Why Humans get Sick from Viruses and Primates Don't

Kathleen Blanchard's picture
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If you’ve ever wondered why humans get sick from viruses like HIV, but animals don’t, new research provides some insight.

Scientists have found that even though humans and their close primate relatives share the same genes, there are functional differences in immune signaling pathways among species that explain human susceptibility to viruses, infection and even cancer that are not shared.

Compared to humans who suffer worse effects from HIV, malaria, hepatitis B, and cancer, primates have an innate evolutionary ability to fight infection, despite similar gene expression patterns.

The new research found unique HIV-interacting genes in chimpanzees, explaining why they don’t develop AIDS after HIV/SIV infection, but humans do.

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Even though humans and primates share the same evolution and genes, the researchers who tested functional differences in primate immune pathways, found variations that explain why humans and primates differ in the way they fight viruses and infection and also explain why humans are more susceptible to diseases that the animals are immune to.

The study authors write, "Our results indicate that “core” immune responses, those that are critical to fight any invading pathogen, are the most conserved across primates and that much of the divergence in immune responses is observed in genes that are involved in response to specific microbial and viral agents."

The research showed specific expression of genes explaining the difference between human and primate susceptibility to infection that they say will require more study.

The scientists plan to test the immune response of primates to specific infections to find more unique immune responses of the primates uncovered in the current study. Until now, scientists weren’t sure why immune systems of primates are different from humans.

PLOS Genetics

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