Christened protein A, the wonder substance was extracted from the cell walls of the deadly staphylocossus aures bacteria by immunologists at the Bose Institute (BI) here.

``Strains of the staph bug, which causes food-poisoning, boils, abscess and wound infections, were found to ameliorate side effects of powerful drugs in mice by producing a lot of nitric acid inside their body cells,'' says the Director and Head of the Immunotechnology section of the Institute, Dr Prasanta Ray.

About two decades ago, ingredients in the bacterium were established to be considerably stimulating the immune system in animals. The recent research has revealed a tremendous power of protein A to bind tightly with Immunoglobin-G (IB-G), a class of antibodies circulating in the blood.

The BI immunologists teamof P K Ray, Tanya Das, V Subbulakshmi, Amiya Ghosh and Gaurishankar induced cancer in laboratory mice to test whether the malignant cells could be killed by gearing up the immune system with a follow up dose of protein A.

The cancerous tumours stopped growing after a small dose of the protein, twice a week for two weeks, Ray says.

The team then took up a study to explore the possible role of the protein against toxicity of the AIDS drug Azidodeoxythymidine (AZT), which, when used for a prolonged period, kills antibodies producing stem cells in bone marrow along with bringing down HIV levels in the blood stream.

A cocktail of protein A and AZT was seen to bring down HIV loads without harming these protective cells, Ray says.

The multi-potent biological response modifier will have significant use in treatment of cancer patients who have undergone chronic chemotherapy doses, as well as transplant and immuno deficiency disorder patients, he says.

The protein, which acts by metabolic biotransformation,detoxification, bioelimination and stimulation of growth factors, has also been found to have anti-fungal activity, along with anti-toxicity and immuno-modulator properties, he says.

The scientists will take up human trials later this year on cancer patients undergoing chronic chemotherapy.

The team published the results of their study in a recent edition of the biocehmical and biophysical research communication journal, and is coming up with another paper on amelioration of kala azar, causing Leishmania Donovani's toxicity in the journal immunology letters this month.