Table 1.
Main OMPs and their receptors and functions
| OMPs | Gene no. | Protein length (amino acids) | Receptors identified | Localization | Suggested function |
|---|---|---|---|---|---|
| BabA (HopS) | 26695:1243 | 733 | Lewis B blood group antigens [19] | Gastric epithelia | Adhesion to host cell, enhancing translocation of CagA via the T4SS |
| Terminal fucose residues on blood group O (H antigen), A and B antigens salivary nonmucin glycoprotein [89, 90] | Gastric epithelia | ||||
| Salivary mucin MUC5B and proline-rich glycoprotein [90] | Saliva | ||||
| Proline-rich glycoprotein containing Fucα1-2Galβ motif [90] | Saliva | ||||
| Secretory immunoglobulin A containing fucose-oligosaccharide motifs [91, 92] | Saliva | ||||
| Salivary agglutinin DMBT1 [93] | Saliva | ||||
| Mucin MUC5AC with N-Acetylgalactosamine-β-1,4-nacetylglucosamine [94, 95] | Gastric mucus | ||||
| Mucin MUC1 [96] | Gastric mucus | ||||
| Mucin MUC2 [97] | Gastric mucus | ||||
| SabA (HopP) | 26695:0725 | 653 | Sialyl-Lewis X, sialyl-Lewis A, Lewis X [37] | Gastric epithelia | Establishment of the T4SS to enhance inflammatory response |
| Salivary mucin MUC7, MUC5B [90, 98] | Saliva | ||||
| Salivary glycoproteins (carbonic anhydrase VI, secretory component, heavy chain of secretory IgA1, parotid secretory protein, zinc α2 glycoprotein) [90] | Saliva | ||||
| Sialylated moieties on the extracellular matrix protein laminin [98] | Gastric epithelia | ||||
| Sialylated structures on the surface of erythrocytes [99] | Erythrocytes | ||||
| Sialylated carbohydrates on neutrophils [100] | Neutrophils | ||||
| HopQ | 26695:1177 | 641 | CEACAMs family [58, 101] | Leukocytes, granulocytes, endothelial and epithelial cells. | Adhesion to host cell, translocation of CagA via the T4SS |
| OipA (HopH) | 26695:0638 | 305 | Not clear | Not clear | Adhesion, induction of inflammatory cytokine production [44] |
| HopZ | 26695:0009 | 672 | Not clear | Not clear | Involved in adhesion |
| HomB | J99:0870 | 669 | Not clear | Not clear | HomB promotes the secretion of proinflammatory cytokine IL-8 and increases the adhesion to host cells |
OMPs, outer membrane proteins; T4SS, type IV secretion system; MUC, mucin; CEACAM, carcinoembryonic antigen–related cell adhesion molecule; IL-8, interleukin-8