2.4 Immunity Flashcards
What are the non-self cells?
Cells from transplants, abnormal (cancer) cells, and cells infected by a virus.
What type of cell are cells from transplants, abnormal (cancer) cells, and cells infected by a virus?
Non-self cells.
Define an antigen.
Foreign protein, which stimulates an immune response.
Describe and explain the process of phagocytosis.
- Phagocyte attracted to pathogen as it recognises foreign antigen
- Phagocyte engulfs pathogen by endocytosis, and encloses it into a phagosome
- Phagosome fuses with lysosome
- Lysosome releases enzymes which hydrolyse pathogen
- Antigens displayed on cell-surface membrane
How is a phagocyte attracted to a pathogen?
It recognises foreign antigen.
In what process does a phagocyte engulf a pathogen?
Endocytosis.
What fuses with each other during phagocytosis?
Phagosome fuses with lysosome.
What type of response is phagocytosis?
Non-specific immune response.
What are the two types of phagocytes?
Neutrophils and monocytes, which mature to macrophages.
What is the longevity of neutrophils?
Short-lived.
What is the longevity of monocytes?
Mature to macrophages, which are longer-lived.
Describe the cellular immune response.
T cell receptor specific for single antigen, Th cell with complementary antigen binds to antigen presenting cell, causes activation of Th cells to rapidly divide by mitosis, producing clones.
What can clones of Th cells do?
Become T memory cells, stimulate the humoral response, stimulate cytotoxic T cells.
How do cytotoxic T cells result in the death of other cells?
Produce the protein perforin, which makes holes in the cell-surface membrane.
Describe the humoral immune response.
Antigen binds to surface receptor on B cell, B cell engulfs by endocytosis and presents antigens on surface, T helper cell with complementary receptor binds to antigens, stimulates B cell to rapidly divide by mitosis, activated B cell can differentiate into B memory cells or plasma cells.
What can activated B cells differentiate into?
B Memory Cells and Plasma Cells.
What is the longevity of B Memory cells?
Long-lived.
What is the longevity of plasma cells?
Short-lived.
What is the purpose of B Memory Cells?
Can rapidly divide into plasma cells if the same antigen is encountered.
What is the purpose of plasma cells?
Produce antibodies.
What are antibodies produced by?
Plasma cells.
When does agglutination occur?
When an antigen and antibody bind with each other, forming an antigen-antibody complex.
What is the result of an antigen and antibody binding with each other?
Agglutination.
What is the purpose of agglutination?
Attracts phagocytes to increase the rate of phagocytosis.