"Even though the human genome was first fully sequenced in 2003, there are still thousands of genes that we know very little about.
The 'C6' gene, which has existed in human body for more than 500 million years, holds the key to human immunity.
Australia's National Science Agency identified the new gene that plays a critical role in regulating the body's immune response to infection and disease.
The discovery could lead to the development of new treatments for influenza, arthritis and even cancer.
The gene, called C6orf106 or 'C6', controls the production of proteins involved in infectious diseases, cancer and diabetes.
"Our immune system produces proteins called cytokines that help fortify the immune system and work to prevent viruses and other pathogens from replicating and causing disease," said researcher Cameron Stewart.
"C6 regulates this process by switching off the production of certain cytokines to stop our immune response from spiraling out of control," she added.
The cytokines, regulated by C6, are implicated in a variety of diseases including cancer, diabetes and inflammatory disorders such as rheumatoid arthritis.
The discovery helps to improve the understanding of our immune system, and it is hoped that this understanding will enable scientists to develop new, more targeted therapies.
"Even though the human genome was first fully sequenced in 2003, there are still thousands of genes that we know very little about," said another researcher Rebecca Ambrose.
Having discovered the function of C6, the researchers are given the privilege of naming it.
The current name, C6orf106, reflects the gene's location within the human genome, rather than relating to any particular function.
The study appears in Journal of Biological Chemistry.