Pseudotype formation is a powerful tool for analysing mechanisms of virus neutralization and entry, since it allows for analysis of glycoprotein properties without the necessity for preparing recombinant genomes. Using recombinant vaccinia viruses, we prepared pseudotypes of La Crosse virus with recombinant glycoproteins cloned from the monoclonal antibody (MAb)-resistant variant V31. The resulting pseudotypes became partially resistant to MAb 807-31. Furthermore, when the V31 glycoproteins were incorporated into a second MAb-resistant variant (V33), the pseudotyped virus became sensitive to neutralization by the MAb (807-33) originally used in its selection. These results suggest a simple technique for the incorporation of glycoprotein mutations into bunyaviruses, allowing analysis of mechanisms of neutralization and other virus entry functions.