Immunogenicity, protective efficacy and preliminary protective mechanism of KPC-2, a drug resistance target from Klebsiella pneumoniae
10.3760/cma.j.cn112309-20231129-00154
- VernacularTitle:肺炎克雷伯菌耐药靶标KPC-2的免疫原性和保护效果评价及保护机制初步研究
- Author:
Xiaoqiong WANG
1
;
Guangyang MING
;
Zhifu CHEN
;
Qiang GOU
;
Yue YUAN
;
Liqun ZHAO
;
Jinyong ZHANG
;
Renjian HU
Author Information
1. 重庆理工大学药学与生物工程学院，重庆 400054
- Keywords:
Klebsiella pneumoniae;
KPC-2;
Bacterial drug resistance;
Vaccine
- From:
Chinese Journal of Microbiology and Immunology
2024;44(1):2-10
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To develop a recombinant protein vaccine based on KPC-2, a drug resistance target in Klebsiella pneumoniae, and evaluate its immunogenicity, protective efficacy and mechanism in a mouse model of pneumonia. Methods:KPC-2 was expressed in Escherichia coli and purified using GST affinity chromatography. A recombinant protein vaccine was prepared with KPC-2 and used to immunize New Zealand rabbits through subcutaneous injection. Serum samples were isolated from cardiac blood and Protein G chromatography was used to purify polyclonal antibodies against KPC-2. Opsonophagocytic killing assay was used to assess the bactericidal activity of the polyclonal antibodies in vitro. Female BALB/c mice were immunized three times with the recombinant protein vaccine, and the titers of specific IgG antibodies in serum were measured by indirect ELISA. One week after the last vaccination, the mice were infected with Klebsiella pneumoniae strain SRT through tracheal intubation, and received a single intravenous dose of meropenem (0.1 mg) 1 h later. The protective efficacy of the KPC-2 recombinant protein vaccine was evaluated by comparing the survival rates, bacterial colonization and histopathological changes between vaccine group and adjuvant group as well as the survival rates between meropenem group and normal saline group. Moreover, the protective efficacy of polyclonal antibodies against KPC-2 was evaluated through passive immunization. Results:The level of specific IgG antibodies in serum was significantly higher in the vaccine group than in the adjuvant group ( t=4.325, P<0.05). The survival rate in the vaccine group was also higher than that of the adjuvant group [70% (7/10) vs 10% (1/10), P<0.05]. Furthermore, lung inflammation was less severe and bacterial burden was reduced in the vaccine group as compared with those of the control group ( t=3.127, P<0.05). Both active and passive vaccination strategies demonstrated strong protective efficacy against Klebsiella pneumoniae infection, and had a synergistic effect when used in combination with antibiotic therapy. The polyclonal antibodies against KPC-2 had bactericidal activity in vitro ( t=5.427, P<0.05). Conclusions:The prepared KPC-2 vaccine has better immunogenicity and protective efficacy. It can induce strong humoral immune responses. This study suggest that drug resistance target may be used as a candidate antigen for future vaccine development.
