Figure 6.

Proliferation of IgM⁺, IgD⁺, and IgT⁺ cells in kidney. (A) Confocal microscopic images of rainbow trout kidney sections infected with Tetracapsuloides bryosalmonae exhibiting different swelling grades were labeled with anti-immunoglobulin (Ig) M, anti-IgD, or anti-IgT (green) in combination with anti-proliferating cell nuclear antigen (PCNA) (red). All sections were also counterstained with DAPI (blue). Representative images for grade 0 and grade 2 are shown (scale bars = 20 µm) along with representative images from grade 2 kidneys at higher magnification (right; scale bars = 5 µm). Note that in non-proliferating cells, nuclei appear blue whereas they appear violet in proliferating cells. Mean number (B) and mean percentage (C) of proliferating IgM⁺, IgD⁺, and IgT⁺ cells were calculated in 10 digital fields (400× magnification) from 6 different individuals. Statistically significant differences (P < 0.05) in proliferating IgM⁺, IgD⁺, and IgT⁺ cells between grade 0 and grade 2 fish (analyzed by one-way ANOVA followed by two-tailed Student’s t-test) are indicated with an asterisk.