In Vitro: In a northern blot analysis, pBD-1 TFA mRNA only expresses in ongue epithelial tissues from 4-5 week old pigs.In RT-PCR analysis, pBD-1 TFA message throughout the epithelia of the respiratory (from nasal septum to lung) and gastrointestinal (from esophagus to rectum) tracts. In addition, it is detected in thymus, spleen, lymph node, brain, liver, kidney, urinary bladder, testis, skin, heart, muscle, bone marrow, alveolar macrophages, peripheral blood neutrophils and the umbilical cord. The only cells evaluated that does not express pBD-1 TFA are peripheral blood mononuclear cells.