Evaluation of two Plasmodium vivax sexual-stage antigens as transmission-blocking vaccine candidates

2021 ◽  
Author(s):  
Yongzhe Zhang ◽  
Fei Liu ◽  
Yan Zhao ◽  
Fan Yang ◽  
Jie Bai ◽  
...  
Keyword(s):  
Amino Acids ◽  
Plasmodium Vivax ◽  
Recombinant Proteins ◽  
Expression System ◽  
Transmission Blocking ◽  
Yeast Expression System ◽  
Membrane Feeding ◽  
Reducing Activity ◽  
Membrane Feeding Assay ◽  
Transmission Blocking Vaccines

Abstract Background: Plasmodium vivax transmission-blocking vaccines (TBVs) have received high attention. PVX_098655 (PvPH) and PVX_101120 (PvSOP26) were predicted to be potential TBV antigens based on the studies of their orthologs in Plasmodium berghei. Methods: Fragments of PvPH (amino acids 22–304) and PvSOP26 (amino acids 30–272) were expressed in the yeast expression system. The recombinant proteins were used to immunize mice to obtain the antisera. The transmission-reducing activities of these antisera were evaluated using the standard membrane feeding assay (SMFA) using Anopheles dirus mosquitoes and P. vivax clinical isolates. Results: The recombinant proteins PvPH and PvSOP26 induced robust antibody responses in mice. With SMFA, the anti-PvSOP26 sera significantly reduced oocyst densities by 92.0% and 84.1% in two parasite isolates, while the anti-PvPH sera did not show evident transmission-reducing activity. Both PvPH and PvSOP26 showed limited gene polymorphisms in the clinical P. vivax isolates. Conclusion: PvSOP26 could be a promising TBV candidate for P. vivax.

scholarly journals Evaluation of two Plasmodium vivax sexual stage antigens as transmission-blocking vaccine candidates

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Yongzhe Zhang ◽  
Fei Liu ◽  
Yan Zhao ◽  
Fan Yang ◽  
Jie Bai ◽  
...  
Keyword(s):  
Amino Acids ◽  
Plasmodium Vivax ◽  
Recombinant Proteins ◽  
Expression System ◽  
Anopheles Dirus ◽  
Transmission Blocking ◽  
Yeast Expression System ◽  
Membrane Feeding ◽  
Reducing Activity ◽  
Membrane Feeding Assay

Abstract Background Plasmodium vivax transmission-blocking vaccines (TBVs) are receiving increasing attention. Based on excellent transmission-blocking activities of the PbPH (PBANKA_0417200) and PbSOP26 (PBANKA_1457700) antigens in Plasmodium berghei, their orthologs in P. vivax, PVX_098655 (PvPH) and PVX_101120 (PvSOP26), were selected for the evaluation of their potential as TBVs. Methods Fragments of PvPH (amino acids 22–304) and PvSOP26 (amino acids 30–272) were expressed in the yeast expression system. The recombinant proteins were used to immunize mice to obtain antisera. The transmission-reducing activities of these antisera were evaluated using the direct membrane feeding assay (DMFA) using Anopheles dirus mosquitoes and P. vivax clinical isolates. Results The recombinant proteins PvPH and PvSOP26 induced robust antibody responses in mice. The DMFA showed that the anti-PvSOP26 sera significantly reduced oocyst densities by 92.0 and 84.1% in two parasite isolates, respectively, whereas the anti-PvPH sera did not show evident transmission-reducing activity. The variation in the DMFA results was unlikely due to the genetic polymorphisms of the two genes since their respective sequences were identical in the clinical P. vivax isolates. Conclusion PvSOP26 could be a promising TBV candidate for P. vivax, which warrants further evaluation. Graphical Abstract

scholarly journals Evaluation and modeling of direct membrane-feeding assay with Plasmodium vivax to support development of transmission blocking vaccines

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Kazutoyo Miura ◽  
Bruce J. Swihart ◽  
Michael P. Fay ◽  
Chalermpon Kumpitak ◽  
Kirakorn Kiattibutr ◽  
...  
Keyword(s):  
Plasmodium Vivax ◽  
Feeding Assay ◽  
Transmission Blocking ◽  
Membrane Feeding ◽  
Membrane Feeding Assay ◽  
Transmission Blocking Vaccines

scholarly journals Anti-Pfs25 Human Plasma Reduces Transmission of Plasmodium falciparum Isolates That Have Diverse Genetic Backgrounds

2013 ◽  
Vol 81 (6) ◽  
pp. 1984-1989 ◽  
Author(s):  
Dari F. Da ◽  
Saurabh Dixit ◽  
Jetsumon Sattabonkot ◽  
Jianbing Mu ◽  
Luc Abate ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Burkina Faso ◽  
Phase 1 ◽  
Transmission Blocking ◽  
Content Type ◽  
Phase 1 Trial ◽  
Membrane Feeding ◽  
Geographical Regions ◽  
Reducing Activity ◽  
Membrane Feeding Assay

ABSTRACTPfs25 is a leading candidate for a malaria transmission-blocking vaccine whose potential has been demonstrated in a phase 1 trial with recombinant Pfs25 formulated with Montanide ISA51. Because of limited sequence polymorphism, the anti-Pfs25 antibodies induced by this vaccine are likely to have transmission-blocking or -reducing activity against most, if not all, field isolates. To test this hypothesis, we evaluated transmission-blocking activities by membrane feeding assay of anti-Pfs25 plasma from the Pfs25/ISA51 phase 1 trial againstPlasmodium falciparumparasites from patients in two different geographical regions of the world, Thailand and Burkina Faso. In parallel, parasite isolates from these patients were sequenced for the Pfs25 gene and genotyped for seven microsatellites. The results indicate that despite different genetic backgrounds among parasite isolates, the Pfs25 sequences are highly conserved, with a single nonsynonymous nucleotide polymorphism detected in 1 of 41 patients in Thailand and Burkina Faso. The anti-Pfs25 immune plasma had significantly higher transmission-reducing activity against parasite isolates from the two geographical regions than the nonimmune controls (P< 0.0001).

scholarly journals Functional Comparison of Plasmodium falciparum Transmission-Blocking Vaccine Candidates by the Standard Membrane-Feeding Assay

2013 ◽  
Vol 81 (12) ◽  
pp. 4377-4382 ◽  
Author(s):  
Kazutoyo Miura ◽  
Eizo Takashima ◽  
Bingbing Deng ◽  
Gregory Tullo ◽  
Ababacar Diouf ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Recombinant Proteins ◽  
The Other ◽  
Enzyme Linked Immunosorbent Assay ◽  
Dependent Manner ◽  
Feeding Assay ◽  
Transmission Blocking ◽  
Content Type ◽  
Membrane Feeding ◽  
Membrane Feeding Assay

ABSTRACTRecently, there has been a renewed interest in the development of transmission-blocking vaccines (TBV) againstPlasmodium falciparummalaria. While several candidate TBVs have been reported, studies directly comparing them in functional assays are limited. To this end, recombinant proteins of TBV candidates Pfs25, Pfs230, and PfHAP2 were expressed in the wheat germ cell-free expression system. Outbred CD-1 mice were immunized twice with the antigens. Two weeks after the second immunization, IgG levels were measured by enzyme-linked immunosorbent assay (ELISA), and IgG functionality was assessed by the standard membrane-feeding assay (SMFA) using culturedP. falciparumNF54 gametocytes andAnopheles stephensimosquitoes. All three recombinant proteins elicited similar levels of antigen-specific IgG judged by ELISA. When IgGs purified from pools of immune serum were tested at 0.75 mg/ml in the SMFA, all three IgGs showed 97 to 100% inhibition in oocyst intensity compared to control IgG. In two additional independent SMFA evaluations, anti-Pfs25, anti-Pfs230, and anti-PfHAP2 IgGs inhibited oocyst intensity in a dose-dependent manner. When all three data sets were analyzed, anti-Pfs25 antibody showed significantly higher inhibition than the other two antibodies (P< 0.001 for both), while there was no significant difference between the other two (P= 0.15). A proportion of plasma samples collected from adults living in an area of malaria endemicity in Mali recognized Pfs230 and PfHAP2. This is the first study showing that the HAP2 protein ofP. falciparumcan induce transmission-blocking antibody. The current study supports the possibility of using this system for a comparative study with multiple TBV candidates.

Evaluation of the standard membrane feeding assay (SMFA) for the determination of malaria transmission-reducing activity using empirical data

Parasitology ◽  
2004 ◽  
Vol 130 (1) ◽  
pp. 13-22 ◽  
Author(s):  
M. VAN DER KOLK ◽  
S. J. DE VLAS ◽  
A. SAUL ◽  
M. VAN DE VEGTE-BOLMER ◽  
W. M. ELING ◽  
...  
Keyword(s):  
Repeated Measurements ◽  
Host Responses ◽  
Feeding Assay ◽  
Human Red Blood Cells ◽  
Membrane Feeding ◽  
Reducing Activity ◽  
And Control ◽  
Membrane Feeding Assay ◽  
Transmission Blocking Vaccines

Host responses to the transmittable stages of the malaria parasite may reduce transmission effectively. Transmission-reducing activity (TRA) of human serum can be determined as a percentage, using the Standard Membrane Feeding Assay (SMFA). This laboratory assay was evaluated using the results of 121 experiments with malaria-endemic sera among which many repeated measurements were obtained. The assay consists of the feeding ofAnopheles stephensimosquitoes with culturedPlasmodium falciparumgametocytes, mixed with human red blood cells, and control and experimental sera. The TRA of individual sera was determined by the comparison of oocyst densities between these sera. Bootstrap data on oocyst densities in individual mosquitoes in control feeds were used to construct confidence limits for TRA percentages of serum feeds. Low (<20%) and high TRA (>90%) values for individual sera were usually reproduced in a second experiment, whereas this was more difficult for values between 20% and 90%. The observed variability of TRA values is explained in part by the variability in oocyst density per mosquito. Oocyst densities in control feeds varied more between experiments than within experiments and showed a slight decline over the 3 years of experiments. Reproducibility of TRA of field sera was low (20%) between experiments, but much higher (61%) within experiments. A minimum of 35 oocysts per mosquito in control feeds gave optimal reproducibility (44%) between experiments. We recommend that (1) sera are compared within an experiment, or (2) assays are only analysed where controls have at least 35 oocysts per mosquito. The SMFA is under the recommended conditions appropriate for the study of factors that may influence TRA, e.g. transmission blocking vaccines.

scholarly journals Optimization of a Membrane Feeding Assay for Plasmodium vivax Infection in Anopheles albimanus

2016 ◽  
Vol 10 (6) ◽  
pp. e0004807 ◽  
Author(s):  
Andrés F. Vallejo ◽  
Kelly Rubiano ◽  
Andres Amado ◽  
Amy R. Krystosik ◽  
Sócrates Herrera ◽  
...  
Keyword(s):  
Plasmodium Vivax ◽  
Vivax Infection ◽  
Anopheles Albimanus ◽  
Feeding Assay ◽  
Membrane Feeding ◽  
Membrane Feeding Assay

scholarly journals Crystallization of recombinant hemoglobins with basic amino acid substitutions (Lys and Arg) at the beta 6 position

Blood ◽  
1994 ◽  
Vol 84 (4) ◽  
pp. 1309-1313
Author(s):  
K Adachi ◽  
CH Lai ◽  
P Konitzer ◽  
M Donahee ◽  
A Campbell ◽  
...  
Keyword(s):  
Amino Acids ◽  
Expression System ◽  
Basic Amino Acid ◽  
Cellulose Acetate Electrophoresis ◽  
Yeast Expression System ◽  
Basic Amino Acids ◽  
Beta 2 ◽  
Hb Concentration ◽  
Hb C

We have produced recombinant hemoglobins (rHbs) alpha 2 beta 2(6Glu-- >Lys) (rHb beta E6K) and alpha 2 beta 2(6Glu-->Arg) (rHb beta E6R) using a yeast expression system coupled with a polymerase chain reaction (PCR)-based mutagenesis strategy for studies focused on defining determinants that facilitate crystallization of Hb C (alpha 2 beta 2(6Lys)). rHb beta E6K had the same electrophoretic mobility as native human Hb C, whereas rHb beta E6R migrated slightly slower than Hb C on cellulose acetate electrophoresis. The carbonmonoxy (CO) forms of rHb beta E6K and rHb beta E6R formed tetrahedral crystals in vitro in 2.3 mol/L phosphate buffer just like native Hb C. The Hb concentration required for crystallization of CO-rHb beta E6R was lower than that of CO-rHb beta E6K, suggesting that stronger basic amino acids at the beta 6 position accelerate crystallization of Hb. However, the size of rHb beta E6R crystals was smaller than that of rHb beta E6K. Crystallization of native Hb C and both rHbs was inhibited by Hb F. These results suggest that alpha 2 beta gamma-heterohybrids that have basic amino acids at the beta 6 position behave similarly and are unable to crystallize like Hb C.

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