Indian researchers claim that they have got some positive early leads for developing a vaccine that will prevent people contracting human immunodeficiency virus (HIV).

Blood samples of 128 HIV-infected individuals collected for a preliminary screening showed four “neutralising antibodies” that can block HIV. Studies are on to ascertain whether any one of these or a combination of these can be used as a vaccine to protect against the Indian HIV subtype, Clade-C.

“These are good signals, but we are not sure. More research needs to be done,” said Bimal Chakraborty, head of the research group at the International AIDS Vaccine Initiative (IAVI) laboratory at the Translational Health Science and Technology Institute (THSTI). These individuals were rare and samples needed to be screened further for sensitivity to a panel of viruses.

“At least two laboratories have identified the outer protein of the virus and made its crystal structure,” said Wayne C. Koff, IAVI chief scientific officer. “We will examine if the Indian proteins are acting against these four vulnerable sites on the outer shell of the virus.”

The developments have taken place in the past three months, raising hopes of developing at least a therapeutic, if not preventive, vaccine. A world without AIDS now looks a possibility, researchers believe.

The isolation of the antibodies led to establishment of a global project ‘Protocol G,’ and in India it was taken up by the THSTI. Researchers received 200 blood samples from the Chennai-based non-governmental organisation, YRG Care, which was founded by Dr. Suniti Solomon, who first detected HIV in India in the 1980s.

Vaccines prevent nearly three million deaths every year from infectious diseases, avert disease morbidity and enable more rapid economic and social development. Tuberculosis, HIV and malaria are the major diseases for which preventive vaccines are not available.

Despite global efforts, the scientific community is nowhere close to developing a vaccine to prevent HIV infection because HIV isolates are highly variable. There is lack of an ideal animal model for HIV to screen vaccines. HIV infects, suppresses and destroys key cells of the immune system. Importantly, natural immunity to HIV fails to completely control infection.