Immunohistochemical Localization of Haptoglobin in Porcine Salivary Gland and Diaphragm

The up-regulation of ferritin heavy chain (FHC) is reported in six papillary and in four invasive urothelial tumours of the urinary bladder of cattle grazing on mountain pastures rich in bracken fern. All tumours contained sequence of bovine papillomavirus type-2 (BPV-2) as determined by polymerase chain reaction (PCR) analyses and validated by direct sequencing of the amplified products. The oncoprotein E5 was also detected in these tumours by immunoprecipitation and by immunofluorescence and laser scanning confocal microscopy. Expression of FHC was evaluated by western blot analysis, reverse transcriptase (RT) PCR, real-time RT-PCR and immunohistochemistry. The oligonucleotide sequence of the bovine ferritin amplicons was identical to that of human ferritin. Nuclear overexpression of p65, an important component of nuclear factor κB (NF-κB) transcription factors, was also observed. These findings suggest that FHC up-regulation may be mediated by activation of NF-κB and that in turn this may be related to the resistance of bovine papillomavirus type-2 (BPV-2) infected urothelial cells to apoptosis.