Cell Recognition And Immine System Flashcards
What is an antigen
Is a protein and a molecule on the cell surface membrane of a foreign cell that triggers an immune response
Phagocytosis process
The phagocyte is attracted to the pathogen by chemical products of pathogen
Phagocyte has several receptors on cell-surface membrane to attach chemicals into surface
Lysosomes within the phagocyte migrate towards the phagosome formed when engulfing bacterium
Lysosomes released their lysozyme into phagosome where Hydrolyse the bacterium
The hydrolysis product of the bacterium are absorbed by the phagocyte
T lymphocytes response to a cell-meditated immunity
Distinguish invader cells from normal cells by:
Phagocytes that have been engulfed and hydrolysed a pathogen present some of a pathogens antigens on their own cell surface membrane
Body cells invaded by a virus present some of their viral antigens on their own cell surface membrane
Transplanted cells from individuals of the same species have different antigens on the cell Surface membrane
Cancer cells are different from normal body cells and present antigens on their cell surface membrane
Cytotoxic T cells
Kill abnormal cells and body fellas that are infected by pathogens, by producing a poet in called PERFORIN that makes holes in membrane. The holes in the membrane become freely permeable to all substances and all dies
B lymphocytes and humoral response
The surface antigens of an invading pathogen are taken up by B cells
The B cells presses the antigens and presents them on its surface
Helper T cells attach to the proceed antigens on the B cells thereby activating the B cells
The B cells is now activated to divide by mitosis to give a clone of plasma cells
The cloned plasma cells produce and secrets antibodies that exactly fits the antigen on the pathogens surface and then the antibody attaches to the antigens on the pathogens and destroys them
Or
Some B cells develop into Merlots cells which can respond to future infections but he same pathogen by dividing rapidly and developing into plasma cells that produce antibodies which is a SECONDARY RESPONSE
Antigen-antibody complexes
Variable ends house 2 antigens recognition sites which are complementary to a foreign antigen on the pathogen.
These are specific to one type of antigen and bind forming an antigen-antibody complex
This leads to the destruction of the antigen, limited to agglutination and phagocytosis of bacterial cells
What is meant by heard immunity
To vaccinate the vast majority of the vulnerable population
Replication of T helper cell
Once in the body the protein in the HIV virus racist bonds to a protein cakes CD4. While this protein occurs in a number of different cells, HIV mostly attaches to T helper cell
The protein capsid fuses with the cell surface membrane. The RNA and enzyme of HIV enter the T helper cell
The HIV reverse transcriptase converts the viruses RNA to DNA
The newly made DNA is moved into the T helper cells nucleus where it’s inserted into the cells DNA
The HIV DNA in the nucleus created mRNA using the cells enzymes. This mRNA contains instructions for making new viral proteins and the RNA to go to the new HIV
The mRNA passes out of the nucleus through the nuclear pore and uses the cells protein synthesis mechanisms to make new HIV particles
The HIV particle break away form the T helper cell with a piece of its cell surface membrane surround them which forms the lipid envelope
What is antibiotics ineffective against viruses
As some antibiotics in hits enzymes involved in the formation of ‘normal’ muerin cell walls - weakens the cell walls
Monoclonal antibodies
Targeting medication to specific cell type by attaching a therapeutic drug to an antibody
Specific to antigens of cancer cells
Once attached to cancer cells and block the chemical signals stimulated their uncontrollable growth
Or another one would be attaching a radioactive or cytotoxic drug to the monoclonal antibody
Monoclonal antibodies
Medical diagnosis
Diagnosis of influenza, hepatitis and chlamydia were they produce a more rapid result than conventional method of diagnosis
Monoclonal antibodies
Ethical reasons
As people don’t believe it is right to kill move by injecting them with cancer cells
Defence mechanisms
Non specific and specific
