With reference to monoclonal antibodies, often mentioned in news, consider the following statements:

[Nanotechnology]
I. They are man-made proteins.
II. They stimulate immunological function due to their ability to bind to specific antigens.
III. They are used in treating viral infections like that of Nipah virus.
Which of the statements given above are correct?

The correct option is I, II and III.

Let us analyze each statement step-by-step to understand why they are all correct:

Statement I: They are man-made proteins.
Monoclonal antibodies (mAbs) are laboratory-produced molecules engineered to serve as substitute antibodies. Since they are produced in a laboratory setup (often using hybridoma technology) to mimic the immune system's ability to fight off harmful pathogens, they are indeed man-made proteins. Therefore, Statement I is correct.

Statement II: They stimulate immunological function due to their ability to bind to specific antigens.
Antibodies are designed to bind specifically to one unique antigen (such as a specific protein on the surface of a virus, bacteria, or cancer cell). By binding to these target antigens, monoclonal antibodies can flag the target for destruction by other parts of the immune system, block binding sites, or trigger downstream immune responses. Thus, they stimulate immunological function due to their target-specific binding. Therefore, Statement II is correct.

Statement III: They are used in treating viral infections like that of Nipah virus.
Monoclonal antibodies have found widespread clinical applications in treating infectious diseases. For example, the monoclonal antibody m102.4 has been developed and used on a compassionate-use basis to treat infections caused by Henipaviruses, which include the deadly Nipah virus and Hendra virus. Therefore, Statement III is correct.

Since all three statements (I, II, and III) are correct, the correct option is I, II and III.