Compositions and methods for modifying cell surface glycans

A composition for ex vivo modification of a glycan on the surface of a viable cell or cell particle, the composition comprising:

• a purified glycosyltransferase polypeptide in a physiologically acceptable solution free of divalent metal ions, wherein the glycosyltransferase has unit activity capable of transferring at least 1.0 μmole of sugar per minute at pH 6.5 at 37° C. to an acceptor glycan in a reaction buffer free of divalent metal ions, and
• wherein the glycosyltransferase is a fucosyltransferase, a galactosyltransferase, a sialyltransferase, an N-acetylglucosaminyltransferase, or any combination thereof.

A kit for modifying a glycan on the surface of a cell or cell particle, the kit comprising:

• a purified glycosyltransferase in a physiologically acceptable solution free of divalent metal ions, wherein the glycosyltransferase has unit activity capable of transferring at least 1.0 μmole of sugar per minute at pH 6.5 at 37° C. to an acceptor glycan in a reaction buffer free of divalent metal ions,
• wherein the glycosyltransferase is a fucosyltransferase, a galactosyltransferase, a sialyltransferase, an N-acetylglucosaminyltransferase, or any combination thereof.

An ex vivo method for modifying a glycan on the surface of a viable cell or cell particle, the method comprising:

• contacting a population of cells or cell particles with a sugar donor and an exogenous glycosyltransferase, wherein said modification is performed in a physiologically acceptable solution substantially free of divalent metal ions, wherein the glycosyltransferase has unit activity capable of transferring at least 1.0 μmole of sugar per minute at pH 6.5 at 37° C. to an acceptor glyucan in a reaction buffer free of divalent metal ions,
• wherein the glycosyltransferase is a fucosyltransferase, a galactosyltransferase, a sialyltransferase, an N-acetylglucosaminyltransferase, or any combination thereof.