U1T2 - Keywords Flashcards
Immunity
Immunity
The action of the body’s immune system + how it deals with infectious diseases.
Antigen
Chemicals capable of producing a specific immune response. Molecule found on surface of living cells. Usually protein, may be nucleic acid/polysaccharide/inorganic molecule. All living cells have them. Self or non-self.
B Lymphocyte
If B cell receptors/genes stimulated, begins antibody mediated response. Formed from stem cells in bone marrow, mature in bone marrow, antibody mediated/humoral immunity. Produce antibodies in response to antigens due to bacterial/viral infection.
T Lymphocyte
If stimulated, begins cell mediated response. Divides into 4 types of T cell. Formed from stem cells in bone marrow, mature in thymus gland, cell mediated immunity. Respond to antigens attached to body cells (viral infection).
Antibody Mediated Response
Where B cell receptors stimulated so produces antibodies into blood stream + other body fluids. AKA humoral response.
Cell Mediated Response
If T cell stimulated by own body cells which have been changed by presence of non self material within them, directly destroys cell infected by pathogen. e.g. macrophages, viruses, cancer.
Antibody
Specifically shaped globular protein molecule, each responsible for dealing with specific pathogen (complementary to antigen).
Agglutination
Cells clumping together. 1st stage in allowing efficient phagocytosis by polymorphs. Allows engulfment + destruction by lysosomal digestion inside cell.
Clonal Expansion
Where stimulation of B cells results in cell division + production of new cells. e.g. clone plasma cells + clone memory cells.
Memory Cells
Clone cells which are specialised to fight a specific bacteria. Remain in circulation for years/life so secondary infection dealt with more quickly.
Memory T Cells
Circulate in body fluids. Rapid infection response for secondary infection.
Helper T Cells
Stimulates other immune cells (B cells), speeds up phagocytosis + secretes protein interferon to limit cell division.
Suppressor/Regulating T Cells
Stop immune response once invading cells destroys. Prevents autoimmune response.
Killer/Cytotoxic T Cells
Destroys infected cells by attaching to antigen on CSM + uses direct enzyme action.
Passive Immunity
Transfer of antibodies from 1 organism to another. Short term protection as antibodies eventually broken down.
Active Immunity
Own immune system being activated to produce antibodies. Long term immunity due to memory cells produced.
Natural Passive Immunity
Innate Immunity. Natural transfer of antibodies through placental transfer or colostral transfer.
Acquired Passive Immunity
Artificial injection of purified antibody (in serum) from blood of recovering patient/previously vaccinated animal.
Monoclonal Antibodies
Hybridising sensitised B cells from mouse which make required antibody (mouse inoculated with purified antigen) + lab grown cancerous cells. Hybrid cells grown continuously under optimum conditions so continuous antibody supply for medical applications.
Natural Active Immunity
Catching disease + creating memory cells so protected for life.
Artificial Active Immunity
Vaccines. e.g. Edward Jenner + smallpox. Attenuated/dead pathogens, isolated antigens + toxoids. e.g MMR, HPV, TB.
Attenuated
Purposely mutated.
Toxoids
Inactive toxins which still activate immune response.
Primary Immune Response
Triggered by body’s first contact with certain antigen (vaccine/pathogen encounter) No memory cells, slow response. Produce memory cells for future encounters.
Secondary Immune Response
Faster than primary as memory cells can be cloned rapidly (large concs of antibodies produced quickly for B cells) Disease symptoms may not even show as so quick.
Tissue Matching
Before organ donated, screened using HLA system. Determines genetic similarity in genes directly involved in antigen production. Fewer differences between donor + recipient HLA genes, more likely to be successful.
Immunosuppressant Drugs
After donation, recipient given cocktail of drugs to scale down action of immune system. Interfere with DNA replication of T + B cells so reduce number. Allows organ to function without major damage from immune system.
X-ray Irradiation
Radiation from x-rays can be targeted on bone marrow, resulting in recipient producing fewer immune cells (B + T)
HLA
Human Leucocyte Antigen
ABO system
Determined genetically. 4 groups. Based on antigens A + B (agglutinogens) 2 diff antibodies (agglutinins) a + b found in blood plasma. If a comes into contact with A, red blood cells carrying A agglutinate. Same deal with B + b. Example of polymorphism.
Agglutinate
When cells stick/clump together.
Rhesus blood grouping system
Involves rhesus factor/group D antigen. (group of antigens)
Rh positive
People who have rhesus factor antigens so are rhesus positive. (majority)
Rh negative
Don’t have rhesus factor antigens. Can have 1 transfusion of Rh positive blood with no complications as they have no antibodies against them. Sensitisation occurs. A second transfusion would cause agglutination + potentially death.
Sensitisation
When a person’s B cells make antibodies against rhesus factor antigens after a transfusion.
Haemolytic Disease
Massive destruction of child’s RBCs. Baby anaemic, short of breath (not enough O2 transport), jaundiced (breaks down haemoglobin producing other pigments).
Antibiotics
Group of chemicals which can kill bacteria. Many produced by other organisms as natural defence mechanism + have been purified for use as pharmaceuticals (penicillin)
Antibiotic Resistant Bacteria
Caused by genetic mutations in bacteria + overuse of antibiotics. Mutations inherited. Conditions then harder to treat if resistant.
ELISA
Enzyme Linked Immunosorbent Assay. Antibodies used to detect infection earlier or more accurately. Plastic plates with small circular wells on base with colour changing antibodies specific to certain antigens in them. If reaction between antibody + antigen in body fluid, enzyme activated + colour change detected. e.g. cancer, cardiac disease + pregnancy.
Cytokines
Group of small protein molecules which act as signals during an infection. Associated with T helper cells. Levels of certain cytokines in blood used as biomarkers for disease (TB, rheumatoid arthritis). Many promote inflammation which can help fight infection.
Non specific immune response
Not specific to individual types of pathogens. e.g. phagocytosis
Specific immune response
Distinguishes between individual pathogens + tailors response. Takes longer than non-specific but long term immunity. e.g. lymphocytes.
Inflammatory Response
Capillaries in affected area become leaky + allow plasma to seep into surrounding areas. Areas become swollen with pus. Appears red + feels hot due to increased blood flow + to help reduce infection by denaturing enzymes in pathogen.
Pus
Phagocytes, dead pathogens + cell debris.
Phagocytes
e.g. polymorphs (most common, arrive first) + macrophages (develops from monocytes, larger + live longer than poly). Can squeeze through capillary walls and engulf pathogens + surrounding cell debris at site of infection.
Phagocytosis
Phagocyte moves to pathogen as attraction by chemicals it produces, phagocyte membrane invaginates to enclose pathogen, pathogen engulf + membrane forms vesicle/phagosome around pathogen, lysosomes fuse with phagosome, hydrolytic enzymes in lysosome released into phagosome + hydrolyse pathogen. Soluble digested products absorbed into cytoplasm of phagocyte.
Macrophages
Engulfed + broken down pathogen + present some of pathogen’s antigens on own cell surface membrane.
Viral infected cells
Body cell invaded by virus. Some viral antigens presented on CSM of body cell.
Cancerous cells
Present abnormal antigens on CSM.
Serum
Blood plasma with all blood clotting substances removed.f
Herd Immunity
Concept that if high enough proportion of population vaccinated, those who not vaccinated less likely to catch disease (less likely to contact infected person). Important in protecting those who can’t be vaccinated (newborns + critically ill) + those who choose not to be vaccinated.
Polymorphism
A situation where there are several distinct categories or forms.
Epidemic
Diseases that spread rapidly through a small region (1 country) + affect higher proportion of population than normal.
Pandemic
Diseases affecting many thousands of people/several countries at once.
HIV
Disease causing virus. Those infected with it are called HIV positive. (produce antibodies to antigen of it) Probably mutated from SIV which causes same immunodeficiency in chimps. Transferred to humans in 1900s by bite/handling chimp meat.
AIDS
Syndrome of diseases associated with long term infection with HIV. Consequences of weakened immune system.
Virus reservoirs
Animals which harbour viruses that cause disease in humans. Suffer little harm from virus, not adapted to transfer pathogen (chance event)
Vectors
An organism that transmits disease.
Antimicrobial drugs
Drugs which are effective against broader range of microbes than antibiotics.
HCG
Human Chorionic Gonadotropin.
Self-tolerance
When immune system can recognise self and non self antigens so doesn’t attack its own body cells.
Immunoglobulin
Class of proteins present in serum + cells of immune system, which function as antibodies.
Pathogen
Bacteria, virus, or other microorganism that can cause disease.
Agglutinogens
Antigenic substance present in blood cells + bacteria which stimulates formation of agglutinin in blood serum.
Xenografts
Implantation of tissues from non-human species into humans.
Allografts
Tissue grafted from one individual to a genetically different individual of the same species.
Autografts
Tissue grafted from one part of body to another on same individual.
Isografts
Tissue grafted from one individual to genetically identical individual (twin)
IgE
Antibody against pollen. Causes release of histamine when pollen attaches to it.
Autoimmune Disease
Diseases caused by antibodies in patient attacking own tissues.
Agglutinin
Antibody found in blood plasma.
Agglutinogen
Antigen on CSM of cells.
