Analysis of Protegrin-1 Expression in Pigs By RT-PCR, Western Blot and IHC

Protegrins, short cysteine-rich β-sheet antimicrobial peptides with cathelicidin like domain, were first isolated from pig leukocytes. A number of studies reports that protegrins have antimicrobial activity on a broad spectrum of microorganisms including bacteria, fungi and some enveloped viruses. We analyzed protegrin-1 (PG-1) expression in pigs by RT-PCR from 15 pig tissues including cerebrum, eye, cornea, lung, trachea, thymus, spleen, stomach, small intestine, liver, kidney, uterus, ovary, skin and peripheral blood mononuclear cells. We also developed the affinity-purified anti PG-1 polyclonal antibodies which were raised against recombinant PG-1 peptides. The specificity of antibodies was confirmed by the western blot analysis. The results were consistent between RT-PCR and western blot analyses. We performed the immuno-histochemical analysis of PG-1 against pig tissues showing higher levels of PG-1 expression, and identified the PG-1 expressing cells in several pig tissues.  PG-1 expression was confirmed from neutrophils and eosinophils in spleens and livers, leydig cells in testes, the bronchial epithelium of lungs and the columnar epithelium of minor calyx and transitional epithelium cells in kidneys. These results provide insights on the cellular expression pattern of PG-1 in various pig tissues and lead to further understanding of the function of PG-1 for the innate immune system of pigs.