This year’s Nobel Prize in Physiology or Medicine goes to Harald zur Hausen of Germany for establishing that human papilloma viruses (HPV) cause cervical cancer. He gets half of the prize, and the other half is shared by two French scientists, Françoise Barré-Sinoussi and Luc Montagnier, for their discovery of human immunodeficiency virus (HIV).

The announcement that this year’s prize goes to three scientists, who discovered two viruses causing severe human diseases, was made to the press earlier today by the Nobel Assembly at the Karolinska Institutet in Sweden.

Harald zur Hausen

Harald zur Hausen was born in 1936 in Germany, and attained his MD at the University of Düsseldorf. He is Professor emeritus and former Chairman and Scientific Director of the German Cancer Research Centre in Heidelberg.

Zur Hausen’s discovery has led to the understanding of the natural history of HPV infection and how the virus leads to cancer, thus opening the door to developing vaccines that stop the virus taking hold.

Zur Hausen persisted against the majority view in the 1970s when he suggested HPV (human papilloma virus) caused cervical cancer, the most common cancer among women. He had a hunch that inside cervical cancer tumours were cancer cells whose DNA had been invaded by DNA from HPV and this could be found by looking for it in the cancer cell genome. While this sounds straightforward, it took ten years and was complicated by the fact that only parts of the viral DNA were fused in the host genome.

After painstaking work analysing biopsy after biopsy of cervical cancers, zur Hausen eventually found DNA from HPV type 16 inside tumour cells in 1983. Then in 1984 he cloned HPV 16 and 18 from patients with cervical cancer and showed that these two types were consistently present in about 70 per cent of cervical cancer biopsies from all over the world.

More than 5 per cent of all cancers worldwide are caused by persistent HPV infection. HPV is the most common sexually transmitted disease and affects between 50 and 80 per cent of the population. There are at least 100 types of HPV known to man, of which about 40 infect the genital tract, 15 of which are high risk factors for cervical cancer. HPV has also been linked to cancer of the penis, the vulva and the mouth and throat.

Nearly 100 per cent of the 500,000 women who are confirmed to have cervical cancer globally every year are infected with HPV.

Françoise Barré-Sinoussi and Luc Montagnier

Françoise Barré-Sinoussi was born in 1947 in France and got her PhD in virology at the Institut Pasteur in Garches, Paris. She is professor and Director of the Regulation of Retroviral Infections Unit in the Virology Department at the Institut Pasteur.

Luc Montagnier was born in 1932 in France and got his PhD in virology at the University of Paris. He is Professor emeritus and Director at the World Foundation for AIDS Research and Prevention in Paris.

Barré-Sinoussi and Montagnier found the human immunodeficiency virus (HIV), which is estimated to infect nearly 1 per cent of the human population. By discovering its shape, and how it behaved biochemically in the human immune system, they showed that this retrovirus (a retrovirus invades and fuses with DNA of host cells and replicates as part of that cell) was the first known human lentivirus, that is a virus with a long incubation period. HIV progressively weakens the immune system as lymphocytes invaded by the virus replicate and lose their power to protect the body against invading pathogens.

Barré-Sinoussi and Montagnier started their search in 1981 when reports of a new type of immunodeficiency syndrome began to emerge. They isolated cells from swollen lymph nodes of patients with early stages of the new acquired immune deficiency syndrome and cultured them in the lab. They detected sure signs of retrovirus activity when they found traces of reverse transcriptase, an enzyme that helps the RNA of the retrovirus to be copied into DNA format which then enables it to fuse with the DNA of the host cell. Another sure sign was the presence of retroviral “buds” on the infected cells.

By 1984, Barré-Sinoussi and Montagnier had isolated several samples of HIV from sexually infected individuals, haemophiliacs, mother to baby transmissions and blood transfusion patients.

Soon after this, other scientists proved HIV caused AIDS (acquired human immunodeficiency syndrome), and some went on to clone the HIV-1 genome which led to the discovery of important details about how the virus replicates and interacts with its host. It also helped to develop diagnostic and screening tools which in turn has helped to limit the pandemic and the development of new antiviral drugs.

Source: The Nobel Foundation.

Written by: Catharine Paddock, PhD.