Flashcards in Basics of Immunology Deck (127)
Pathogen-associated molecular patterns. On the intruder,. What is recongnized by PRRs on the cell surface of innate immune cells. These are proteins that humans don't have, so we know they don't belong (ie a protein of bacterial cell well or dsRNA)
Pattern-recognition receptor. Proteins on the cell surface expressed by cells of innate immune system. PRRs identify the PAMPs expressed on foreign intruders
Toll-like receptors. A type of PRR. There are at least 10 TLRs and are located where infections enter, ie lining blood vessels
Damage-associated molecular pattern. Stress or damage indicators expressed by body cells (ie paintball example)
What are some foreign patters recognized by TLRs?
TLR1: Lipopeptide (bacterial)
TLR2: Zymosan (fungal)
TLR3: dsRNA (viral)
TLR5: flagellin (bacteria)
TLR6: Lipopeptide (mycoplasma)
TLR7: ssRNA (Influenza)
TLR8: ssRNA (viral)
TLR9: Unmethylated CpG (herpes)
TLR10: asthma connection
What is the final transcription factor that is most commonly activated by inflammation?
Bad bug makes endotoxin >> endotoxin is recognized by TLR >> Signal cascade >> Activates NF-KB >> Inflammation
Made by PAMP-stimulated cells. Small cell-signaling protein molecules that are secreted by the immune system for intercellular communication Helps inflammation
Made by PAMP-stimulated cells. Family of small cytokines. Induce directed chemotaxis of WBC to site of injury.
Innate to Adaptive Immune Response
At the wound site, immature DCs get activated by the cytokines and chemokines secreted by the innate immune response, and they take up anything they can find. Activated (mature) DCs leave the local wound and travel to the nearest lymph node. They "show" the antigen they have eaten to the lymphocytes, and the adaptive immune response develops with T cells, B cells and DCs.
Phagocytic cells at the interfaces between the body and the world (skin, lung, mucous membranes...). Immature DCs are the best phagocyte ever! Mature DCs are the best antigen presenting cell ever! (A change in phenotype occurs when the DC matures)
Start development in bone marrow, but mature in THYMUS. (Helper) T lymphocytes recognize and remove foreign substances. Two main classes: Helper T cells and Killer T cells.
The epic journey of Helper T Cells
They recognize antigens using surface receptors which see antigens presented by the DC that is traveling via lymphatics. When the HTC recognizes the foreign material it becomes activated and proliferates. The daughter cells travel through the body until they reach where the antigen first invaded. There they are re-stimulated and release short-range mediators called lymphokines. These mediators call up much of the inflammatory response, attracting monocytes/macrophages
Killer T Cells
Kill any body cell that they identify as containing abnormal molecules. Examine surface of incoming DCs, but they are also looking for fragments on MHC Class I antigen presenter, which are on ALL cells. Appropriate clones of Killer T cells proliferate and daughter cells circulate. When a daughter cell binds a cell showing the same peptide it delivers a lethal "hit" signaling the target cell to commit suicide.
The role of B cells in immunity
Recognize and remove foreign substances and protect extracellular spaces of the body by releasing antibodies into tissue fluids, blood, and bodily secretions. They arrange for phagocytosis and recognize antigens via surface receptors and become activated and proliferate. They do NOT require recognition of MHC. Fully differentiated B cells are called plasma cells and are antibody producing "factories"
What are the 5 immunoglobulin classes?
IgG, IgM, IgD, IgA, IgE
most abundant antibody, 2 adjacent IgG molecules binding an antigen cooperate to activate COMPLEMENT. It is the only antibody that passes from mother to fetus. Phagocytic cells have receptors for the Fc of bound IgG>Opsonizing
A system of proteins that enhances inflammation and pathogen destruction
Even better at activating COMPLEMENT than IgG. First antibody to appear in blood after exposure to new antigen. Replaced by IgG in 1-2 weeks. It is the ONLY antibody made in the fetus.
Antibody inserted into B cell membranes as their antigen receptor
Most important antibody in secretions (tears, saliva, breast milk). Associated with SECRETORY COMPONANT which makes the antibody resistant to digestive enzymes and plays a role as the first line of defense against microorganisms
Resistance to parasites and worms. Fc attaches to mast cells in tissues. Once attached, when it encounters and antigen it will cause the mast cell to make protaglandins, leukotrienes and cytokines and release its granules which contain mediators of inflammation (ie histamine). Also triggers Mast Cells to release Eosinophils to combat parasites
Type I immunopathology
Immediate hypersensitivity. Patient makes too much IgE to environmental antigen
Type II Immunopathology
Autoimmunity due to antibodies that react against self. Treat diseases with immunosuppressives
Type III Immunopathology
Patient makes antibody against a soluble antigen. Antigen-antibody complex sometimes gets trapped in basement membrane of capillaries, where they activate Complement causing inflammation. (ie Systemic Lupus Erythemtosus and Rheumatoid Arthritis) Also, large doses of penicillin can cause Type III
T-cell mediated. Can be autoimmune or innocent bystander disease. Example: in TB most of the cavity formation in lungs is T cell mediated, not bacterium mediated
HIV infection of TH cells; binds to CD4 molecules they have on their surface. Uses reverse transcriptase to insert itself into the cells genome, where it remains latent until T cell is activated, leading to loss of TH cells
Chronic frustrated immune response
Antigen is not to "self", but something you can't get rid of, like gut bacteria or gluten
Nucleated cells of the blood, white blood cells. The buffy coat when you centrefuge blood
Leukocytes whose nucleus has a smooth outline; monocytes and lymphocytes