The development of a vaccine for AIDS might not be a reality in the near future. The AIDS virus is highly flexible and prone to mutations at a faster pace which preclude the possibility of developing a standard vaccine. This was stated by Prof. Rolf M Zinkernagel, winner of Nobel Prize for Medicine in 1996. He was awarded the Nobel Prize for his role in the discovery of how the immune system recognizes virus infected cells. He is presently working with the Institute of Immunology, University of Zurich, Switzerland.

Speaking to newsmen after his talk on the " Current Excitement in Biology" organised by the Centre for Cellular and Molecular Biology (CCMB), as part of its silver jubilee celebrations, Prof. Rolf said, "Some vaccines may come up which can prevent the spread of infection in the body at a slow pace and thus can prolong the life of the AIDS patients."

Elaborating the point Prof. Rolf said the virus mutates so fast that each of its versions would require a different kind of vaccine. "The moment you have a vaccine for one type of virus, it changes itself to overcome the vaccine and then a new vaccine has to be developed."

Prof Rolf said the slowdown would be enough to ensure the survival of the human species. Humans are capable of reproducing at the age of 15. Add another 15 years to ensure that his children can look after themselves and this would be enough to ensure the continuation of the species. However, he agreed that this scientific explanation was not a politically correct view.

In India, he said, the reach of the vaccination programme should be expanded considerably to control the spread of preventable diseases like TB, polio and measles. He said the advantages of the vaccination outdo its disadvantages. There should be more concerted efforts for the discovery of useful vaccines for dreaded diseases.

In his presentation at the technical session, Prof Rolf described how the recognition of the virally infected and tumour cells by the immune system occurs in the spleen and lymph nodes. When the response is against infection by a non-cytopathic virus or against a tumour cell, the response is primarily mediated by T cells and it reflects a finely-tuned balance between the immune cells or virally infected or tumour cells.