C.1. Experimental rigor: We will apply our established in vitro and in vivo analyses to the studies proposed in both aims (31, 41, 42). Our preliminary data demonstrated the vigorous infection in both Heterozygotes (Foxn1nu/+) and homozygotes (Foxn1nu/nu) NU/J mice at mucosal sites. To minimize the possible variations in the animals, we will use siblings of these two inbred mouse strains. For the experiments proposed in both specific aims, we will use fifteen animals in each group to capture changes at three disease stages: 1) early (day 5 post infection), 2) intermediate (week 10 post infection), and 3) late (week 40 post infection) to generate statistically sound data. All the experiments proposed will be carried out at least …show more content…
Neutrophils and NK cells are associated with the decreased local MmuPV1 infection in immunocompetent mice. Previous studies demonstrated that adaptive immunity is sufficient to eliminate skin MmuPV1 infection in immunocompetent mice (44, 45). We tested heterozygous NU/J mice (Foxn1nu/+) at both cutaneous and mucosal sites together with homozygous (Foxn1nu/nu) NU/J mice. All Foxn1nu/+ NU/J mice had persistent mucosal infections (Fig. 3A). The viral copy numbers (vaginal, anal and oral lavages) were significantly lower than those of the homozygous siblings at all the time points post infection (Fig.3B). More Neutrophils cells were detected in infected tissues in the vaginal tract of the heterozygotes when compared with those of the homozygotes (Fig. 3C and D). More NK cells were also detected at the tail tissues of the heterozygous NU/J mice (data not shown). Tissue resident NK cells are very different from conventional splenic NK cells by producing cytokines, particularly TNFα and GM-CSF, instead of IFNγ (52, 53). This difference in resident NK cells may contribute to the tissue-specific disease outcome. These findings suggest that neutrophils and NK cells may have contributed to lower MmuPV1 infection in immunocompetent heterozygous NU/J …show more content…
Delayed viral clearance at the mucosal infected sites of the Ifnar−/− mice. We tested whether type I interferon pathways play a role in the MmuPV1 infection using Ifnar-/- mice. No cutaneous diseases were found in these animals (data not shown). The virus persisted at mucosal sites up to week 12 (Fig. 4A, B) while the viral DNA usually became undetected by week 4 post infection in the wild type animals (data not shown). These findings suggest that interferon pathways play a role in the viral clearance in our mouse