Immunolocalisation of BPTI-like serine proteinase inhibitory proteins in mast cells, chondrocytes and intervertebral disc fibrochondrocytes of ovine and bovine connective tissues. An immunohistochemical and biochemical study

A polyclonal anti-bovine pancreatic trypsin inhibitor (BPTI) IgY was raised in chickens immunised with aprotinin The anti-BPTI IgY was subsequently is olated lated from egg yolks and purified to homogeneity by affinity chromat ography on immobilised aprotinin and by Superose 6 size exclusion fast prot ein liquid chromatography (FPLC). Immunoblotting with the chicken IgY demon strated its specificity for BPTI; 3.9 ng BPTI could be detected by this tec hnique. There was no crossreactivity against alpha(1)-proteinase inhibitor (human and sheep), inter-alpha-trypsin inhibitor (human and sheep), secreto ry leucocyte proteinase inhibitor or a range of serine proteinase inhibitor y proteins (SPIs) isolated from plant sources (soybean and lima bean trypsi n inhibitor, potato trypsin and chymotrypsin inhibitors) or serum SPIs (ant ithrombin-III. alpha(2)-macroglobulin). Immunoblotting using the anti-BPTI IgY identified the 6- to 12- and 58-kDa forms of endogenous ovine cartilage SPIs in cartilage extracts, confirming the interrelationship of the ovine cartilage SPIs with BPTI. BPTI-domain SPIs were immunolocalised within mast cells of ovine and bovine duodenum, lung and pancreas, and in ovine and bo vine bronchial cartilage chondrocytes, chondrocytes of the superficial and intermediate zones of articular cartilage and in the fibrochondrocytes/chon drocytes of the nucleus pulposus and annulus fibrosus of the ovine interver tebral disc.