A recent study warned that human immune systems may fight against bacteria and space viruses from other planets in the future, as experts believe that microorganisms can be found in other worlds, and are looking for signs of them on Mars, Jupiter's moons, and Saturn.
According to the British Daily Mail, this life may not be as we know it, however, aliens can rely on different amino acids from life on Earth.
Experts from Exeter and Aberdeen tested how mammalian immune cells responded to rare-earth amino acids that are common in meteorites.
They found that immune cells could interact with unusual amino acids, but in a much less efficient way than their usual responses.
The results indicate that extraterrestrial microorganisms can pose a threat to future space missions, and to life on Earth if returned to our planet.
"The world is now well aware of the immune challenge posed by the emergence of completely new pathogens," said study researcher and microbiologist Neil Joe from the University of Exeter.
The microbiologist added, "We wondered what would happen if we were exposed to a microorganism that was recovered from another planet or moon where life has evolved," stressing that there are some unusual organic building blocks outside the planet that can be used to form cells of these strange microbes.
"Will our immune system be able to detect proteins made from these non-terrestrial building blocks if such organisms were discovered and returned to Earth and then accidentally leaked?" Neil Joe asked.
The research predicted that contact with extraterrestrial microorganisms may pose an immune threat to space missions that aim to restore living things from exoplanets and moons.