Monoclonal antibodies (mAbs) are highly specific proteins with diverse applications in clinical diagnostics and medicine.
Legionella pneumophila is a waterborne bacterium that causes Legionnaires' disease, a severe form of pneumonia that can be fatal if untreated. Medical researchers have developed humanised monoclonal antibodies targeting specific surface antigens and toxins of L. pneumophila.
Legionella pneumophila can be diagnosed from a patient's bronchoalveolar lavage (BAL) fluid. A smear of the BAL fluid is fixed onto a microscope slide. Describe how humanised mAbs conjugated to a fluorescent marker can be used to confirm the presence of L. pneumophila on this slide.
In pre-clinical trials, these mAbs were shown to neutralise a cytotoxic pore-forming protein secreted by L. pneumophila that damages lung epithelial cells. Explain how neutralisation of this toxin by mAbs helps the patient recover from the infection.
The anti-toxin mAb therapy is safe and effective in animal models. It is now ready to progress to clinical trials on humans. Describe how these clinical trials should be designed and conducted to test this new therapy before it can be approved for general medical use.
Early monoclonal antibodies were produced entirely from mouse plasma cells. Explain why using transgenic mice that produce humanised antibodies is more successful for treating patients than using original mouse-derived antibodies.