Immunology Flashcards
Types of cell that stimulate an immune response
Pathogens
Toxins
Abnormal body cells
Cells from other organisms such as transplants
Antigen
a molecule usually a protein stimulates an immune response that results in the production of a specific antibody.
Phagocytosis
Chemical attracts phagocyte to area of infection
Pathogen is engulfed by the phagocyte
Engulfed pathogen enters the cytoplasm in the phagocyte in a vehicle which is now called a phagosome
Lysosomes fuse with the phagosome releasing hydrolytic digestive enzymes which break down pathogen into waste material except the antigen
Waste material material are released from the cell by exocytosis
Antigen present is on the cell surface membrane and the phagocyte becomes an antigen-presenting cell
Response of t lymphocytes- cell mediated immunity which is a specific cellular response
T- helper cell with specific protein binds to APC which means it’s now activated as it differentiate by colonial selection by mitosis.
Differentiate into three types of cells
T - helper cell = specific T - helper cell vines to the antigen-presenting cell releases side cancer trap sites to area of infection releases cytokines that all activate TC cells and activate a specifically complimentary B cell form t- helper cells.
Tc cell = locate and destroy infected body cell binds to antigen-presenting cell which releases perforin which creates holes in the cell surface membrane destroying the APC
Activation of B - cells - humoral response
A specific TH cell where a receptor protein binds to the APC and locate an activates a specifically complimentary be cell which releases cytokines chemicals that signal specific B cell to occur by mitosis by clonal selection
B -cell then differentiate into two types of cells: plasma cells which secrete and produce vast quantities of specific antibodies into the blood plasma and memory B cells which remain in the body in response through pathogen rapidly and extensively for a secondary response.
Antibodies
protein made in response to a foreign cell has binding sides which bind specifically to an antigen. A specific antigen is produced by specific plasma cell cell.
Antibodies knowledge
Have a quaternary structure= made of four polypeptide chains which are two alpha chains and two beta chains. Too heavy chains and two short chains heavy and short depending on number of amino acids.
They have two binding sites
A variable constant, which is same in all antibodies
Variable region have a different primary structure and therefore a different tertiary structure therefore specific to each antigen
Form antigen antibody complexes
How do antibodies assist in the destruction of pathogens?
Agglutination = specific antibodies buying to the antigen on the pathogen and clump them together
Opsonisation = marking pathogen so phagocytes recognise and destroyed the pathogen more efficiently
Lysis = bind to antigen and lead destruction of pathogens membrane
Prevent pathogen replication
Memory cells
produced in response to a secondary response in the humoral response by colonial selection of activation of b cells
TH cells recognise antigen again and release cytokines. Memory cells are activated and divide rapidly by mitosis.
They can differentiate into plasma cells and even more memory cells
Plasma cell cells produce vast quantities of specific antibodies in a shorter period of time
Antigenic variability
this is one that is a mutation in the variable region of a anti body which means it’s no longer specifically complimentary to the antigen therefore no antigen antibody complexes formed therefore will not be able to initiate a secondary response as change in tertiary structure
Passive immunity=
No exposure to antigen
Antibodies are given
Short term
Fast acting
No memory cells produced
Active immunity
Exposure to antigen
Antibodies are produced
Long-term
Memory cells are produced
Takes a long time to develop
Vaccination
contain dead, weekend or attenuated version of pathogen
Vaccination ethics
Cost
Availability
Use of animals
Human testing
Heard immunity
if enough individuals in the population of vaccinated then there’s a little chance of the disease spreading therefore even non-vaccinated individuals will be protected
monoclonal antibodies
Antibodies produced from one clone of plasma b cells
Use of monoclonal antibodies
Research
Immuno assays
Diagnosis
Targeting drugs
ELISA test
Add patient blood sample to well bounded with monoclonal antigens
Specific antibodies in blood bind to antigen
Wash out excess
Add enzyme linked antibody which binds to a specific antibody
Wash out excess
Substrate is added and converted by enzyme into coloured product
Amount of coloured product shows the amount of time the patient has been infected
HIV structure
Lipid envelope
Capsid
Attachment proteins
RNA
Reverse transcriptase
HIV replication
Attachment proteins complementary and bind to proteins on T-helper cell
Capsule broken down and releases viral RNA
Reverse transcription convert viral RNA into C DNA
Viral C DNA incorporated into host DNA which is now infected
Transcription of viral DNA into mRNA
Translation of mRNA into HIV proteins
Formation of virions
Virions bud off host cell membrane forming their lipid bilayer
AIDS
fewer than 200 TH cells mm-3 of blood
More HIV
Destruction of more T-helper cell
Less activation of B-cell
Decrease production of antibodies so less able to destroy pathogen
How do antibiotics work?
Prevent bacteria from making a normal cell wall by targeting 70s ribosomes
This means that the bacteria are unable to resist osmotic pressure and the soul burst due to increase cell volume of water by osmosis
