Topic 2C Flashcards
Pathogens
Disease causing micro-organisms
Phagocytes engulf pathogens
Pathogens give off chemoattractants attracting phagocytes
Phagocyte engulfs pathogen forming a vesicles around the phagosome
Lysosome fuses with the phagosome digesting it
Digested material leaves via exocytosis
Phagocytes activate T-Cells
T helper cells have receptor proteins on the surface that bind to complementary antigens
Cytotoxic T cell activated them
Cytotoxic cells
Kill abnormal body cells
Produce perforin which makes holes in cell surface membrane making it freely permeable and killing it
Activated B-Cells
Covered in antibodies
Will meet antigen in the blood with complementary shape to antibody (antigen-antibody complex)
Antigen enters B cell via endocytosis and presented on surface when processed
Th binds to antigen and stimulate B cell divide to divide via mitosis
Clones formed (clonal selection) some become plasma cells and some memory cells
Plasma cells
Secret antibodies into blood plasma which are specific to the antigen (only survive for days)
Form antigen-antibody complexes
Only in immediate response
Antibody structure
Each antibody has unique tertiary structure due to amino acid structure 4 variable region Heavy chain Light chain Disulfide bridges
Cellular response
The t-class and other immune system cells they interact with eg phagocytes from cellular response
Humoral response
B cells clonal selection and the production of monoclonal antibodies from humoral response
Primary immune response
Happens when antigen first enters body
Slower as not many B-Cells to make antibody needed, enough eventually made to overcome infection but symptoms
T and B cells produce memory cells which stay in body. Remember antigen and antibody needed
Person is immune and have ability to respond quickly
Secondary Immune response
Same pathogen renters response quicker and stronger
Clonal selection happens faster. Memory B cells activated and divide into plasma cells that produce right antibody
Memory T cells activated and divide to correct type to kill cell carrying antigen
Happens before any symptoms
Antigenic variation
Some pathogens can change surface antigens
Active immunity
When your body produces it own antibodies after being stimulated by antigen
Natural- when you become immune after catching disease
Artificial- immune after getting a vaccine
Memory cells produced and long term protection
Passive immunity
Immunity from when you get antibodies made by a different organism, don’t produce your own antibodies
Natural - baby immune after recieving antibodies from mother
Artificial- get antibodies from someone else
Short term protection and immediate
Monoclonal antibodies
Antibodies produced from a single group of genetically identical B cells (plasma cells)
Cancer cells
Have tumour markers.
Monoclonal antibodies can be made to bind to tumour markers. Can attach anti cancer drugs to antibodies
Antibodies in contact with cancer cells bind to tumour markers meaning drug will accumulate around cancer cells
Pregnancy tests
Human chorionic gonadotropin (hCG)
Application area contain antibodies for hCG bound to AB1
Urine tracks up to the test zone where there’s more antibodies that are immobilised hCG sandwiched
If no hCG passed through to control zone
Indirect ELISA test
Uses antigens
Add sample, complementary antibodies will bind
Unbound antibodies washed out
Add secondary antibody thats bound to enzyme binding to the complex
Add substrate which stimulates a colour change
Direct ELISA test
Uses monoclonal antibodies
Add sample if complementary antigens present will bind
Wash out unbound antigens
Add complementary antibody bound to enzyme
Binding to enzyme
Add substrate stimulating colour change
HIV Structure
Core containing RNA and reverse transcriptase enzyme Capsid Matrix Phospholipid bilayer Attachment
HIV replication
Attachment protein attaches to CD4 protein T Cell
Caspid fuses with surface membrane, RNA and enzyme of HIV enter cell
Reverse transcriptase makes complementary strand of DNA from RNA template
New DNA injected into t helper cell nucleus using viral integrase
mRNA created using enzymes to make new viral proteins
mRNA passes out the nucleus through nuclear pore and uses protein synthesis mechanisms to make long chains of HIV proteins
HIV particle break away from T helper cell with piece of cell membrane around it.
Viral protease breaks up long chains and smaller chains combine to make mature virus and goes to infect other cells
Early symptoms of AIDS
Minor infections of mucous membranes (inside nose ear and genitals)
Recurring respiratory problems
Anti viral drugs
Target cutie specific enzymes eg reverse transcriptase
