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Normally in mammals, if tissue from another individual enters the body, the foreign cells are recognised as 'non-self' by the immune system - VCE - SSCE Biology - Question 5 - 2008 - Paper 1
Question 5
Normally in mammals, if tissue from another individual enters the body, the foreign cells are recognised as 'non-self' by the immune system. The tissue is then rejec... show full transcript
Worked Solution & Example Answer:Normally in mammals, if tissue from another individual enters the body, the foreign cells are recognised as 'non-self' by the immune system - VCE - SSCE Biology - Question 5 - 2008 - Paper 1
Step 1
Which cells of the immune system are initially responsible for recognising non-self cells introduced by an organ transplant?
Answer
The cells primarily responsible for recognizing non-self cells introduced by an organ transplant are T-helper cells. These cells play a crucial role in the immune response by assisting other immune cells in recognizing antigens that are foreign to the body, such as those found in transplanted tissues.
Step 2
How do the cells you have named in part i, distinguish between self and non-self cells?
Answer
T-helper cells, along with other antigen-presenting cells, distinguish between self and non-self cells by using their surface receptors. These receptors can detect specific self-markers and non-self antigens. When a T-helper cell encounters a non-self antigen presented on the surface of an antigen-presenting cell, it triggers an immune response against the foreign cells.
Step 3
Describe the process of tissue rejection after recognition of the non-self cells has occurred.
Answer
Once the immune system recognizes non-self cells in a transplanted organ, a series of events occur leading to tissue rejection. Initially, T-helper cells activate cytotoxic T cells and B cells. Cytotoxic T cells directly target and destroy the foreign cells, while B cells produce antibodies against the non-self antigens. This immune response results in inflammation and further recruitment of immune cells to the site, ultimately leading to the rejection of the transplanted tissue.