Updated 26 August 2020

Germs from space could cause havoc in human bodies

How would our immune systems react to microorganisms from other planets?

  • The more humans explore space, the more likely they will come into contact with alien microorganisms
  • A study sought to find out how mammalian immune systems might react to synthesised amino acids found on meteorites
  • This highlights the importance of containment protocols for future space missions, and protecting astronauts' health

As humans are gazing towards the stars and more specimens are brought back from space to study, there might be some unwelcome stowaways that bring new diseases to our fragile planet.

Or worse, it might jeopardise the health of astronauts exploring the farther reaches of our universe, whose immune systems are already taking a beating from space travel. 

READ | Nasa’s new space toilet makes it easier for women astronauts to go to the bathroom 

Germs are quite resilient creatures and have been found on certain types of meteorites and bodies of water found off-planet, and their genetic makeup is quite unknown in our planet's ecosystems.

Synthetic space germs

Scientists created synthetic amino acids similar to those found on these meteorites – but not commonly found on Earth – and studied whether a mammal-type immune system would be able to recognise and respond to these alien invaders. 

They replicated isovaline and α-aminoisobutyric acid into peptides – two strands that are not common on Earth, but have been found on meteorites and could be a basis for life outside our planet.

"If microbial life evolved outside Earth, it is conceivable that the composition of such organisms may include such unusual, but available, organic molecules."

Their findings – published in Microorganisms – indicate that while our T-cells do activate an immune response to these extraterrestrial-like antigens, the system was more ineffective than usual with reduced T-cell activation and proliferation.

READ MORE | Clots in space: How an astronaut's blocked vein brought medical insight

Astronauts' compromised health

An astronaut's immune system is especially compromised during and after space travel, where studies have proven decreased T-cell effectiveness, even without the introduction of foreign microorganisms. 

This could put the biosecurity of humans and life on Earth at serious risk, especially as more planets with water bodies are discovered and become potential destinations for space missions.

"We, therefore, speculate that the encounter of putative exo-microorganisms of an unusual antigenic repertoire might pose an immunological risk for space missions aiming to retrieve potentially biotic samples from exoplanets and moons."

Importance of containment

This is especially important when it comes to samples taken from alien bodies of water. 

"On Earth, the boundary conditions under which life can exist have shown that microbial life is possible even at extremes of temperature, pH, pressure, radiation, salinity, energy, and nutrient limitation, as long as there is liquid water."

And who knows what kind of dangerous microbes these liquid havens could be harbouring, which creates the need for strict containment protocols when the likes of SpaceX or Nasa start collecting these types of extraterrestrial samples. 

However, that is not to say that these germs would actually have any effect on the human body, and might not even be able to adapt to their host's biology. They could, however, be toxic in some form or trigger an allergic reaction.

The next step for this first-of-a-kind research would be to test the immune system's response to other microorganisms, sugars and proteins that hail from the stars. 

READ | Learning to live on Mars

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