Spontaneous preputial gland adenitis in Staphylococcus aureus-colonized male C57Bl/6 mice triggers a Th17-driven immune response
Colonization with the pathobiont Staphylococcus aureus increases the risk of endogenous S. aureus infections if the balance between host and microbe is disturbed. We developed a model of persistent S. aureus colonization using the mouse-adapted strain JSNZ. The bacteria transfer from parents to offspring, producing lifelong, usually asymptomatic colonization. Here we report that S. aureus-colonized adult male mice frequently develop spontaneous preputial gland infections (preputial gland adenitis, PGA), which are characterized by pronounced pus production and gland enlargement. This study aimed to characterize PGA in terms of phenotype, causative agents, and the pathogen-specific antibody and T cell responses. We compared three groups: naive mice, colonized PGA-negative mice, and colonized PGA-positive mice. PGA occurred in 8/12 (67%) of male breeding animals and in 17/25 (68%) of adult male offspring. The infection did not self-resolve and persisted for several months. Genotyping identified the colonizing strain JSNZ as the causative agent. The infection caused purulent inflammation, with massive bacterial aggregates and neutrophil infiltrates filling the gland lumen. This inflammation completely disrupted the glandular architecture. PGA induced a strong but localized release of IL-1, IL-1{beta}, IL-17, MIP-1, and KC in the infected gland. T cells from PGA-draining lymph nodes, as well as splenocytes, reacted to in vitro re-stimulation with a S. aureus antigen cocktail with the proliferation of Th17 cells, and the release of IL-17 and IFN-{gamma}, corresponding to a type 3/1- immune response. Colonized PGA-positive mice also mounted a robust S. aureus-specific serum antibody response. In conclusion, the pathology of this spontaneous, chronic S. aureus infection is driven by a strong, type 3-biased immune response that, however, fails to clear the bacteria. This endogenous PGA model provides a valuable tool for studying host-pathogen interactions in natural S. aureus infection.