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

Esther Yip-Mei Liu, Jiun-Han Chen, Jung-Chung Lin, Ching-Hsun Wang, Chang-Phone Fung, Yi-Jiun Ding, Feng-Yee Chang, L Kristopher Siu

Vaccine 2022 Apr 20

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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. Copyright © 2022 Elsevier Ltd. All rights reserved.

Citation

Esther Yip-Mei Liu, Jiun-Han Chen, Jung-Chung Lin, Ching-Hsun Wang, Chang-Phone Fung, Yi-Jiun Ding, Feng-Yee Chang, L Kristopher Siu. Cross-protection induced by highly conserved outer membrane proteins (Omps) in mice immunized with OmpC of Salmonella Typhi or OmpK36 of Klebsiella pneumoniae. Vaccine. 2022 Apr 20;40(18):2604-2611