Molecules that generate an immune response when detected by the body. They are usually found on the surface of cells.
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What are pathogens?
Organisms that cause disease, e.g. bacteria, viruses and fungi.
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What are abnormal body cells?
Cancerous or pathogen infected cells that have abnormal antigens on their surface which trigger an immune response.
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What are toxins?
Poisons such as Clostridium botlinium.
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What is a phagocyte?
A type of white blood cell that carries out phagocytosis, found in blood tissues.
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What is the first step of phagocytosis?
Phagocyte recognises the foreign antigens on a pathogen.
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What is the second step of phagocytosis?
The cytoplasm of the phagocytes moves round the pathogen; engulfing it.
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What is the third step of phagocytosis?
The pathogen is now contained in a phagocytic vacuole in the cytoplasm of the phagocyte.
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What is the fourth step of phagocytosis?
A lysosome fuses with the phagocytic vacuole. Lysozymes break down the pathogen.
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What is the final step of phagocytosis?
The phagocyte then presents the pathogen's antigens - it sticks the antigens on its surface to activate other immune system cells. The phagocyte is acting as an antigen-presenting cell.
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What is a T Cell?
A T cell is another type of white blood cell with receptor proteins on its surface that bind to complementary antigens presented to it by phagocytes.
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What do helper T Cells do?
Release chemical signals that activate and stimulate phagocytes. They also activate B Cells which secrete antibodies.
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What do cytotoxic T Cells do?
Kill abnormal and foreign cells.
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What is a B Cell?
Another type of white blood cell covered in antibodies with proteins that bind to antigens to form an antigen-antibody complex.
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What are plasma cells?
They are identical to B Cells and secrete loads of antibodies specific to the antigen which are called monoclonal antibodies. They bind to the antigens on the surface of the pathogen to form lots of antigen-antibody complexes.
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How many binding sites does an antibody have?
Two; so it can bind to two pathogens at the same time. This means that the pathogens become clumped together which is called aggulation.
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What is a cellular response?
The T Cells and other immune system cells that they interact with, e.g. phagocytes.
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What is a humoral response?
B Cells, clonal selection and the production of monoclonal antibodies.
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What is a primary response?
When antigens enter the body for the first time it activates the immune system. It is slow as there aren't many B Cells.
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What is a secondary response?
If the same pathogen enters the body again, the immune system will produce a quicker, stronger immune response and clonal selection happens faster. Memory B Cells are activated.
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What is herd immunity?
When vaccines protect individuals that have them and because they reduce the occurence of the disease, those who are not vaccinated are less likely to get the disease.
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What is antigenic variation?
When some pathogens change their surface antigens so when you're infected a second time the memory cells produced cannot recognise the antigen.
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What is the ELISA test?
Allows you to see if a patient has any antibodies to a certain antigen.
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What is the direct ELISA test?
It uses a single antibody that is complementary to the antigen you're testing for.
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How do you carry out the direct ELISA test?
Patient sample bound to inside of a welll with antibody complementary to antgen also being added. If the antigen is present it will become imobilised and the antibody will bind to it. Washed out to remove any unbound antibody with substrate solution
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What is HIV?
Human immunodeficiency virus which infects and eventually kills helper T-Cells.
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What is AIDS?
Acquired immune deficiency syndrome which decreases immune system cells meaning the patient is susceptible to serious infections.
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Other cards in this set
Card 2
Front
Organisms that cause disease, e.g. bacteria, viruses and fungi.
Back
What are pathogens?
Card 3
Front
Cancerous or pathogen infected cells that have abnormal antigens on their surface which trigger an immune response.
Back
Card 4
Front
Poisons such as Clostridium botlinium.
Back
Card 5
Front
A type of white blood cell that carries out phagocytosis, found in blood tissues.
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