Synthetic peptides useful in biological essays for detecting infections caused by group O HIV-1 viruses

Synthetic peptide in linear form or in a form cyclized by means of intercysteine disulphide bridges, having the general formula (I):

• Δ-Z-TrpGlyCys-Θ-CysTyrThrSer-Ω
• wherein
• Δ is selected from the group consisting of a biotinyl radical, a biocytinyl radical, a hydrogen atom, an acetyl (CH3CO—) radical, an aliphatic chain which may contain one or two thiol, an aldehyde functional group and an amine functional group,
• Z represents a peptide sequence, selected from the group consisting of the sequences of the formulae:
• -Ser-2 (II)
• 1-Ser (IV)
• -Gln-2 (V)
• 1-Asn-2 (VIII)
• wherein
• 1 represents a peptide sequence of 0 to 9 amino acids, and
• 2 represents a peptide sequence of 0 to 5 amino acids,
• Θ represents a peptide sequence of formula (XI):
• (AA1)-Gly-(AA3)-Leu-(AA5) (XI):
• wherein
• (AA1) is selected from the group consisting of a lysine residue and an arginine residue,
• (AA3) is selected from the group consisting of a lysine residue and an arginine residue,
• (AA5) is selected from the group consisting of an isoleucine residue and a valine residue, provided, however, that Θ never represents the peptide sequence Lys Gly Lys Leu Ile or Lys Gly Lys Leu Val,
• Ω attached to the —CO— group of serine, is selected from the group consisting of:
• a hydroxyl (—OH) radical and
• a peptide sequence of formula (XII):
• Val-Σ-Ψ (XII)
• wherein Σ represents a sequence:
• (AA6)-Trp Asn-(AA7)-(AA8) (XIII)
• wherein:
• (AA6) represents an amino acid different from lysine,
• (AA7) represents an amino acid,
• (AA8) is selected from the group consisting of a serine and a threonine residue, and Ψ, attached to the —CO— residue of the free AA8 amino acid, is selected from the group consisting of an OH group and a NH2 group.