Assessing Age-Related Decline in Anti-Bacterial Immune Responses Using an Ex-vivo Assay in African Turquoise Killifish ( <i>Nothobranchius furzeri</i> )

Abstract Ex-vivo immune functional assays serve as essential tools for uncovering the intricate molecular mechanisms behind immune responses, both intrinsic and extrinsic, across a diverse spectrum of conditions and interventions. In this study, we devised an innovative assay aimed at quantifying anti-bacterial responses in immune cells from the primary immune organ of small teleosts. Our model of choice is the the African turquoise killifish ( Nothobranchius furzeri ), which has emerged as a prominent model system in the field of biology of aging, because of its natural short lifespan and the broad range of aging-related dysfunctions. Using our novel ex vivo assay, we tested age-associated differences in immune cell functionality, measured as anti-bacterial responses in young and aged turquoise killifish. Our results show that the ability to inhibit bacterial growth declines in cells extracted from aged killifish, compared to young killifish. This ex-vivo assay, designed for rapid measures of immune effector responses, holds the potential to be a scalable tool for assessing the cellular and molecular basis for anti-microbial immune responses under a range of interventions.