We immunized rats with recombinant murine osteopontin protein and obtained
four monoclonal antibodies recognizing distinct epitopes of murine osteopon
tin. OPN1.2 recognized the amino-terminal half of OPN, while OPN2.2, OPN2.3
, and OPN3.1 recognized the carboxy-terminal half of OPN. The epitope recog
nized by OPN2.2 was destroyed by further cleavage of the carboxy half of OP
N. The epitope recognized by OPN2.3 was located in the amino-terminal end o
f the carboxy half of OPN, whereas that recognized by OPN3.1 was located in
the carboxy-terminal end of the carboxy half of OPN. OPN1.2 and OPN2.2 rec
ognized thrombin-cleaved osteopontin, whereas thrombin-cleaved osteopontin
was not recognized by OPN2.3 and OPN3.1. Thus, these monoclonal antibodies
will be useful in structure/function studies of the role of osteopontin in
murine models of disease. (C) 1999 Academic Press.