Immunoprotective effect of recombinant peptidyl-prolyl cis-trans isomerase from Babesia microti against B. microti infection in mice
10.16250/j.32.1374.2022226
- VernacularTitle:田鼠巴贝虫肽基脯氨酸异构酶重组蛋白免疫保护效果
- Author:
Yu-chun CAI
1
;
Peng SONG
1
;
Mu-xin CHEN
1
;
Jia-hui SUN
1
;
Yan ZHOU
1
;
Lin LIN
1
;
Jia-xu CHEN
1
Author Information
1. National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research); WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases, Ministry of Science and Technology; National Health Commission Key Laboratory of Parasite and Vector Biology, Shanghai 200025, China
- Publication Type:Journal Article
- Keywords:
Babesiosis;
Babesia microti;
Peptidyl-prolyl cis-trans isomerase;
Immunoprotection;
Cytokine
- From:
Chinese Journal of Schistosomiasis Control
2022;34(6):604-610
- CountryChina
- Language:Chinese
-
Abstract:
Objective To evaluate the immunoprotective effect of active immunization with recombinant peptidyl-prolyl cis-trans isomerase from Babesia microti against B. microti infection in mice. Methods Female BALB/c mice at 6 weeks of age, each weighing approximately 20 g, were divided into the recombinant protein immunization group, the infection control group and the normal control group, of 25, 18, 15 mice in each group, respectively. Mice in the recombinant protein immunization group were given active immunization with recombinant BmPPIase protein, and 18 mice with the highest antibody titers were intraperitoneally injected with 100 μL of B. microti-infected whole blood 2 weeks after the last immunization. Mice in the infection control group were intraperitoneally injected with 100 μL of B. microti-infected whole blood, while 15 mice in the normal control group received no treatment. Blood samples were collected from mice in the recombinant protein immunization group and the infection control group on days 0 to 30 post-immunization for detection of B. microti infection, and blood samples were collected on days 0, 7, 14, 21, and 28 post-immunization for routine blood tests with a blood cell analyzer and for detection of serum cytokines using cytometric bead array. Results Anti-BmPPIase antibodies were detected in 25 mice in the recombinant protein immunization group 2 weeks after the last immunization, with titers of 5 × 103 to 8 × 104. B. microti infection rate peaked in mice in both the recombinant protein immunization and the infection control group on day 7 post-immunization, with positive infection rates of 13.3% and 50.0%, and there were significant differences between the two groups in terms of B. microti infection rate on days 3 (χ2= 113.18, P < 0.01), 5 (χ2 = 475.22, P < 0.01), 7 (χ2 = 465.98, P < 0.01) and 9 post-infection (χ2= 18.71, P < 0.01), while the B. microti infection rate tended to be 0 in both groups on day 11 post-immunization. Routine blood tests showed higher red blood cell counts [(5.30 ± 0.50) × 1012 to (9.87 ± 0.24) × 1012 counts/L)] and hemoglobin levels [(89.67 ± 22.80) to (148.60 ± 3.05) g/L)] in the recombinant protein immunization group than in the infection control group on days 0 to 28 post-immunization. Cytometric bead array detected higher serum interferon-γ [(748.59 ± 17.56) to (3 858.28 ± 1 049.10) fg/mL], tumor necrosis factor-α [(6 687.34 ± 1 016.64) to (12 708.13 ± 1 629.79) fg/mL], interleukin (IL)-6 [(611.05 ± 75.60) to (6 852.68 ± 1 554.00) fg/mL] and IL-17a [(167.68 ± 185.00) to (10 849.27 ± 355.40) fg/mL] and lower IL-10 levels [(247.65 ± 138.00) to (18 787.20 ± 2 830.22) fg/mL] in the recombinant protein immunization group than in the infection control group during the study period. Conclusions Recombinant BmPPIase protein induces up-regulation of interferon-γ, tumor necrosis factor-α and presents a high immunoprotective activity against B. microti infection in mice, which is a potential vaccine candidate protein.
