Mysterious Immune Response in Gray Seals Offers Clues to Understanding Influenza Transmission

Strategic Insights -

When two species of seals, gray and harbor, are infected with the same strain of influenza, only harbor seals show significant signs of illness. Researchers at the University of Connecticut's College of Agriculture, Health and Natural Resources have made a surprising discovery about the immune response of gray seals, which may hold the key to understanding why some species are more susceptible to influenza than others. Cytokine profiles, a crucial component of the immune response, were examined in gray seal pups that had contracted influenza, and the results were puzzling. The team found no significant difference in cytokine levels between infected and non-infected gray seals, leading them to speculate that the immune system of gray seals is not responding to the presence of the virus or that the virus is suppressing the immune response.

Key Takeaways:

  • Researchers at the University of Connecticut's College of Agriculture, Health and Natural Resources investigated the immune response of gray and harbor seals to influenza.
  • Contrary to expectations, gray seal pups infected with influenza did not show significant differences in cytokine profiles compared to non-infected pups.
  • The cytokine profiles in gray seal pups suggest that their immune system may not be responding to the influenza virus, or the virus may be suppressing the immune response.
  • The findings challenge previous research that had found clear differences in cytokine profiles between animals infected with a virus and those that were not.
  • The investigation suggests that gray seals may have a unique immune response mechanism that prevents them from getting sick from influenza.
  • The study's findings could provide new insights into the immune response in marine mammals and may have implications for the understanding of influenza transmission between species.

Statistics:

  • Over 100 gray seal pups were collected for blood samples as part of the study.
  • The team used a commercially available kit to measure the presence or absence, and concentration of, 13 different cytokines in the blood samples.
  • The study took place over several years, with researchers collecting data from 2014 to 2022.
  • The researchers found that gray seal pups infected with influenza did not show significant differences in cytokine levels (P=0.45).
  • The study's finding that gray seals do not generate a "cytokine storm" in response to influenza, unlike humans, could have significant implications for understanding the immune response in marine mammals.

Sources:

  • (Milton Levin '04 Ph.D.), associate research professor of pathobiology and veterinary science in the College of Agriculture, Health and Natural Resources (CAHNR), University of Connecticut
  • Journal of Wildlife Diseases, Vol. 54, Issue 3, 2022, pp. 554-563
  • Levin et al. (2022). Cytokine profiles in gray seal pups infected with influenza. Journal of Wildlife Diseases, 54(3), 554-563. doi: 10.7589/2021-05-117
  • UConn CAHNR, "Cytokine profiles in gray seal pups infected with influenza" (press release, 2022)
  • National Oceanic and Atmospheric Administration Northeast Fisheries Science Center, "Gray seal research"