The researchers have found a protein called perforin that destroys harmful cells in humans, particularly those cells that cause cancer.

Melbourne and London team of scientists have found out that this protein creates hole in the cells and kill them.

James Whisstock of Monash University says that perforin is a cleansing and death weapon for human immune system. The protein brakes into cells that have been attacked by viruses or have become cancer cells. The immune system of our body cannot destroy the cancer cells.

The study will help in finding more effective way to fight fatal diseases like cancer, malaria, and diabetes.

The scientists also noted that perforin has the ability to turn the body against itself just like autoimmune disease conditions or tissue rejection after bone marrow transplantation.

Helen Saibil of Birkbeck College London said, "The first major step in understanding perforin came from the discovery that it is related to a family of bacterial toxins, including pneumolysin, which we had previously studied".

Since around 100 years, it is known that our immune system functions by creating a hole in a target cell, from where the toxic enzymes are pump and perforin protein is responsible for causing a hole.

The findings of the study have been published in the journal Nature.