Tetranectin-like protein in vertebrate serum: a comparative immunochemicalanalysis

The glycoprotein tetranectin (TN) found in human serum is a 90-kDa homotrim eric C-type lectin binding Ca2+ heparin and plasminogen kringle 4. TN is su ggested as being implicated in tissue remodelling. The antigenic reactivity of putative TN was examined in serum from 14 different animal species usin g three sandwich enzyme immunoassays for human TN. Crab-eating macaque seru m showed the strongest reaction, followed by horse and cat. Serum from cow, goat, pig, mouse and chicken reacted weakly, while dog, trout, and the amp hibian and the reptile species did not react. The TN-like protein from maca que, horse and cat serum bound heparin and showed the same dependence on Ca 2+ for interaction with the monoclonal antibodies as human TN. Gel filtrati on of sera from the three animal species showed that the TN-like protein el uted as single peaks with a M-r of 70-90 kDa. Western blotting of horse and cat TN-like protein electrophoresed under reducing conditions showed that the antibodies against human TN reacted with a single band with an approxim ate M-r of 30 kDa, indicating that the TN-like protein is also a homotrimer . Horse and cat TN-like protein interacted with human kringle 4-sepharose. Most likely, the reacting protein represents crab-eating macaque, horse and cat homologues of human TN. (C) 2001 Elsevier Science Inc. All rights rese rved.