Pathogen-produced catalase affects immune priming: A potential pathogen strategy

• Published in: Microbial pathogenesis Vol. 125; pp. 93 - 95
• Main Authors: Medina-Gómez, Héctor, Farriols, Mónica, Santos, Fernando, González-Hernández, Angélica, Torres-Guzmán, Juan Carlos, Lanz, Humberto, Contreras-Garduño, Jorge
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.12.2018
• Subjects: Animals; Antioxidants - metabolism; Catalase - metabolism; Entomopathogens; Immune Evasion; Immune memory; Immunologic Factors - metabolism; Innate memory; Metarhizium - enzymology; Metarhizium - immunology; Metarhizium anisopliae; Pathogen virulence; Survival Analysis; Tenebrio - immunology; Innate memory; Metarhizium anisopliae; Pathogen virulence; Immune memory; Entomopathogens
• ISSN: 0882-4010; 1096-1208
• DOI: 10.1016/j.micpath.2018.09.012

Immune priming in invertebrates occurs when the first contact with a pathogen/parasite enhances resistance after a second encounter with the same strain or species. Although the mechanisms are not well understood, there is evidence that priming the immune response of some hosts leads to greater pro-oxidant production. Parasites, in turn, might counteract the host attack with antioxidants. Virulent pathogen strains may therefore mask invertebrate immune priming. For example, different parasite species overexpress catalase as a virulence factor to resist host pro-oxidants, possibly impairing the immune priming response. The aim of this study was firstly to evaluate the specificity of immune priming in Tenebrio molitor when facing homologous and heterologous challenges. Secondly, homologous challenges were carried out with two Metarhizium anisopliae strains (Ma10 and CAT). The more virulent strain (CAT) overexpresses catalase, an antioxidant that perhaps impairs a host immune response mediated by reactive oxygen species (ROS). Indeed, T. molitor larvae exhibited better immune priming (survival) in response to the Ma10 than CAT homologous challenge. Moreover, the administration of paraquat, an ROS-promoting agent, favoured survival of the host upon exposure to each fungal strain. We propose that some pathogens likely overcome pro-oxidant-mediated immune priming defences by producing antioxidants such as catalase. •The role of pathogens on the immune priming outcome has been poorly investigated.•We propose that pro-oxidants might be very important to kill the enemies during immune priming.•We found that fungus that overexpress catalase impaired the immune priming.•Host or parasites might determine the immune priming outcome by exploiting the balance between pro-oxidants-antioxidants.