CHARACTERIZATION OF NEISSERIA TYPE IV PILUS DEPENDENT COLONIZATION BEHAVIOR IN MICE

Abstract

The Type IV pilus (Tfp) is a retractile filamentous structure produced by various bacteria shown to play a critical role in motility-associated behavior such as DNA uptake, protein secretion, host-cell interactions, and bacterial community development. During Neisseria-host interaction, Tfp activity affects bacterial infectivity and intracellular survival via the modulation of various host cell signaling pathways (Lee et al., 2003; Kallstrom et al., 1997; Lin et al., 1997; Ayala et al., 2001). The PilT motor protein is an essential component of Tfp responsible for pilus retraction and roce generation required for the elicitation of host cell responses. Previous research has demonstrated its role in Neisseria in vitro colonization; however, its effects in vivo remains unknown. Here, I use a natural mouse model that pairs ordinary laboratory mice with Neisseria musculi, the natural commensural of the wild mouse Mus musculi to study host and Neisseria factors affecting asymptomatic colonization (Rhodes et al., 2019). More specifically, this paper aims to characterize how pilT, which encodes the Tfp motor protein PilT, affects N. musculi colonization and persistence in A/J laboratory mice. Here we find that N. musculi colonization in the A/J oral cavity and gut exhibits cyclic behavior drastically more frequently than in CAST mice inoculated with the same isolates (Rhodes, K. unpublished data). This finding suggests that oral and gut colonization by N. musculi is not supported by A/J mice regardless of N. musculi genotype, which is fundamentally different from CAST mice, and points to the influence of host genetic factors or the microbiota on N. musculi colonization.