Alan Ackermann, age 13, of Decatur, Ill., for his question:

WHAT IS INTERFERON?

Interferon is a protein molecule produced by the cells of man and other mammals. It prevents vital infections in new and uninfected cells by stopping the growth of viruses.

Alick Isaacs, a Scottish virologist, and Jean Lindenmann, a Swiss microbiologist, discovered interferon in 1957. It has not been widely used medically because there is no suitable source from which to produce it in large enough quantities.

Scientists at the present time are trying to develop ways that will stimulate body cells to produce interferon in the absence of a virus.

In the future, scientists hope that the main benefit of interferon will be to prevent, rather than cure, disease.