Mgat1-deficient cells for production of vaccines and biopharmaceutical products

Mannosyl (alpha-1,3)-glycoprotein beta-1,2-N-Acetylglucosaminyltransferase (Mgat1)-deficient cell lines and methods for use of same for producing human immunodeficiency virus (HIV) envelope glycoprotein polypeptides or fragment thereof with terminal mannose-5 glycans are provided.