Sixteen rodent passengers are to accompany astronauts on Discovery's last flight to aid a better understanding of human fitness.
The project is aimed at understanding why space flights make humans more vulnerable to infection by viruses and bacteria.
"Since the Apollo missions, we have had evidence that astronauts have increased susceptibility to infections during flight and immediately post-flight - they seem more vulnerable to cold and flu viruses and urinary tract infections, and viruses like Epstein-Barr, which infect most people and then remain dormant, can reactivate under the stress of spaceflight," said Dr. Roberto Garofalo, a professor at UTMB Health and principal investigator for the project.
"We want to discover what triggers this increased susceptibility to infection, with the goal both of protecting the astronauts themselves and people with more vulnerable immune systems here on Earth, such as the elderly and young children," he added.
Within two hours of the shuttle's return to Earth, eight of the animals will be infected with a virus called respiratory syncytial virus- a pathogen that causes a relatively harmless cold-like upper respiratory disease.
Garofalo's team will conduct genetic and protein studies of the lung and nasal tissues of both sets of mice, evaluating lung inflammation, viral replication and other key factors related to RSV infection in mice.
"We have substantial experience using mice to study immune response to RSV infection, and that will enable us to look at all the aspects of the immune responses of these mice as well as the pathological manifestations of the disease, looking at ways in which the space environment affects this respiratory infection," Garofalo said.
The project is important as NASA plans human expeditions beyond the relative safety of Earth orbit - to Mars, for example, or the asteroids.
"The space station provides a unique environment for generating answers to fundamental questions about the human immune system. Those answers will benefit people here on Earth, and there's been a lot of interest in pursuing them."