Human Papillomavirus New cervical cancer vaccine developed

Cervical cancer: New vaccine concept against carcinogenic human papillomaviruses

Cervical cancer is the third most common cancer in women. However, the risk of contracting it can be significantly reduced: through the HPV vaccine. Researchers have now developed a new vaccine against carcinogenic human papillomaviruses.

Third most common cancer in women

Cervical cancer caused by certain human papillomavirus (HPV) is the third most common cancer in women worldwide. According to experts, more than 4,000 women a year contract this type of cancer in Germany - about 1,500 die of it. Well over 80 percent of cases are diagnosed in developing countries, especially in Africa and South America. However, the risk of developing this type of cancer can be significantly reduced by the HPV vaccine. Scientists at the German Cancer Research Center (DKFZ) have now developed a completely new vaccination concept. The vaccine is inexpensive and protects against almost all carcinogenic HPV types.

Although currently available, vaccines against human papilloma viruses (HPV) that are carcinogenic are temperature-sensitive and expensive. Researchers have now developed a new vaccine to improve HPV vaccination rates. (Image: adiruch na chiangmai / fotolia.com)

Transmission during sexual intercourse

Risk HPV are transmitted during intercourse, the infections are very common. It is believed that up to 80 percent of the female population in their lives are in contact with these viruses.

In addition to cervical cancer, infections with high-risk HPV are also associated with oral pharyngeal tumors.

A vaccine can provide protection.

Reduce the number of cervical cancer cases

In Germany, the Standing Vaccination Commission (STIKO) recommends the HPV vaccine for girls 9 years and older for years. This should significantly reduce the number of cervical cancer cases.

"There are currently several vaccines available in Germany that protect against infection with the most common carcinogenic HPV types," said Bavarian Health Minister Melanie Huml recently in a statement.

"My goal is that more girls than before decide for the vaccination - preferably even before the first great love. Because even at the "first time" girls can be infected with HPV, "said the Minister.

However, gynecologists advise even after the first sex for HPV vaccine. And even if an infection with HPV has already been through.

Temperature sensitive and expensive

Although the currently available vaccines against the carcinogenic HPV are effective, but associated with limitations, it says in a statement by the Wilhelm Sander Foundation, which was published by the "Information Service Science" (idw).

They are sensitive to temperature and therefore require continuously cooled transport, which is a logistical problem in some countries. Their production is also complex and expensive. In addition, they only work against some of the carcinogenic HPV types.

"Our big goal is to increase immunization rates against HPV worldwide, especially in countries that only have limited resources," says Martin Müller from the DKFZ.

"Our new, heat stable vaccine, which is cheap to produce and protects against almost all carcinogenic HPV types, is a first big step in that direction."

Stimulation of the immune system

Vaccines that protect against HPV infections stimulate the immune system to produce protective antibodies. The already available vaccines are based on so-called virus-like particles.

Researchers refer to empty protein envelopes that do not contain genetic material. They are produced in yeast or insect cells.

Vaccinated individuals then develop antibodies that prevent viruses from infecting the cells. As with influenza vaccines and almost all other prophylactic vaccines, HPV vaccines only protect when administered prior to infection.

The HPV vaccine newly developed in the working group of Martin Müller is based not on virus-like particles, but on small protein snippets of the virus envelope (HPV envelope proteins)..

The aim of this vaccination is to trigger the formation of protective antibodies. For this to be done efficiently, Müller and colleagues have the small fragments of HPV envelope proteins, the so-called L2 epitopes (molecular segments of viral antigens), of the eight HPV types 16, 18, 31, 33, 35, 6, 51 and 59 in the thermostable Scaffold protein (thioredoxin) of a heat-loving bacterium inserted.

The bacterial thioredoxin (Trx) thus carries all epitopes of the eight HPV antigens (cross-neutralization epitopes). Against each of these epitopes can now be formed by the immune system specific antibodies that bind to the surface of the virus, thus protecting the body from HPV infections.

Protection against almost all carcinogenic HPV

In addition, the working group has made further progress with a new procedure:

By adding the so-called OVX313 domain (protein domain: smallest, stably folded structure of amino acids within a protein that bind other molecules), seven Txr L2 proteins combine to form macromolecules (heptamers) of the vaccine protein. This significantly increases the effectiveness of the vaccine.

The production of the vaccine protein takes place in Escherichia coli (intestinal bacterium). While the thioredoxin is derived from a thermophilic bacterium (Pyrococcus furiosus) and is very heat stable, Escherichia coli has its temperature optimum at 37 ° C and is therefore not heat resistant.

"That's why we can very easily purify the vaccine protein at high temperatures; all other bacterial proteins are destroyed," Müller explained the advantages of the process.

In addition to this extraordinary stability, the vaccine has another advantage: it protects against almost all carcinogenic HPV and a number of so-called "low risk" HPV.

Improve HPV vaccination rates in poorer countries

With the help of the support of the project by the Wilhelm Sander Foundation, the vaccine could be improved and accurately characterized.

The preclinical results suggest that the vaccine can protect against almost 99 percent of all HPV-related cervical cancer cases.

In addition, protection against other HPV types is also conceivable that cause skin diseases and cancer of the pharynx and the anal area.

The new vaccine, with its many favorable properties, especially in poorer countries, should help to significantly improve the still insufficiently high HPV vaccination rates. (Ad)