1
|
Uwase J, Chu R, Kassegne K, Lei Y, Shen F, Fu H, Sun Y, Xuan Y, Cao J, Cheng Y. Immunogenicity analysis of conserved fragments in Plasmodium ovale species merozoite surface protein 4. Malar J 2020; 19:126. [PMID: 32228600 PMCID: PMC7106901 DOI: 10.1186/s12936-020-03207-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 03/23/2020] [Indexed: 12/28/2022] Open
Abstract
Background There is an urgent need for an effective vaccine to control and eradicate malaria, one of the most serious global infectious diseases. Plasmodium merozoite surface protein 4 (MSP4) has been listed as a blood-stage subunit vaccine candidate for malaria. Infection with Plasmodium ovale species including P. ovale wallikeri and P. ovale curtisi, is also a source of malaria burden in tropical regions where it is sometimes mixed with other Plasmodium species. However, little is known about P. ovale MSP4. Methods The msp4 gene was amplified through polymerase chain reaction using genomic DNA extracted from blood samples of 46 patients infected with P. ovale spp. and amplified products were sequenced. Open reading frames predicted as immunogenic peptides consisting of 119 and 97 amino acids of P. ovale curtisi MSP4 (PocMSP4) and P. ovale wallikeri MSP4 (PowMSP4), respectively, were selected for protein expression. Recombinant proteins (rPoMSP4) were expressed in Escherichia coli, purified, analysed, and immunized in BALB/c mice. The specificity of anti-MSP4-immunoglobulin (Ig) G antibodies was evaluated by Western blot and enzyme-linked immunosorbent assays, and cellular immune responses were analysed via lymphocyte proliferation assays. Results Full peptide sequences of PocMSP4 and PowMSP4 were completely conserved in all clinical isolates, except in the epidermal growth factor-like domain at the carboxyl terminus where only one mutation was observed in one P. o. wallikeri isolate. Further, truncated PoMSP4 segments were successfully expressed and purified as ~ 32 kDa proteins. Importantly, high antibody responses with end-point titres ranging from 1:10,000 to 1:2,560,000 in all immunized mouse groups were observed, with high IgG avidity to PocMSP4 (80.5%) and PowMSP4 (92.3%). Furthermore, rPocMSP4 and rPowMSP4 cross-reacted with anti-PowMSP4-specific or anti-PocMSP4-specific antibodies. Additionally, anti-PoMSP4 IgG antibodies showed broad immuno-specificity in reacting against rPoMSP1 and rPoAMA1. Lastly, PocMSP4- and PowMSP4-immunized mice induced cellular immune responses with PocMSP4 (36%) and PowMSP4 cells (15.8%) during splenocyte proliferation assays. Conclusion Findings from this study suggest conservation in PoMSP4 protein sequences and high immunogenicity was observed in rPoMSP4. Furthermore, induction of immune responses in PocMSP4- and PowMSP4-immunized mice informed that both humoral and cellular immune responses play crucial roles for PoMSP4 in protection.
Collapse
Affiliation(s)
- Juliette Uwase
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China
| | - Ruilin Chu
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China
| | - Kokouvi Kassegne
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China
| | - Yao Lei
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China
| | - Feihu Shen
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China
| | - Haitian Fu
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China
| | - Yifan Sun
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China
| | - Yinghua Xuan
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China
| | - Jun Cao
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China. .,Key Laboratory of National Health and Family Planning Commision on Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasite Diseases, Wuxi, 214064, Jiangsu, People's Republic of China.
| | - Yang Cheng
- Laboratory of Pathogen Infection and Immunity, Department of Public Health and Preventive Medicine, Wuxi School of Medicine, Jiangnan University, Wuxi, 214122, Jiangsu, People's Republic of China.
| |
Collapse
|