Polyribonucleotide containing deuterated nucleotides

A method for preparing a polyribonucleotide comprising a sequence which encodes a protein, comprising using deuterated adenosine, cytidine, guanosine, and uridine nucleotides and modified forms thereof for the preparation of said polyribonucleotide, wherein said polyribonucleotide shows reduced immunogenicity and/or enhanced expression compared to a polyribonucleotide comprising the same sequence but without said deuterated nucleotides, wherein at least 25% of each adenosine, cytidine, guanosine, and uridine nucleotides are deuterated in the polyribonucleotide.

A method for reducing the immunogenicity and/or enhancing the expression of a polyribonucleotide comprising a sequence which encodes a protein, comprising:

• incorporating deuterated adenosine, cytidine, guanosine, and/or uridine residues within said polyribonucleotide, wherein said polyribonucleotide thus obtained displays reduced immunogenicity and/or enhanced expression compared to a polyribonucleotide comprising the same sequence but without said deuterated nucleotides, wherein at least 25% of each adenosine, cytidine, guanosine, and uridine nucleotides are deuterated in the polyribonucleotide.

An isolated polyribonucleotide comprising a sequence which encodes a protein, wherein at least 25% of at least two types of nucleotides selected from the group consisting of adenosine, cytidine, guanosine, and uridine are deuterated, wherein the expression of said polyribonucleotide is enhanced compared to a polyribonucleotide comprising the same sequence but without said deuterated nucleotides.