Immunogenicity analysis of conserved fragments in Plasmodium ovale species merozoite surface protein 4

作者：Uwase Juliette, Ruilin Chu, Kokouvi Kassegne, Yao Lei, Feihu Shen, Haitian Fu, Yifan Sun, Ying-Hua Xuan, Jun Cao, Yang Cheng · 发表于：Malaria Journal · 年份：2020 · DOI：10.1186/s12936-020-03207-7 · 被引用次数：11 · 研究领域：Malaria Research and Control、Invertebrate Immune Response Mechanisms、vaccines and immunoinformatics approaches

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. walli...