Genetic diversity of Plasmodium knowlesi among human and long-tailed macaque populations in Peninsular Malaysia: The utility of microsatellite markers

Abstract Background Understanding the genetic diversity of candidate genes for malaria vaccines such as circumsporozoite protein (csp) may enhance the development of vaccines for treating Plasmodium knowlesi. Hence, the aim of this study is to investigate the genetic diversity of non-repeat regions of csp in P. knowlesi from Malaysian Borneo and Peninsular Malaysia. Methods A total of 46 csp genes were subjected to polymerase chain reaction amplification. The genes were obtained from P. knowlesi isolates collected from different divisions of Sabah, Malaysian Borneo, and Peninsular Malaysia. The targeted gene fragments were cloned into a commercial vector and sequenced, and a phylogenetic tree was constructed while incorporating 168 csp sequences retrieved from the GenBank database. The genetic diversity and natural evolution of the csp sequences were analysed using MEGA6 and DnaSP ver. 5.10.01. A genealogical network of the csp haplotypes was generated using NETWORK ver. 4.6.1.3. Results The phylogenetic analysis revealed indistinguishable clusters of P. knowlesi isolates across different geographic regions, including Malaysian Borneo and Peninsular Malaysia. Nucleotide analysis showed that the csp non-repeat regions of zoonotic P. knowlesi isolates obtained in this study underwent purifying selection with population expansion, which was supported by extensive haplotype sharing observed between humans and macaques. Novel variations were observed in the C-terminal non-repeat region of csp. Conclusions The csp non-repeat regions are relatively conserved and there is no distinct cluster of P. knowlesi isolates from Malaysian Borneo and Peninsular Malaysia. Distinctive variation data obtained in the C-terminal non-repeat region of csp could be beneficial for the design and development of vaccines to treat P. knowlesi.

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Identification, Mapping, and Genetic Diversity of Novel Conserved Cross-Species Epitopes of RhopH2 in Plasmodium knowlesi With Plasmodium vivax

Frontiers in Cellular and Infection Microbiology ◽

10.3389/fcimb.2021.810398 ◽

2022 ◽

Vol 11 ◽

Author(s):

Md Atique Ahmed ◽

Gauspasha Yusuf Deshmukh ◽

Rehan Haider Zaidi ◽

Ahmed Saif ◽

Mohammed Abdulrahman Alshahrani ◽

...

Keyword(s):

Genetic Diversity ◽

Plasmodium Vivax ◽

Protective Immunity ◽

Vaccine Development ◽

Plasmodium Knowlesi ◽

Epitope Prediction ◽

Purifying Selection ◽

Peninsular Malaysia ◽

Health Concern ◽

Clinical Samples

Malaria is a major public health concern, and any tangible intervention during the pre-elimination phase can result in a significant reduction in infection rates. Recent studies have reported that antigens producing cross-protective immunity can play an important role as vaccines and halt malaria transmission in different endemic regions. In this study, we studied the genetic diversity, natural selection, and discovered novel conserved epitopes of a high molecular weight rhoptry protein 2 (RhopH2) in clinical samples of Plasmodium knowlesi and Plasmodium vivax cross-protective domains, which has been proven to produce cross-protective immunity in both species. We found low levels of nucleotide diversity (P. knowlesi; π ~ 0.0093, SNPs = 49 and P. vivax π ~ 0.0014, SNPs = 23) in P. knowlesi (n = 40) and P. vivax (n = 65) samples in the PkRhopH2 cross-protective domain. Strong purifying selection was observed for both species (P. knowlesi; dS - dN = 2.41, p < 0.009, P. vivax; dS - dN = 1.58, p < 0.050). In silico epitope prediction in P. knowlesi identified 10 potential epitopes, of which 7 epitopes were 100% conserved within clinical samples. Of these epitopes, an epitope with 10 amino acids (QNSKHFKKEK) was found to be fully conserved within all P. knowlesi and P. vivax clinical samples and 80%–90% conservation within simian malaria ortholog species, i.e., P. coatneyi and P. cynomolgi. Phylogenetic analysis of the PkRhopH2 cross-protective domain showed geographical clustering, and three subpopulations of P. knowlesi were identified of which two subpopulations originated from Sarawak, Malaysian Borneo, and one comprised only the laboratory lines from Peninsular Malaysia. This study suggests that RhopH2 could be an excellent target for cross-protective vaccine development with potential for outwitting strain as well as species-specific immunity. However, more detailed studies on genetic diversity using more clinical samples from both species as well as the functional role of antibodies specific to the novel conserved epitope identified in this study can be explored for protection against infection.

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Genetic diversity of circumsporozoite protein in Plasmodium knowlesi isolates from Malaysian Borneo and Peninsular Malaysia

10.21203/rs.3.rs-45489/v2 ◽

2020 ◽

Author(s):

Eric Tzyy Jiann Chong ◽

Joveen Wan Fen Neoh ◽

Tiek Ying Lau ◽

Yvonne Ai-Lian Lim ◽

Hwa Chia Chai ◽

...

Keyword(s):

Genetic Diversity ◽

Plasmodium Knowlesi ◽

Polymerase Chain Reaction Amplification ◽

Population Expansion ◽

Purifying Selection ◽

Peninsular Malaysia ◽

Circumsporozoite Protein ◽

Repeat Region ◽

Malaria Vaccines ◽

Malaysian Borneo

Abstract Background: Understanding the genetic diversity of candidate genes for malaria vaccines such as circumsporozoite protein (csp) may enhance the development of vaccines for treating Plasmodium knowlesi. Hence, the aim of this study is to investigate the genetic diversity of non-repeat regions of csp in P. knowlesi from Malaysian Borneo and Peninsular Malaysia. Methods: A total of 46 csp genes were subjected to polymerase chain reaction amplification. The genes were obtained from P. knowlesi isolates collected from different divisions of Sabah, Malaysian Borneo, and Peninsular Malaysia. The targeted gene fragments were cloned into a commercial vector and sequenced, and a phylogenetic tree was constructed while incorporating 168 csp sequences retrieved from the GenBank database. The genetic diversity and natural evolution of the csp sequences were analysed using MEGA6 and DnaSP ver. 5.10.01. A genealogical network of the csp haplotypes was generated using NETWORK ver. 4.6.1.3. Results: The phylogenetic analysis revealed indistinguishable clusters of P. knowlesi isolates across different geographic regions, including Malaysian Borneo and Peninsular Malaysia. Nucleotide analysis showed that the csp non-repeat regions of zoonotic P. knowlesi isolates obtained in this study underwent purifying selection with population expansion, which was supported by extensive haplotype sharing observed between humans and macaques. Novel variations were observed in the C-terminal non-repeat region of csp. Conclusions: The csp non-repeat regions are relatively conserved and there is no distinct cluster of P. knowlesi isolates from Malaysian Borneo and Peninsular Malaysia. Distinctive variation data obtained in the C-terminal non-repeat region of csp could be beneficial for the design and development of vaccines to treat P. knowlesi.

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Genetic diversity, haplotypes and allele groups of Duffy binding protein (PkDBPαII) of Plasmodium knowlesi clinical isolates from Peninsular Malaysia

Parasites & Vectors ◽

10.1186/1756-3305-7-161 ◽

2014 ◽

Vol 7 (1) ◽

pp. 161 ◽

Cited By ~ 20

Author(s):

Mun-Yik Fong ◽

Yee-Ling Lau ◽

Phooi-Yee Chang ◽

Claudia Anthony

Keyword(s):

Genetic Diversity ◽

Plasmodium Knowlesi ◽

Binding Protein ◽

Peninsular Malaysia ◽

Clinical Isolates ◽

Duffy Binding Protein

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Genetic diversity of the full length apical membrane antigen-1 of Plasmodium knowlesi clinical isolates from Peninsular Malaysia

Tropical Biomedicine ◽

10.47665/tb.38.2.052 ◽

2021 ◽

Vol 38 (2) ◽

pp. 159-164

Author(s):

Ng Y.L.

Keyword(s):

Genetic Diversity ◽

Apical Membrane ◽

Plasmodium Knowlesi ◽

Peninsular Malaysia ◽

Full Length ◽

Clinical Isolates ◽

Apical Membrane Antigen 1 ◽

Apical Membrane Antigen

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Genetic diversity of circumsporozoite protein in Plasmodium knowlesi isolates from Malaysian Borneo and Peninsular Malaysia

10.21203/rs.3.rs-45489/v1 ◽

2020 ◽

Author(s):

Eric Tzyy Jiann Chong ◽

Joveen Wan Fen Neoh ◽

Tiek Ying Lau ◽

Yvonne Ai-Lian Lim ◽

Hwa Chia Chai ◽

...

Keyword(s):

Genetic Diversity ◽

Plasmodium Knowlesi ◽

Polymerase Chain Reaction Amplification ◽

Population Expansion ◽

Purifying Selection ◽

Peninsular Malaysia ◽

Circumsporozoite Protein ◽

Malaria Vaccines ◽

Reaction Amplification ◽

Malaysian Borneo

Abstract Background Understanding the genetic diversity of candidate genes for malaria vaccines such as circumsporozoite protein (csp) may enhance the development of vaccines for treating Plasmodium knowlesi. Hence, the aim of this study is to investigate the genetic diversity of non-repeat regions of csp in P. knowlesi from Malaysian Borneo and Peninsular Malaysia. Methods A total of 46 csp genes were subjected to polymerase chain reaction amplification. The genes were obtained from P. knowlesi isolates collected from different divisions of Sabah, Malaysian Borneo, and Peninsular Malaysia. The targeted gene fragments were cloned into a commercial vector and sequenced, and a phylogenetic tree was constructed while incorporating 168 csp sequences retrieved from the GenBank database. The genetic diversity and natural evolution of the csp sequences were analysed using MEGA6 and DnaSP ver. 5.10.01. A genealogical network of the csp haplotypes was generated using NETWORK ver. 4.6.1.3. Results The phylogenetic analysis revealed indistinguishable clusters of P. knowlesi isolates across different geographic regions, including Malaysian Borneo and Peninsular Malaysia. Nucleotide analysis showed that the csp non-repeat regions of zoonotic P. knowlesi isolates obtained in this study underwent purifying selection with population expansion, which was supported by extensive haplotype sharing observed between humans and macaques. Conclusions The csp non-repeat regions are relatively conserved and cannot be used to distinguish P. knowlesi isolates between Malaysian Borneo and Peninsular Malaysia. Novel variations were observed in the C-terminal non-repeat region of csp. The data obtained could be beneficial for the design and development of vaccines to treat P. knowlesi.

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