Thymic Eosinophils: What Are You Doing Here?

The thymus is a primary lymphoid organ where major types of T lymphocytes undergo essential developmental processes. Eosinophils are among the cell types present in microenvironments within the thymus, and perhaps surprisingly, the role of thymic eosinophils, especially during homeostatic conditions, remains unclear. Major physiological events impact thymic organization and function throughout life: including age-related involution, pregnancy, and exposure to chemotherapy or radiation.

Eosinophils respond to, but are not essential for control of an acute serovar Typhimurium infection in mice.

Eosinophils are a highly abundant cell type in the gastrointestinal tract during homeostatic conditions, where they have recently been reported to take on an activated phenotype following colonization by the bacterial microbiota. To date, there have been few studies investigating whether eosinophils respond to infection with enteric bacterial pathogens and/or investigating the requirements for eosinophils for effective bacterial pathogen control. In this study, we investigated the response of eosinophils to an acute enteric infection of mice with the bacterial pathogen serovar Typhimurium.

A Retrospective Analysis of Leadership, Awardees, and Member Gender Representation of the Canadian Society for Immunology.

The Canadian Society for Immunology (CSI) established a formal Equity, Diversity, and Inclusion (EDI) Committee with the goal of providing EDI advocacy and leadership within the CSI, as well as in the broader scientific community. A first task of this committee was to review the publicly available historical data on gender representation within the CSI's membership, leadership, award recipients, and conference chairs/presenters as a step in establishing a baseline reference point and monitoring the trajectory of future success in achieving true inclusion. We found that, except for overall membership and a specific subset of awards, all categories showed a historical bias toward men, particularly prior to 2010.

Chronic small intestinal helminth infection perturbs bile acid homeostasis and disrupts bile acid signaling in the murine small intestine.

Intestinal helminths have evolved an abundance of immunomodulatory mechanisms to ensure long-lived infections in mammalian hosts. To manipulate mammalian immune responses helminths can directly produce immunomodulatory molecules, but helminth infection can also elicit functional changes in the intestinal microbiome which can impact immune functioning. Here we examined how bile acids (BA)s, a group of host-produced, microbiota-modified immunomodulatory metabolites, were altered in abundance and composition during a murine small intestinal helminth infection.

Equity, Diversity and Inclusion in Canadian immunology: communication and complexity.

The Canadian Society for Immunology (CSI) organized an Equity, Diversity and Inclusion (EDI) training workshop during its 2022 Scientific Meeting to improve understanding of EDI and explore strategies to achieve EDI goals in the scientific environment. The workshop focused on identifying Specific, Measurable, Achievable, Realistic and Timely (SMART) goals related to EDI in academia through small group discussions and learning exercises. Attendees highlighted several equity considerations within the field of academic immunology, including financial barriers, lack of diversity in research teams and gender bias; they emphasized the importance of creating an inclusive and accessible research environment.

MHCII+CD80+ thymic eosinophils increase in abundance during neonatal development in mice and their accumulation is microbiota dependent.

Eosinophils are present in the thymus of mammals, yet their function at this site during homeostatic development is unknown. We used flow cytometry to determine the abundance and phenotype of eosinophils (here defined as SSchigh SiglecF+ CD11b+ CD45+ cells) in the thymus of mice during the neonatal period, the later postnatal period, and into adulthood. We show that both the total number of thymic eosinophils and their frequency among leukocytes increase over the first 2 wk of life and that their accumulation in the thymus is dependent on the presence of an intact bacterial microbiota.

Impaired host resistance to Salmonella during helminth co-infection is restored by anthelmintic treatment prior to bacterial challenge.

Intestinal helminth infection can impair host resistance to co-infection with enteric bacterial pathogens. However, it is not known whether helminth drug-clearance can restore host resistance to bacterial infection. Using a mouse helminth-Salmonella co-infection system, we show that anthelmintic treatment prior to Salmonella challenge is sufficient to restore host resistance to Salmonella.