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

1. Synthetic peptides in linear form, or cyclized by means of inter-cysteine disulphide bridges, having the general formula (I):

Δ-Z-Trp Gly Cys (residues 5 to 7 of SEQ ID NO: 1)-Θ-Cys Tyr Thr Ser (residues 13 to 16 of SEQ ID NO: 1)-Ω  (I)

wherein:

Δ is selected from the group consisting of a biotinyl radical, a biocytinyl radical, a hydrogen atom, an acetyl (CH 3 CO—) radical, an aliphatic chain which may contain one or two thiol, an aldehyde functional group and an amine functional group,

Z is a peptide sequence selected from the group consisting of:

Leu Leu Ser Ser (residues 1 to 4 of SEQ ID NO: 3),

Leu Leu Asn Ser (residues 1 to 4 of SEQ ID NO: 6),

Arg Leu Asn Ser (residues 1 to 4 of SEQ ID NO: 16),

Ala Leu Glu Thr Leu Leu Gln Asn Gln Gln Leu Leu Asn Ser (residues 1 to 14 of SEQ ID NO: 11),

Ala Leu Glu Thr Leu Leu Gln Asn Gln Gln Leu Leu Asp Leu (residues 1 to 14 of SEQ ID NO: 13),

Ala Leu Glu Thr Leu Leu Gln Asn Gln Gln Leu Leu Asn Ile (residues 1 to 14 of SEQ ID NO: 12),

Leu Asn Gln Gln Arg Leu Leu Asn Ser (residues 1 to 9 of SEQ ID NO: 14), and

Arg Ala Leu Glu Thr Leu Leu Asn Gln Gln Arg Leu Leu Asn Ser (residues 1 to 15 of SEQ ID NO: 15),

Θ is a peptide sequence selected from the group consisting of:

Arg Gly Arg Leu Val (residues 8 to 12 of SEQ ID NO: 2),

Arg Gly Lys Leu Ile (SEQ ID NO: 17),

Arg Gly Lys Leu Val (SEQ ID NO: 18), and

Lys Gly Arg Leu Val (residues 8 to 12 of SEQ ID NO: 3),

Ω, attached to the —CO— group of Ser, is selected from the group consisting of:

a hydroxyl group and

a peptide sequence of formula

Val-Ψ,

Val Arg Trp Asn Glu Thr-Ψ(residues 27-32 of SEQ ID NO: 11),

Val Gln Trp Asn Glu Thr-Ψ(residues 27 to 32 of SEQ ID NO: 1), and

Val Gln Trp Asn Ser Thr-Ψ(residues 27 to 32 of SEQ ID NO: 4),

wherein Ψ, attached to the —CO— residue of Val or Thr, is selected from the group consisting of a OH group, a NH 2 group, and an alkoxy radical comprising from 1 to 6 carbon atoms.

2. Synthetic peptides of formula (I) according to claim 1 wherein Δ represents an aliphatic chain, said aliphatic chain being selected from the group consisting of an alkyl chain of 1 to 6 carbon atoms, an alkenyl chain of 2 to 6 carbon atoms, and an aminoalkylcabonyl chain of 2 to 6 carbon atoms.

3. Synthetic peptides of formula (I) according to claim 1 including one of the following sequences:

LLSLWGCRGRLVCYTSVQWNET or

Leu Leu Ser Leu Trp Gly Cys Arg Gly Arg Leu Val Cys Tyr Thr Ser Val Gln Trp Asn

 1                5                  10                  15                  20

Glu Thr (SEQ ID NO: 2),

    22

LLSSWGCKGRLVCYTSVQWNET or

Leu Leu Ser Ser Trp Gly Cys Lys Gly Arg Leu Val Cys Tyr Thr Ser Val Gln Trp Asn

 1                5                  10                  15                  20

Glu Thr (SEQ ID NO: 3),

    22

LLSSWGCKGRLVCYTSVQWNST or

Leu Leu Ser Ser Trp Gly Cys Lys Gly Arg Leu Val Cys Tyr Thr Ser Val Gln Trp Asn

 1                5                  10                  15                  20

Ser Thr (SEQ ID NO: 4),

    22

LLQSWGCKGRLVCYTSVQWNST or

Leu Leu Gln Ser Trp Gly Cys Lys Gly Arg Leu Val Cys Tyr Thr Ser Val Gln Trp Asn

 1                5                  10                  15                  20

Ser Thr (SEQ ID NO: 5),

    22

LLSSWGCRGRLVCYTSVQWNET or

Leu Leu Ser Ser Trp Gly Cys Arg Gly Arg Leu Val Cys Tyr Thr Ser Val Gln Trp Asn

 1                5                  10                  15                  20

Glu Thr (SEQ ID NO: 8),

    22

LLSSWGCKGRLVCYTS or

Leu Leu Ser Ser Trp Gly Cys Lys Gly Arg Leu Val Cys Tyr Thr Ser (SEQ ID NO: 9),

 1                5                  10                  15

LLNSWGCKGRLVCYTS or

Leu Leu Asn Ser Trp Gly Cys Lys Gly Arg Leu Val Cys Tyr Thr Ser (SEQ ID NO: 10),

 1                5                  10                  15

ALETLLQNQQLLNSWGCRGRLVCYTSVRWNET or

Ala Leu Glu Thr Leu Leu Gln Asn Gln Gln Leu Leu Asn Ser Trp Gly Cys Arg Gly

 1                5                  10                  15

Arg Leu Val Cys Tyr Thr Ser Val Arg Trp Asn Glu Thr (SEQ ID NO: 11),

 20                  25                  30

ALETLLQNQQLLNIWGCRGRLVCYTSVRWNET or

Ala Leu Glu Thr Leu Leu Gln Asn Gln Gln Leu Leu Asn Ile Trp Gly Cys Arg Gly

 1                5                  10                  15

Arg Leu Val Cys Tyr Thr Ser Val Arg Trp Asn Glu Thr (SEQ ID NO: 12),

 20                  25                  30

ALETLLQNQQLLDLWGCRGRLVCYTSVRWNET or

Ala Leu Glu Thr Leu Leu Gln Asn Gln Gln Leu Leu Asp Leu Trp Gly Cys Arg Gly

 1                5              10                  15

Arg Leu Val Cys Tyr Thr Ser Val Arg Trp Asn Glu Thr (SEQ ID NO: 13),

 20                  25                  30

LNQQRLLNSWGCKGRLVCYTSV or

Leu Asn Gln Gln Arg Leu Leu Asn Ser Trp Gly Cys Lys Gly Arg Leu Val Cys Tyr

 1                5                  10                  15

Thr Ser Val (SEQ ID NO: 14),

 20

RALETLLNQQRLLNSWGCKGRLVCYTSV or

Arg Ala Leu Glu Thr Leu Leu Asn Gln Gln Arg Leu Leu Asn Ser Trp Gly Cys Lys

 1                5                  10                  15

Gly Arg Leu Val Cys Tyr Thr Ser Val (SEQ ID NO: 15),

 20                  25

RLNSWGCKGRLVCYTSV or

Arg Leu Asn Ser Trp Gly Cys Lys Gly Arg Leu Val Cys Tyr Thr Ser Val (SEQ ID NO: 16).

 1                5                  10                  15

4. Composition containing at least one synthetic peptide of formula (I) according to claim 1 , said peptide being freeze-dried or diluted in water.

5. Composition according to claim 4 containing, as the at least one synthetic peptide of formula (I), SEQ ID NO: 3 and SEQ ID NO: 1.

6. Composition containing at least one synthetic peptide of formula (I) according to claim 1 and at least one group O HIV-1 recombinant peptide.

7. Composition containing at least one synthetic peptide of formula (I) according to claim 1 , and at least one HIV-1 and/or HIV-2 recombinant or synthetic peptide.

8. Immunoassay method for detecting a group O HIV-1 infection comprising the steps of

a) obtaining a sample from a patient likely to contain anti-group O HIV-1 antibodies:

b) contacting at least one synthetic peptide of formula (I) according to claim 1 , detectably labeled, with said sample;

c) detecting the presence or absence of a complex between said peptides and said antibodies;

d) optionally assaying the amount of said antibodies in the sample; wherein the presence of a complex between said peptides and said antibodies is indicative of a group O HIV-1 infection.

9. Immunoassay method for detecting a group O HIV-1 infection comprising the steps of:

a) obtaining a sample from a patient likely to contain anti-group O HIV-1 antibodies;

b) contacting a composition according to claim 4 , containing at least one synthetic peptide of formula (I), delectably labeled, with said sample:

c) detecting the presence or absence of a complex between said peptides and said antibodies; and

d) optionally assaying the amount of said antibodies in the sample;

wherein the presence of a complex between said peptides and said antibodies is indicative of a group O HIV-1 infection.

10. Diagnostic kit for the detection of group O HIV-1 specific antibodies comprising

a) a first container comprising at least one synthetic peptide of formula (I) according to claim 1 and

b) second container comprising appropriate means of detection of complexes between said antibodies and said peptide.

11. Diagnostic kit for the detection of group O HIV-1 specific antibodies comprising

a) first container comprising a composition according to claim 4 and

b) a second container comprising appropriate means of detection of complexes between said antibodies and said peptide.