Honors Biology Blog
Immune System Quiz
When a virus is detected in the human body, it is first detected by tissue microphages and dendritic cells that constantly keep surveillance for invading pathogens. When the pathogen is detected, the microphage attempts to eliminate the pathogen and recruits other innate inflammatory cells. Neutrophils are then attached to the site of infection by chemokines. These neutrophils then begin to engulf and destroy the invading pathogen. Neutrophils do not live long lives and when they die they become pus, which is associated with infections.
If this attack on the virus fails, then the mighty T and B cells are activated to fight the infection. The resting T and B cells in the lymph nodes are stimulated by antigen. These resting cells then proliferate into both effector and memory T cells and B cells. Effector cells immediately attack the infection while Memory cells analyze and develop an immune memory to fight off future infections.
In order to fight off future infections two different processes are used.
Proliferation - a clone of the original cell with TCR or BCR is produced with the same antigen specificity as the original infection.
Differentiation - the infection is memorized as either an effector or memory T or B cell.
By analyzing the infection when it initially attacks the human body, proliferation and differentiation are used to ensure that the virus cannot do the same damage that it did to the body the first time around.
Recognition of invading cells from outside the body is initiated when a certain pattern recognition receptors are triggered by microbe-specific motifs known as pathogen-associated patterns. These patterns are essentially warning signs for microbe-invaders. These pathogen-associated patterns allow the cells to distinguish between invading cells and inmate cells.
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This information about the immune system connects to the process by which the immune system fights cancer in the human body. When the cancer is benign, it is more likely to be able to be engulfed and destroyed by the neutrophils and T and B cells; however, when the cancer becomes malignant it spreads throughout the body and this immune system process becomes less effective. Also, the cancer is constantly multiplying, so if the immune system cannot fight the cancer quickly enough, then the cancer will continue to spread and multiply. I can now connect this to chemotherapy where all cells, regardless of whether or not they are cancer, are destroyed in the hopes that the cancer will be killed and the inmate cells can eventually rebuild and fix the damage that was caused by the chemotherapy. By understanding the immune system, I can now understand why treatments like chemotherapy are used to fight cancer.
