Date of Award
Doctor of Philosophy
Veterinary Microbiology and Preventive Medicine
James A. Roth
The cDNA clones encoding for the bovine glycoproteins CD44 and LECAM-1 (lectin cell adhesion molecule-1) were isolated and sequenced. The predicted amino acid sequences of bovine CD44 and LECAM-1 had high identities with those of human and murine CD44 and LECAM-1. The high identities of the predicted amino acid sequences of these glycoproteins in the bovine, human and mouse suggest they may have similar functions in all three species. While the overall amino acid identities were high, bovine CD44 had an area of low identity with human and murine CD44 in the extracellular domain and the cytoplasmic tail of bovine LECAM-1 had low identity with the cytoplasmic tails of human and murine LECAM-1;Human CD44 has been previously reported to be involved in the recirculation or homing of human lymphocytes to high-walled endothelial venules (HEV) in lymphoid tissue. While the predicted amino acid sequence of bovine CD44 was determined to be similar to human CD44, the role of bovine CD44 in lymphocyte homing was not determined in this study;Bovine LECAM-1, like human and murine LECAM-1, contained a lectin domain that likely controls the homing of peripheral lymphocytes as fructose-1-phosphate and fucoidin blocked the binding of bovine lymphocytes to peripheral lymph node HEV. Neuraminidase and phorbol myristate acetate treatments affected the binding of bovine, human, and murine lymphocytes to murine peripheral lymph node HEV in a similar manner in all three species. A monoclonal antibody that recognizes human LECAM-1 blocked the binding of bovine lymphocytes to peripheral lymph node HEV, but not Peyer's patch HEV. Expression of bovine LECAM-1 was high in peripheral lymph nodes and low in Peyer's patches. These data strongly suggest that LECAM-1 is an evolutionarily conserved molecule and that bovine LECAM-1, like human and a murine LECAM-1, is a peripheral lymphocyte homing receptor.
Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/
Brad Thomas Bosworth
Bosworth, Brad Thomas, "Molecular mechanisms controlling bovine lymphocyte homing " (1991). Retrospective Theses and Dissertations. 9605.