Which of the following statements is not correct?

Options

A. Higher vertebrates can distinguish foreign organisms from self-cells.
B. Foetus receives antibodies from its mother through placenta, is an example of active immunity.
C. Cell-mediated immunity involves T- lymphocytes.
D. Antibodies against cancer-specific antigens are used for detection of certain cancers.

Answer

To determine which statement is not correct, let's analyze each option step by step:

### Step-by-Step Solution:

1. **Analyze Statement 1**: "Higher vertebrates can distinguish foreign organisms from self-cells."
- Higher vertebrates, including humans, have an immune system that can differentiate between their own cells (self) and foreign cells (non-self). This ability is crucial for mounting an immune response against pathogens.
- **Conclusion**: This statement is correct.

2. **Analyze Statement 2**: "Receives antibody from its mother through placenta is an example of active immunity."
- When a fetus receives antibodies (specifically IgG) from its mother through the placenta, it is acquiring pre-formed antibodies. This process is known as passive immunity because the fetus's immune system is not actively producing these antibodies; it is simply receiving them.
- **Conclusion**: This statement is incorrect. It describes passive immunity, not active immunity.

3. **Analyze Statement 3**: "Self-mediated immunity involves T-lymphocytes."
- Cell-mediated immunity is indeed primarily associated with T-lymphocytes (T-cells). These cells play a crucial role in the immune response, particularly in recognizing and destroying infected or cancerous cells.
- **Conclusion**: This statement is correct.

4. **Analyze Statement 4**: "Antibodies against cancer-specific antigens are used for the detection of certain cancers."
- Antibodies can be developed against specific antigens found on cancer cells. The presence of these antibodies can indicate the presence of cancer in the body. Techniques like ELISA are used to detect these antibodies.
- **Conclusion**: This statement is correct.

### Final Conclusion:
The statement that is not correct is **Statement 2**: "Receives antibody from its mother through placenta is an example of active immunity."

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