05/16/2025
By Irma Silva

The Kennedy College of Sciences, Department of Biological Sciences, invites you to attend a master’s thesis defense by Alexander Gouvin-Moffat entitled "Variation in splenic adaptive immunity of wild threespine stickleback fish is associated with individual and population-level extrinsic variables."

Candidate: Alexander Gouvin-Moffat
Date: Thursday, May 29
Time: 2-4:30 p.m.
Location: Southwick 240

Committee members:

  • Natalie Steinel, Associate Professor, Department of Biological Sciences, Kennedy College of Sciences
  • Frédéric Chain, Associate Professor, Department of Biological Sciences, Kennedy College of Sciences
  • Rick Hochberg, Professor, Department of Biological Sciences, Kennedy College of Sciences

Abstract:
Immunological variation is a key determinant in infection outcome, but specific causes of immune variation are difficult to attribute in natural settings due to complex host-pathogen-environment interactions. Threespine stickleback fish are a developing model for examining immune heterogeneity, as wild populations can show distinct and sometimes heritable innate immune profiles and anti-parasite responses, such as peritoneal fibrosis (pathological constriction of internal organs caused by collagen deposition). We have previously confirmed the potential for stickleback parasites to modulate their hosts’ splenic adaptive immune phenotype (B and T cells) by showing reduction of these cells in lab-reared stickleback infected with the S. solidus tapeworm. However, cell-level splenic adaptive immunity of wild stickleback fish has not been examined. To test this, we characterized cellular adaptive immune phenotypes of 8 matched wild and lab-reared populations using RNA-ISH. Lake had the strongest effect on both B and T-helper cell RNA quantity of wild fish, and T-helper cells were elevated in S. solidus-infected fish but only if mild fibrosis was also present. Conversely, lymphocyte profiles at the individual level did not differ between lab populations, likely due to phenotypic plasticity from being in a uniform, pathogen-free environment. Average immune variables of each lab population were also significantly correlated with size and transparency of ancestral lakes, suggesting these may be particularly important drivers of local adaptation in splenic adaptive immunity. Future research will examine changes in splenic adaptive immune phenotypes of these wild populations over time and integrate findings with our collaborators who study their ongoing changes in genetics, microbiome, diet, and morphology.