Cross-protection induced by highly conserved outer membrane proteins (Omps) in mice immunized with OmpC of Salmonella Typhi or OmpK36 of Klebsiella pneumoniae

• Published in: Vaccine Vol. 40; no. 18; pp. 2604 - 2611
• Main Authors: Liu, Esther Yip-Mei, Chen, Jiun-Han, Lin, Jung-Chung, Wang, Ching-Hsun, Fung, Chang-Phone, Ding, Yi-Jiun, Chang, Feng-Yee, Siu, L. Kristopher
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 20.04.2022; Elsevier Limited
• Subjects: Abscesses; Amino acids; Animals; Antibiotics; Antibodies; Antigens; Bacterial Proteins; Conserved sequence; Cross-protection; Drug resistance; Enterobacteriaceae; Homogenization; Homology; Immunization; K. pneumoniae; Klebsiella; Klebsiella pneumoniae; Klebsiella pneumoniae - metabolism; Membrane proteins; Membranes; Meningitis; Mice; Mice, Inbred BALB C; Nervous system; Nosocomial infections; OmpC; OmpK36; Outer membrane proteins; Porins; Proteins; S. Typhi; Salmonella; Salmonella typhi; Statistical analysis; Vaccination; Vaccines; United States > US; K. pneumoniae; OmpC; S. Typhi; Vaccination; OmpK36
• ISSN: 0264-410X; 1873-2518
• DOI: 10.1016/j.vaccine.2022.03.016

Outer membrane proteins (Omps) are a family of proteins that are highly conserved throughout the evolution of Enterobacteriaceae. Previous studies using sequence comparisons have found a high degree of sequence homology between OmpK36 of Klebsiella pneumoniae and OmpC of Salmonella enterica serovar Typhi. Whether highly conserved OmpC can be directly extrapolated as a common vaccine candidate against K. pneumoniae or other Enterobacteriaceae remains to be verified. OmpK36 and OmpC were purified and used to immunize BALB/c mice. After immunization, five mice from each group were injected intraperitoneally with a cell suspension of K. pneumoniae or S. Typhi, and the mice were monitored daily for 14 days to measure the severity of illness and assess their survival. Cross-reacting OmpK36 and OmpC antibodies were identified in the mice immunized with OmpK36 or OmpC. No cross-protection was observed in the mice immunized with OmpC in the presence of K. pneumoniae infection. Although a high degree of similarity was observed for the amino acid sequences between OmpK36 and OmpC, our results suggested that no cross-protection occurred in the mice challenged with other species.