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

2020 ◽  
Author(s):  
Uwase Juliette ◽  
Ruilin Chu ◽  
Kokouvi Kassegne ◽  
Yao Lei ◽  
Feihu Shen ◽  
...  
Keyword(s):  
Immune Responses ◽  
Plasmodium Species ◽  
Surface Protein ◽  
Merozoite Surface Protein ◽  
Effective Vaccine ◽  
Plasmodium Ovale ◽  
Tropical Regions ◽  
Cellular Immune Responses ◽  
Cellular Immune ◽  
Proliferation Assays

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. Plasmodium ovale species (spp.) infection 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 spp. 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, analyzed, and immunized in BALB/c mice. The specificity of anti-MSP4-immunoglubulin (Ig) G antibodies was evaluated by Western blot and enzyme-linked immunosorbent assays, and cellular immune responses were analyzed 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. ovale wallikeri isolate. Furthermore, we successfully expressed the truncated pocmsp4 and powmsp4 and purified as ~32 kDa proteins. Our results showed that PocMSP4 and PowMSP4 induced high antibody responses with end-point titers ranging from 1:10,000 to 1:2,560,000 in all immunized mouse groups and 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%) as observed through splenocyte proliferation assays. Conclusion: Our study suggested conservation in PoMSP4 protein sequences and high immunogenicity was observed in rPoMSP4. Furthermore, PocMSP4- and PowMSP4-immunized mice induced cellular immune responses, suggesting that both humoral and cellular immune responses play crucial roles in the protection against any antigen.

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

2020 ◽  
Author(s):  
Juliette Uwase ◽  
Ruilin Chu ◽  
Kokouvi Kassegne ◽  
Yao Lei ◽  
Feihu Shen ◽  
...  
Keyword(s):  
Immune Responses ◽  
Plasmodium Species ◽  
Surface Protein ◽  
Merozoite Surface Protein ◽  
Effective Vaccine ◽  
Plasmodium Ovale ◽  
Tropical Regions ◽  
Cellular Immune Responses ◽  
Cellular Immune ◽  
Proliferation Assays

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. Plasmodium ovale species (spp.) infection 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 spp. 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, analyzed, and immunized in BALB/c mice. The specificity of anti-MSP4-immunoglubulin (Ig) G antibodies was evaluated by Western blot and enzyme-linked immunosorbent assays, and cellular immune responses were analyzed 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. ovale wallikeri isolate. Furthermore, we successfully expressed the truncated pocmsp4 and powmsp4 and purified as ~32 kDa proteins. Our results showed that PocMSP4 and PowMSP4 induced high antibody responses with end-point titers ranging from 1:10,000 to 1:2,560,000 in all immunized mouse groups and 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%) as observed through splenocyte proliferation assays. Conclusion : Our study suggested conservation in PoMSP4 protein sequences and high immunogenicity was observed in rPoMSP4. Furthermore, PocMSP4- and PowMSP4-immunized mice induced cellular immune responses, suggesting that both humoral and cellular immune responses play crucial roles in the protection against any antigen.

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

2020 ◽  
Author(s):  
Uwase Juliette ◽  
Ruilin Chu ◽  
Kokouvi Kassegne ◽  
Yao Lei ◽  
Feihu Shen ◽  
...  
Keyword(s):  
Immune Responses ◽  
Surface Protein ◽  
Merozoite Surface Protein ◽  
Effective Vaccine ◽  
Plasmodium Ovale ◽  
Tropical Regions ◽  
Malaria Burden ◽  
Cellular Immune Responses ◽  
Cellular Immune ◽  
Proliferation Assays

Abstract Background: An effective vaccine to control and eradicate malaria, one of the most serious global infectious diseases, is an urgent need. Plasmodium merozoite surface protein 4 (MSP4) has been listed as a blood-stage subunit vaccine candidate for malaria. Plasmodium ovale infection 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 and then 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, analyzed, and immunized in BALB/c mice. The specificity of anti-MSP4-immunoglubulin (Ig) G antibodies was evaluated by Western blot and enzyme-linked immunosorbent assays, and cellular immune responses were analyzed 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. ovale wallikeri isolate. Furthermore, we successfully expressed the truncated pocmsp4 and powmsp4 and purified as ~32 kDa proteins. Our results showed that PocMSP4 and PowMSP4 induced high antibody responses with end-point titers ranging from 1:2,560,000 to 1:10,000 in all immunized mouse groups and 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%) as observed through splenocyte proliferation assays. Conclusion: Our study suggested conservation in PoMSP4 protein sequences with high immunogenicity. Furthermore, PocMSP4- and PowMSP4-immunized mice induced cellular immune responses, suggesting that both humoral and cellular immune responses play crucial roles in the protection against any antigen.

scholarly journals Genetic diversity and immunogenicity of the merozoite surface protein 1 C-terminal 19-kDa fragment of Plasmodium ovale imported from Africa into China

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Qinwen Xu ◽  
Sihong Liu ◽  
Kokouvi Kassegne ◽  
Bo Yang ◽  
Jiachen Lu ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Immune Responses ◽  
Expression System ◽  
Surface Protein ◽  
Merozoite Surface Protein ◽  
Enzyme Linked Immunosorbent Assay ◽  
High Avidity ◽  
Plasmodium Ovale ◽  
Merozoite Surface Protein 1 ◽  
Proliferation Assays

Abstract Background Merozoite surface protein 1 (MSP1) plays an essential role in erythrocyte invasion by malaria parasites. The C-terminal 19-kDa region of MSP1 has long been considered one of the major candidate antigens for a malaria blood-stage vaccine against Plasmodium falciparum. However, there is limited information on the C-terminal 19-kDa region of Plasmodium ovale MSP1 (PoMSP119). This study aims to analyze the genetic diversity and immunogenicity of PoMSP119. Methods A total of 37 clinical Plasmodium ovale isolates including Plasmodium ovale curtisi and Plasmodium ovale wallikeri imported from Africa into China and collected during the period 2012–2016 were used. Genomic DNA was used to amplify P. ovale curtisi (poc) msp119 (pocmsp119) and P. ovale wallikeri (pow) msp119 (powmsp119) genes by polymerase chain reaction. The genetic diversity of pomsp119 was analyzed using the GeneDoc version 6 programs. Recombinant PoMSP119 (rPoMSP119)-glutathione S-transferase (GST) proteins were expressed in an Escherichia coli expression system and analyzed by western blot. Immune responses in BALB/c mice immunized with rPoMSP119-GST were determined using enzyme-linked immunosorbent assay. In addition, antigen-specific T cell responses were assessed by lymphocyte proliferation assays. A total of 49 serum samples from healthy individuals and individuals infected with P. ovale were used for the evaluation of natural immune responses by using protein microarrays. Results Sequences of pomsp119 were found to be thoroughly conserved in all the clinical isolates. rPoMSP119 proteins were efficiently expressed and purified as ~ 37-kDa proteins. High antibody responses in mice immunized with rPoMSP119-GST were observed. rPoMSP119-GST induced high avidity indexes, with an average of 92.57% and 85.32% for rPocMSP119 and rPowMSP119, respectively. Cross-reactivity between rPocMSP119 and rPowMSP119 was observed. Cellular immune responses to rPocMSP119 (69.51%) and rPowMSP119 (52.17%) induced in rPocMSP119- and rPowMSP119-immunized mice were found in the splenocyte proliferation assays. The sensitivity and specificity of rPoMSP119-GST proteins for the detection of natural immune responses in patients infected with P. ovale were 89.96% and 75%, respectively. Conclusions This study revealed highly conserved gene sequences of pomsp119. In addition, naturally acquired humoral immune responses against rPoMSP1 were observed in P. ovale infections, and high immunogenicity of rPoMSP119 in mice was also identified. These instructive findings should encourage further testing of PoMSP119 for rational vaccine design. Graphical abstract

scholarly journals Naturally acquired humoral and cellular immune responses to Plasmodium vivax merozoite surface protein 9 in Northwestern Amazon individuals

Vaccine ◽  
2008 ◽  
Vol 26 (51) ◽  
pp. 6645-6654 ◽  
Author(s):  
J.C. Lima-Junior ◽  
T.M. Tran ◽  
E.V.S. Meyer ◽  
B. Singh ◽  
S.G. De-Simone ◽  
...  
Keyword(s):  
Immune Responses ◽  
Plasmodium Vivax ◽  
Surface Protein ◽  
Merozoite Surface Protein ◽  
Cellular Immune Responses ◽  
Cellular Immune

scholarly journals Genetic diversity and immunogenicity of the merozoite surface protein 1 C-terminal 19-kDa fragment (MSP119) of Plasmodium ovale imported from Africa to China

2021 ◽  
Author(s):  
Qinwen Xu ◽  
Sihong Liu ◽  
Kokouvi Kassegne ◽  
Bo Yang ◽  
Jiachen Lu ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Immune Responses ◽  
Expression System ◽  
Surface Protein ◽  
Merozoite Surface Protein ◽  
High Avidity ◽  
Natural Immunity ◽  
Plasmodium Ovale ◽  
Merozoite Surface Protein 1 ◽  
Proliferation Assays

Abstract Background Merozoite surface protein 1 (MSP1) plays an essential role in erythrocyte invasion by malaria parasites. The C-terminal 19-kDa of MSP1 has long been considered as one of the major candidate antigens for malaria blood-stage vaccine in Plasmodium falciparum. However, there are limited information on the C-terminal 19-kDa region of Plasmodium ovale merozoite surface protein 1 (PoMSP119). This study, therefore, aims to analyse genetic diversity and immunogenicity of PoMSP119. Methods A total of 37 clinical P. ovale isolates including P. ovale curtisi (Poc) and P. ovale wallikeri (Pow) imported from Africa to China and collected between 2012 and 2016 were used. Genomic DNA were used to amplify pocmsp119 and powmsp119 genes by polymerase chain reaction (PCR). Genetic diversity of pomsp119 was analyzed using the MegAlign and GeneDoc v.6 programs. Recombinant PoMSP119-GST proteins were expressed in an Escherichia coli expression system and analyzed by Western blot. Immune responses in BALB/c mice immunized with rPoMSP119-GST were determined using enzyme-linked immunosorbent assays (ELISA). In addition, antigen-specific T-cell responses were performed by lymphocyte proliferation assays. A total of 49 serum samples from P. ovale infections and healthy people were used to evaluate natural immune responses through protein microarray assays. Results Sequences of pomsp119 were found thoroughly conserved in all clinical isolates. Recombinant PoMSP119 proteins were efficiently expressed and purified as ~ 37 kDa proteins. High antibody responses in immunized mice with rPoMSP119-GST were observed. The rPoMSP119-GST induced high avidity indexes with an average of 92.57% and 85.32% for Poc and Pow, respectively. Cross-reactivity between rPocMSP119 and rPowMSP119 was observed. Cellular immune responses to rPocMSP119 (69.51%) and rPowMSP119 (52.17%) induced in rPocMSP119- and rPowMSP119-immunized mice were found during splenocyte proliferation assays. The sensitivity and specificity of rPoMSP119-GST proteins for natural immune responses detection in patients infected with P. ovale were 89.96% and 75%, respectively. Conclusions This study revealed high conservation in sequences of pomsp119 and high immunogenicity of rPoMSP119. The rPoMSP119 proteins detected humoral immune responses in patients with P. ovale infection. Such informative results advance our understanding of natural immunity to P. ovale infection and contribute to the knowledge base for the development of a PoMSP119-based vaccine.

scholarly journals A Combined Adjuvant TF–Al Consisting of TFPR1 and Aluminum Hydroxide Augments Strong Humoral and Cellular Immune Responses in Both C57BL/6 and BALB/c Mice

Vaccines ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 1408
Author(s):  
Qiao Li ◽  
Zhihua Liu ◽  
Yi Liu ◽  
Chen Liang ◽  
Jiayi Shu ◽  
...  
Keyword(s):  
Immune Responses ◽  
Vaccine Development ◽  
Inbred Mouse ◽  
Effective Vaccine ◽  
Mouse Strains ◽  
Cellular Immune Responses ◽  
Recombinant Hbsag ◽  
Cellular Immune

TFPR1 is a novel adjuvant for protein and peptide antigens, which has been demonstrated in BALB/c mice in our previous studies; however, its adjuvanticity in mice with different genetic backgrounds remains unknown, and its adjuvanticity needs to be improved to fit the requirements for various vaccines. In this study, we first compared the adjuvanticity of TFPR1 in two commonly used inbred mouse strains, BALB/c and C57BL/6 mice, in vitro and in vivo, and demonstrated that TFPR1 activated TLR2 to exert its immune activity in vivo. Next, to prove the feasibility of TFPR1 acting as a major component of combined adjuvants, we prepared a combined adjuvant, TF–Al, by formulating TFPR1 and alum at a certain ratio and compared its adjuvanticity with that of TFPR1 and alum alone using OVA and recombinant HBsAg as model antigens in both BALB/c and C57BL/6 mice. Results showed that TFPR1 acts as an effective vaccine adjuvant in both BALB/c mice and C57BL/6 mice, and further demonstrated the role of TLR2 in the adjuvanticity of TFPR1 in vivo. In addition, we obtained a novel combined adjuvant, TF–Al, based on TFPR1, which can augment antibody and cellular immune responses in mice with different genetic backgrounds, suggesting its promise for vaccine development in the future.

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