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EP-4735895-A1 - HELICOBACTER CAGA PEPTIDES AND THEIR USE IN DIAGNOSIS

EP4735895A1EP 4735895 A1EP4735895 A1EP 4735895A1EP-4735895-A1

Abstract

The invention relates to use of peptides derived from the CagA protein of Helicobacter pylori for improved prevention and prognosis of a vascular or epithelial pathology such as pre-eclampsia and/or other inflammatory conditions, and assessment of such pathologies.

Inventors

  • LUNDIN, Bror Samuel
  • FULURIJA, ALMA
  • MARSHALL, Luke Anthony

Assignees

  • Biotome Pty Ltd

Dates

Publication Date
20260506
Application Date
20240630

Claims (20)

  1. 1 . A method of using at least one peptide sequence derived from a linear epitope of the CagA protein of H. pylori, for the identification of a subject at increased risk of developing pre-eclampsia.
  2. 2. A method of using at least one peptide sequence derived from a linear epitope of the CagA protein of H. pylori as a marker for increased risk of developing preeclampsia in a subject.
  3. 3. A method according to claim 1 or claim 2, wherein the at least one peptide sequence comprises the sequence AKIDQLN (SEQ ID NO 257).
  4. 4. A method according to any one of the previous claims, wherein the at least one peptide sequence comprises any one or more of the following sequences: TQVAKKVNAKIDQLN (SEQ ID NO 236) TQVAKKVKAKIDQLN (SEQ ID NO 239) AQVAKKVSAKIDQLN (SEQ ID NO 240) AQVAKKVNAKIDQLN (SEQ ID NO 241 ) VAKKVSAKIDQLNEA (SEQ ID NO 244) KKVSAKIDQLNQAAS (SEQ ID NO 246) KKVSAKIDQLNEATS (SEQ ID NO 248) KKVNAKIDQLNQIAS (SEQ ID NO 250) KKVNAKIDQLNQAAS (SEQ ID NO 253) VSAKIDQLNEATSAI (SEQ ID NO 254)
  5. 5. A method according to claim 1 or claim 2, wherein the at least one peptide sequence comprises any one or more of the following sequences: RSVSPEPIYATIDDL (SEQ ID NO 284) EPIYATI (SEQ ID NO 574) EPIYAAI (SEQ ID NO 575) EPAYATI (SEQ ID NO 576) EPXYAXI (SEQ ID NO 756)
  6. 6. A method according to claim 1 or claim 2, wherein the at least one peptide sequence comprises any one or more of the following sequences: ENSTEPIYAKVNKKK (SEQ ID NO 223) EPIYAQV (SEQ ID NO 479) EPIYAAV (SEQ ID NO 480) EPIYAKV (SEQ ID NO 487) EPIYAXV (SEQ ID NO 703)
  7. 7. A method according to claim 1 or claim 2, wherein the at least one peptide sequence comprises the sequence KI(X1)QLN, wherein: X1 is a negatively charged amino acid (D or E).
  8. 8. A method according to claims 1 , 2, or 7, wherein the at least one peptide sequence comprises the sequence KIEQLN (SEQ ID NO 396).
  9. 9. A method according to any one of the previous claims, wherein the at least one peptide sequence comprises at most 35 amino acids.
  10. 10. A method according to any one of the previous claims, wherein the at least one peptide sequence comprises no more than 15 amino acids.
  11. 11. A method according to any one of the previous claims, wherein the at least one peptide sequence comprises no more than 8 amino acids.
  12. 12. A method according to any one of the previous claims, wherein the at least one peptide sequence comprises no more than 7 amino acids.
  13. 13. Use of at least one peptide sequence derived from a linear epitope of the CagA protein of H. pylori, for the identification of a subject at increased risk of developing pre-eclampsia.
  14. 14. Use of at least one peptide sequence derived from a linear epitope of the CagA protein of H. pylori as a marker for increased risk of developing pre-eclampsia in a subject.
  15. 15. Use according to claim 13 or claim 14, wherein the at least one peptide sequence comprises the sequence AKIDQLN (SEQ ID NO 257).
  16. 16. Use according to any one of claims 13 to 15, wherein the at least one peptide sequence comprises any one or more of the following sequences: TQVAKKVNAKIDQLN (SEQ ID NO 236) TQVAKKVKAKIDQLN (SEQ ID NO 239) AQVAKKVSAKIDQLN (SEQ ID NO 240) AQVAKKVNAKIDQLN (SEQ ID NO 241 ) VAKKVSAKIDQLNEA (SEQ ID NO 244) KKVSAKIDQLNQAAS (SEQ ID NO 246) KKVSAKIDQLNEATS (SEQ ID NO 248) KKVNAKIDQLNQIAS (SEQ ID NO 250) KKVNAKIDQLNQAAS (SEQ ID NO 253) VSAKIDQLNEATSAI (SEQ ID NO 254)
  17. 17. Use according to claim 13 or claim 14, wherein the at least one peptide sequence comprises any one or more of the following sequences: RSVSPEPIYATIDDL (SEQ ID NO 284) EPIYATI (SEQ ID NO 574) EPIYAAI (SEQ ID NO 575) EPAYATI (SEQ ID NO 576) EPXYAXI (SEQ ID NO 756)
  18. 18. Use according to claim 13 or claim 14, wherein the at least one peptide sequence comprises any one or more of the following sequences: ENSTEPIYAKVNKKK (SEQ ID NO 223) EPIYAQV (SEQ ID NO 479) EPIYAAV (SEQ ID NO 480) EPIYAKV (SEQ ID NO 487) EPIYAXV (SEQ ID NO 703)
  19. 19. Use according to claim 13 or claim 14, wherein the at least one peptide sequence comprises the sequence KI(Xi)QLN, wherein: Xi is a negatively charged amino acid (D or E).
  20. 20. Use according to claims 13, 14, or 19, wherein the at least one peptide sequence comprises the sequence KIEQLN (SEQ ID NO 396).

Description

HELICOBACTER CAGA PEPTIDES AND THEIR USE IN DIAGNOSIS Technical Field [0001 ] This invention relates to peptides from the CagA protein of Helicobacter pylori. The peptides can be used for improved prevention and prognosis of a vascular or epithelial pathology such as pre-eclampsia, and assessment of such pathologies. Background Art [0002] The following discussion of the background art is intended to facilitate an understanding of the present invention only. The discussion is not an acknowledgement or admission that any of the material referred to is or was part of the common general knowledge as at the priority date of the application. [0003] Helicobacter pylori is a bacterium usually found in the stomach. Certain H. pylori strains carry the cagA (cytotoxicity-associated antigen A) gene which encodes a virulence factor. The cagA gene encodes the 1140 to 1180-amino acid protein CagA which is a bacterial oncoprotein that is translocated into stomach epithelial cells at the site of infection. Upon translocation, it affects intracellular signalling pathways of the epithelial cell. Generally, H. pylori- nfected individuals will raise antibodies against H. pylori proteins, including CagA. Thus, the presence of CagA-specific antibodies indicates H. pylori infection. [0004] Pre-eclampsia is a major cause of morbidity and mortality among pregnant women. Pre-eclampsia involves high blood pressure caused by pregnancy and affects around 5% of pregnant women. Around 76,000 women die from the condition each year, as do up to 500,000 babies. Several published studies state a correlation between H. pylori infection in the pregnant mother and risk for pre-eclampsia. For example, a recent meta-analysis which reviewed 31 different research studies, involving 22,800 patients in total, showed a 2.5-fold increased risk of pre-eclampsia in mothers infected with H. pylori compared to uninfected mothers (Zhan et al 2019). In addition, sensitivity analysis on meta-analyses showed a significant association between H. pylori infection and low birthweight (Zhan et al 2019). [0005] A general hypothesis emanating from these studies is that H. pylori infection and its associated chronic inflammation of the stomach somehow causes increased inflammation in the placental blood vessels, which may lead to - or may increase the risk of - pre-eclampsia in a subject. Importantly, there is great variability in the DNA- and protein sequences among different H. pylori isolates. Certain CagA-variants appear to be more strongly associated with pre-eclampsia risk, but no underlying mechanism has been elucidated of which the Applicant is aware. [0006] Unhelpfully, certain detection methods have, in the past, yielded wildly differing results. Depending on the method of assessment, the risk of pre-eclampsia due to H. pylori infection have varied from minor to significant between studies. Specifically, Shiadeh et al (2017) conducted a meta-analysis which indicated that in subgroup analysis, CagA seropositivity was a substantial risk factor for pre-eclampsia when immunoblotting methods (Odds-ratio [OR], 11.12; 95% Cl, 5.34-23.16; 2= 6.42; I2= 53.3%, 95% Cl 0-85) were used, whereas it was not a potential risk factor for pre-eclampsia when ELISA was used as a detecting method (OR, 1.11 ; 95% Cl, 0.6-2.06; x2= 1.83; I2= 0%, 95% Cl 0-90). Currently, Western blot appears to be the most effective method for CagA-antibody analysis, and when it was used the risk of pre-eclampsia in women positive for such antibodies was 11 times higher than in women without the antibodies (OR 11.1). [0007] Therefore, it would be useful to be able to identify one or more risk factors, such as specific H. pylori CagA markers or strain types that are associated with increased risk of pre- eclampsia in subjects and that could provide a more accurate determination of a patient’s risk of developing a vascular or epithelial pathology, such as pre-eclampsia. Moreover, the ability to provide such a determination agnostic of the immune assay utilised would be of great help in producing more accurate diagnosis and potential treatment of subjects that are predisposed to developing a vascular or epithelial pathology, such as pre-eclampsia. [0008] It is therefore an object of this invention to address some of the shortcomings of prior detection systems for identifying subjects with an increased risk of a vascular or epithelial pathology, such as pre-eclampsia. Summary of Invention [0009] Broadly, the invention relates to peptides comprising linear epitopes from CagA+ H. pylori that find use in diagnostic applications related to H. py/or/-associated diseases including, specifically, identification of subjects at an increased risk of developing pathologies of the vascular or epithelial system, such as pre-eclampsia. [0010] The term “linear epitope” or a “sequential epitope” as used herein is an epitope that is recognised by antibodies by its linear sequence of amino acids, or primary structure