Investigation of the antifungal activity of Galleria mellonella hemolymph immunized with Candida albicans

• Grant number: 25/10369-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: July 01, 2025
• End date: June 30, 2026
• Field of knowledge: Biological Sciences - Microbiology - Applied Microbiology
• Principal Investigator: Maíra Terra Garcia
• Grantee: Gustavo Calixto Fernandes
• Host Institution: Instituto de Ciência e Tecnologia (ICT). Universidade Estadual Paulista (UNESP). Campus de São José dos Campos. São José dos Campos , SP, Brazil

Abstract

Over the past 10 years, interest in studies using Galleria mellonella has increasedsignificantly. This is due to several advantages that this alternative infectionmodel offers, such as ease of rearing, alignment with the 3Rs principles, andsuitability for large-scale use. The similarity of the innate immune response ofthese larvae to that of humans is also a major highlight. This immune system iscomposed of cellular and humoral responses that work together to protect theorganism and are being extensively studied. Although G. mellonella larvae do notpossess an adaptive immune response, they exhibit a certain degree of plasticity,which helps them adapt to external stimuli, such as infections caused by Candidaalbicans. Recently, the World Health Organization (WHO) classified C. albicansas a critically prioritized pathogenic fungus, alongside Cryptococcus neoformans,Aspergillus fumigatus, and Candida auris. This classification is due to its highprevalence in immunocompromised patients and its strong resistance toconventional treatments. Therefore, there is an urgent need to develop studiesaimed at discovering new alternative treatments for these infections. In thiscontext, the objective of this research project is to investigate the antifungaleffects of the hemolymph of Galleria mellonella after immunization with C.albicans. Initially, a screening will be conducted to identify the best reagentcapable of inhibiting melanization after hemolymph extraction-this step is crucialto prevent melanization from interfering with subsequent tests. Next, a test will beconducted to determine the sublethal dose capable of stimulating the larvalimmune system. For this, different concentrations of C. albicans (10¿, 10¿, and10¿ cells/mL) will be used for larval immunization. After 1, 2, 4, and 8 hours, thehemolymph from these larvae will be collected and centrifuged. Once free ofhemocytes, the hemolymph suspension will be immediately used to assessantifungal activity against C. albicans through killing curve and biofilm formationassays. The results will then be analyzed using GraphPad Prism 10 software witha significance level of 5%.