interferon (inhibitory)
Cell mediated response
IL-10 from Th-2 cellsinhibits IL-12 production by macrophages and drives the system toward a Th2 response
Inhibits
Th2 = IL-4 (stimulatory) + IL10 (inhibitory)
Humoral response