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53 Cards in this Set

  • Front
  • Back
Innate defense mechanism defination
-First line of defense
-These are non specific and inherited
Examples of innate defense mechanism
1 Physical barriers- Skin/mucous
2.Chemical barriers- Enzymes
3. Normal bacterial flora
4.Cellcommunication- Cytokines
5.Sensor system-Complements
7. Fever, inflammation
Adaptice defense mechanism defination
-Second line of defense- if the invader is able to overcome the first line
-These defenses are specific
What cells are involved in adaptive defense mechanism
1. B-lymphocytes
2. T-Lymphocytes
-Granulocyte-It is the most abundant and it contains phagocytes and degradative enzymes
Granulocyte-The least numerous and it is involved in allergic reactions and it releases histamine and heparin
-Granulocyte-Combat parasitic worm infection
Agranulocyte- Differentiate into two types of cells within the body tissue
1. Macrophages-phagocytes
2. Dendritic cells- Phagocytes
- They act as antigen-representing cells
T-cell functions
1. Cytotoxic T-cells
2. Helper T-cells
3. Suppressor T-cells
4. Memory T-cells
Natural Killer Cells
It is not specific and it uses pore-forming proteins (perforins) and proteases to kill cancer cells
Skin as a physical barrier
The epidermis posses a water-repelling protein called keratin whic makes the skin an arid environment
Which are the chemical defenses
2.Peroxidase enzymes
What is defensin
-They are short antimicrobial peptides found in mucus membrane and phagocytic cells.
-They insert themselves into bacterial cells membrane creating pores that disrupt the cell membrane integrity
- Enzymes that degrade peptidoglycan
- Its found in several body secreation including tears, saliva, mucus, perspiration, tissue fluid, blood and phagocytic granules
- They are very affective against gram + bacteria
What happens during inflammmation caused by complement activation
c3a and c5a increase permeability and act as phagocytes chemoattractants
What happens during foreign cell lysis
c5b, c6, c7, c8 and c9 aggregate within the membrane creating "holes"
What happens during opsonization
coating of c3b to the foreign particle making its easier for phagocytes to adhere to its its surface
Six steps of Phagocytosis
2.Adherance-surface receptors
3.Engulfment- Form phagosome
4.phagolygososome formation
5.Destructuction & dige enzyms
1. Coordinated response to invasion or damage
2. Results in dilation of small blood vessels, leakage of fluid and migration of white blood cells into tissue
3. Can be acute (scar tissue forms) or chronic (agranulomas)
This is a progammed cell death that can destroy infected cells without eliciting inflammation
It is caused by pryogens that act on the hypothalamus to increase body temperature
Two groups of pryogens that cause fever
1. Endogenous- Produced by host eg. Cytokins
2. Exogenous prygens- produced by invading microbe eg. Bacterial endotoxins
Adaptive immunity has three important aspects
1.antigen specific
2. tightly regulated & complex
3. Has memory
Two types of adaptive immunity
1. Cell Mediated
2. Antibody-mediated(humeral)
Steps of how Cell Mediated immunity works
1.Mediated by T-cell after and atigent had penetrated the non specific defenses
2. Antigen is taken up by antigen presenting cells and broken down
3. The fragments merge with histocompatability complex proteins on the APC's membrane
4.T-cell comes into contact with the APC and recognized the new MHC protein and becomes active
5.Activation of t cells dive and differentiate
Cytotoxic T-cells -CD8
-Induce apoptosis in infected cell or cancer cells and:
a. release perforin to rupture membrane
b. Secrete proteases that induce death
2. produce cytokins that activate neighbouring cells
Helper T-cells - CD4
-Release cytokines that activate T-cells, B-cells, natural killer cells and phagocytes
Memory T-cells
They recognize specific antigen in case of repeated exposure
Overview of antibody-mediated immunity

Plasma cells?
Memory b-cells
1. Helper T-cells stimulate B-cells division and differentiation
antibodies involved
- Secrete antobodies
-Long lived
Variable regions (Fab)
Constant regions (Fc)
- cointain antigen bidning sites and form antigen-antibody complex
- Bind other cells of immune systems
Five classes of Antibodies
1.Produced-Primary response
2.Produced-secondary response
3.Secreted-mucous membrane
4.Found-basophils and mast cel
causes allerfic reaction
Antibody inactivates antigen by?
3.agglutination of antigens
5.complement activation
6.antobody-dependent cellular cytotoxicity
secondary lymphoid organs
1. sites where lumphocytes gather
2. Lymph nodes, spleen, tonsils, adenoids, appendix
Primary Lymphoid organs
1.Where lymphocytes originate and mature
2. Bone marrow and thymus
The practice of deliberately stimulating the immune system in order to protect individuals against a disease
Herd immunity
-The inability of an infection to spread because of the lack of susceptible hosts
Types of immunity
1.Naturally acquired
2.Artificially acquired
3.Active immunity
Natural acquired immmunity
Passive immunity
active immunity
-Exposure to infectious agents
-getting over chicken pox
-mother-child through breast milk
Artificially acquired immunity
passive immunity
Active immunity
-Via non natural means
-from one patient to another
-via injection immunization of childeren for measles is an example
a preparation of living or inactive microoganisms, viruses or their components used to induce active immunity
Types of vaccine
1. Attenuated vaccines
2. Inactivated vaccines
Attenuated vaccines
are weakened form of the disease-causing agents -alive
Inacticated caccines
forms that are unable to replicate but still cause an immune respomse-dead
Three types of inactivated vaccines
1. Toxids
3.Polysaccharide vaccines
protein subunit vaccines
Polysaccharide vaccines
- in activated toxins -Diphtheria and tetanus

- Composed of key protein antigens of the infectious agnet rather than the whole cell- heppatitis B vaccine

- Composed of the polysaccharides that make up the capsule of certain microoganisms- streptococcus pheumoniae vaccine
Use of serum antibodies to detect and identify antigens or concersely, use of known antigen to detect antibodies
Measure of the amount of specific antibody in serum amd a rise in titer of antibodies suggest an active infections
What can mmunosorbent Assay ELISA test
detection of HIV
How does ELISA test's work
1. Antigen is attracted to plasitic wells
2. The serum to be tested is added and incubated.
3. If the antibodies are present they will bind to the antigen
4. To detect if antigen-antibody reaction had occured, anti-HGG is added
5.The anti-HGG reacts with any bound antibodies and the excess is washed away
6. Chromogen is added and a colored end product is produced if antibodies were present
Precipitation and aggrutination reactions
- Antibodies combine with soluble antigens to form a visible insoluble precipitate- antibody- antigen complex
Immunoflourescent dyes
attached to known antobodies and them used to detect antigens