Shot in the dark
THE majority of malaria cases in India are caused by P vivax, a parasite that cannot be cultivated, making vaccine development difficult, according to Delhi-based Malaria Research Centre director V P Sharma.
Despite an annual expense of over Rs 200 crore on malaria control, Sharma fears that the malaria situation in India is going out of control. Not only are cases of malaria caused by P vivax spreading to new areas, but the incidence of cerebral malaria has also increased.
In that context, efforts being made by the Delhi-based International Centre For Genetic Research and Biotechnology's researcher Virander Chauhan to develop a vaccine against both P falciparum and P vivax become relevant. Claims Chauhan, "We are the first group to identify the antigens of an Indian malaria strain of P falciparum." The group is also working on P vivax.
Says Chauhan, "We propose to use a mixture of the 2 peptides as a cocktail vaccine in order to invoke responses against both the sporozoite and merozoite stages."
The first peptide is based on MSA-1 and RESA fragments whereas the second one is based on CSP. The group immunised mice with the mixture of the 2 peptides successfully and it is now being tested in rabbits and monkeys. Chauhan has also applied to the Indian Council of Medical Research (ICMR) to conduct preliminary trials of these possible vaccines on human volunteers.
In other laboratories, efforts are being made to understand the molecular biology of malaria parasites. Y D Sharma and his colleagues at the All India Institute of Medical Sciences, for instance, have unravelled the entire genome of P vivax and have identified 3 genes which code for 3 proteins, which could be used as vaccines in the future.