A researcher aims to produce a monoclonal antibody against a specific antigen (protein X) from a bacterial pathogen. She immunizes a mouse with protein X, then removes the spleen and fuses the B lymphocytes with myeloma cells to create hybridomas. After screening, she selects a hybridoma clone that secretes a single type of antibody, called antibody Y, against a specific epitope of protein X. Meanwhile, a patient infected with the same bacterium mounts a natural immune response, producing a mixture of polyclonal antibodies against multiple epitopes of the pathogen.
Compare the monoclonal antibody Y produced by the hybridoma method with the polyclonal antibodies produced during the natural immune response. In your answer, you should refer to:
- the molecular structure of the antibodies and how it relates to their function;
- the principles of using each type of antibody in diagnosis and treatment of disease;
- the differences between active and passive immunity relevant to the use of these antibodies.