Fig. 4
IL-17 expression in synovial tissues. a Histological sections of representative B10.RIII mice displaying IL-17 expression in the four mouse groups. Left column shows low magnification (×4). Right column shows a higher magnification (×40) of the respective boxed areas shown in the left column. Group II paws had severe joint tissue-invading pannus tissue, which was heavily infiltrated by IL-17-exprescsing cells. b Immunofluorescence. Representative images of the joint tissues from different treatment groups. Blue staining represents 4′ 6-diamidino-2-phenylindole; red fluorescence represents IL-17. The calculated percentage of IL-17-positive cells is shown in the right upper corner of each image. Group II paws had much higher abundance of IL-17-expressing cells compared to the three other groups. Group III had an intermediate level of IL-17 abundance. c (i), (ii), (iii), (iv) Representative fluorescence in situ hybridization images of c (i) P. gingivalis/T. denticola/T. forsythia (Pg/Td/Tf)-infected mice with no presence of bacteria, c (ii) the presence of P. gingivalis (bright red fluorescence denoted by white arrowheads) in ankle joint tissue of mice infected with Pg/Td/Tf along with collagen immunized in B10.RIII mice, c (iii) collagen control infected mice with no presence of bacteria, c (iv) sham-infected mice with no presence of bacteria. Scale bar represents 10 μm