Glycan-masked engineered outer domains of HIV-1 gp120 and their use

An isolated immunogen, comprising:

• an engineered gp120 outer domain, comprising an amino acid sequence according to SEQ ID NO:
• 1 further comprising amino acid substitutions, insertions, and/or deletions as follows:
• amino acid substitutions to introduce N-linked glycan sequons beginning at one or more of residues 8, 14, 56, 70, 71, 74, 102, and 153 of SEQ ID NO:
• 1, wherein a glycine insertion is introduced between residues 10 and 11 if the N-linked glycan sequon beginning at residue 8 is introduced, and an E70G substitution is introduced if the N-linked glycan sequon beginning at residue 71 is introduced, and optionally a GG substitution for the residues at positions corresponding to positions 70 and 71 of SEQ ID NO:
• 1 if N-linked glycan sequons beginning at residue 70 or 71 are not introduced;
• and
• wherein:
• the engineered gp120 outer domain comprises N-linked glycan sequons beginning at residues corresponding to residues 18, 65, 92, 98, 106, 113, 129, 146, 165, and 170 of SEQ ID NO:
• 1;
• the residues of the engineered gp120 outer domain corresponding to residues 25-45, 79-85, and 126-145 of SEQ ID NO:
• 1 are identical to SEQ ID NO:
• 1;
• and
• the remaining residues of the engineered gp120 outer domain comprise an amino acid sequence at least 90% identical to the corresponding residues of SEQ ID NO:
• 1.