Immunology

Step 1: Understanding terms.
- Paratope: Antigen-binding site of the antibody.
- Epitope: Antigenic determinant present on the antigen.
- Agretope: Part of antigen that binds to MHC molecules.
- Idiotope: Each unique antigenic determinant in the variable region of the antibody itself. Step 2: Conclusion.
Thus, the correct term for antigenic determinants of the antibody variable region is idiotope.
Final Answer:

Step 1: Understanding primary vs. secondary immune response.
- Primary response: slower, longer lag phase, lower affinity antibodies (mainly IgM).
- Secondary response: rapid, short or no lag phase, high affinity antibodies (mainly IgG).
Step 2: Eliminating incorrect options.
- IgG is characteristic of secondary response.
- High affinity antibodies are produced in secondary response.
- Short/no lag phase is also typical of secondary response.
Thus, “Low affinity antibodies” is not a characteristic.
Final Answer: