Fig. 6.

Proliferation of IgM⁺ and ZAP70⁺ cells in kidney 15 and 30 days after the anal administration of antigens. Confocal microscopy images of rainbow trout kidney sections obtained from fish anally immunized with the different antigens at days 15 (A) and 30 (D) post-immunization. Sections were labeled with anti-IgM (green), or anti-ZAP70 (green) in combination with anti-proliferating cell nuclear antigen (PCNA) (red). All sections were also counterstained with DAPI (blue). Representative images of each condition are shown (scale bars = 20 μm) along with representative images from TNP-LPS immunized spleens 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, E) and mean percentage (C, F) of proliferating IgM⁺ and ZAP70⁺ cells were calculated in 10 digital fields (400 × magnification) from at least 4 different individuals. Asterisks denote significantly different values between indicated groups (*p ≤ 0.05 and ***p ≤ 0.005). (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)