Multifactorial Immune Response Between Male and Female BALB/cJ and C57BL/6J Mice Exposed to Aspergillus fumigatus 2310270

Abstract Introduction Aspergillus fumigatus is an opportunistic airborne fungus that poses significant health risks, particularly to immunocompromised individuals and patients with preexisting conditions such as asthma. Despite its clinical relevance, the interplay between host sex, genetic background, and immune response to A. fumigatus exposure remains underexplored. This study investigated how immune cell counts, mucus production, collagen, and antibody production vary with sex and strain in BALB/cJ and C57BL/6J mice exposed to A. fumigatus. Methods Mice were challenged with airborne A. fumigatus spores weekly for three consecutive weeks. Bronchoalveolar lavage (BAL) was performed to collect immune cells, and histological analysis of lung tissue was conducted to assess mucus and collagen production, and an ELISA was conducted to analyze IgE antibody levels. Immune cells were identified using morphometric differences; mucus and collagen production were scored using Periodic Acid-Schiff (PAS) staining and Pico-Sirius Red (PSR) with Fast Green (FCF), respectively. Results Results showed that granulocyte counts peaked at day 3 post-challenge and declined by day 28, with male C57BL/6J mice exhibiting significantly higher granulocyte numbers than male BALB/cJ mice. While immune cell counts were not significantly different between sexes, mucus production varied. Male C57BL/6J mice had higher mucus production on day 3 post-challenge, whereas female BALB/cJ mice showed elevated mucus levels at day 28. Across all time-points and genetic background, females had significantly higher IgE production compared to their male counterpart. Conclusion This study highlights that genetic background (strain), timepoint and sex are important variables affecting , mucus, collagen, and antibody production dynamics in A. fumigatus mediated immune responses. These findings have implications for improving fungal disease models and developing sex-specific therapeutic strategies. Funding Source USR, Undergrad Students Research, SAFAC, CSHE and Judith Strong grant Topic Categories Immediate Hypersensitivity, Asthma, and Allergic Responses (HYP)