One wears a prim white bonnet. Another sticks out its tongue, hands resting over abdomen. A third clutches at its chest, mouth seemingly frozen in a scream. They are faces from the past, trapped in the appearance they bore when laid to rest nearly 300 years ago.

And disturbed from their eternal sleep, these mummies may help unlock the secrets of the immune system.

Resting in cardboard boxes in long rows of cabinets on the top floor of the Hungarian Natural History Museum in Budapest, the 265 mummies are helping scientists find new ways to treat tuberculosis.

Buried between 1731 and 1838 in the crypt of a Dominican church in the northern Hungarian town of Vac, the naturally-preserved mummies were forgotten for decades and discovered in 1994 during the church's renovation. They had lain in gracefully-painted pinewood coffins, some decorated with pictures of skulls.

The mummification process happened thanks to the favorable microclimate inside the crypt, including low temperatures and relatively constant humidity and air pressure. Wood chips placed under the bodies in the coffins absorbed fluids, so instead of decomposing, the bodies gradually dried out - preserving them in an astonishingly lifelike state.

Reflecting a wide sample of Vac residents, the mummies include three nuns, 30 priests, the wife and child of the local postmaster, surgeons, the founder of the Vac hospital and first director of the town's school for the deaf. "What was probably the most exciting and most comprehensive study was the one about tuberculosis," said Ildiko Pap, head of the Department of Anthropology of the Hungarian Natural History Museum. "In some of the individuals, the traces of the mutations on the bones caused by tuberculosis are evident to the naked eye."

According to the World Health Organization, nearly 1.5 million people died of tuberculosis in 2010, when 8.8 million new cases were reported. Around one-third of the world's population, over 2 billion people, has latent tuberculosis, which means they have been infected by the bacteria but do not show symptoms of the illness and cannot transmit the disease.

Pap said that all but 99 of the mummies have been identified and a large trove of information has been gathered about most of them, thanks to birth and death registers in the church, the names and dates on the coffins and other research done since their discovery.

The tuberculosis studies are being carried out in collaboration with experts from University College London and The Hebrew University of Jerusalem.

Eighty-nine percent of the mummies, ranging in age from newborns to over 65, had at one point been infected with tuberculosis and around 35 percent were suffering from the disease at the time of death. The strains of tuberculosis found in the people buried in Vac offer a unique chance to study the pathogens from a time before the development of antibiotics and prior to the spread of the Industrial Revolution.

The discovery of penicillin and subsequent development of other antibiotics in the 20th century virtually wiped out diseases such as tuberculosis that were once major killers in developed countries.

But the overuse and misuse of drugs have allowed old bugs to fight back and eventually overpower antibiotics, rendering some useless.

"We can say that 89 percent of these people were infected by tuberculosis or its pathogen during their lifetime," Pap said. "Their immune system was likely better than ours. If we could locate some gene sections and discover why they were more resistant to tuberculosis than us, then that could be of great assistance to modern medical science."

She said that the study of the mummies could lead to the development of new tuberculosis medication or the discovery of genetic changes that have affected our reaction to the disease.

Dr. Ruth McNerney, senior lecturer in Pathogen Biology and Diagnostics at the London School of Hygiene and Tropical Medicine, said that the research on the Hungarian mummies could provide a historical reference for the development of the disease.

"These samples were taken from before drugs were around ... so they represent early TB," said McNerney, who is not connected to the mummy research. "If we can pin down areas in the DNA of these mummies and see how they differ from modern (DNA), it might help us understand why modern TB drug resistance is developing."

Forensic expert Agnes Kustar has been working on the facial reconstruction of one of the most striking mummies in the lot - Baroness Antonia Tauber.

She was a nun descended from a prominent family, had a pronounced humpback and suffered from tuberculosis. Contemporary records describe the baroness as an excellent teacher - `zealous and loveable, a kind soul.'

To carry out facial reconstruction, experts need a detailed CT scan of the mummy, which gives a 3D picture of the skull. It can then be transformed into a plastic model identical to the original face.

This mummy has a special place in the hearts of the team.

"She has become a familiar person to us," said Kustar. "We were able to get to know her face and through it her whole personality."