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Analysis of a Multi-component Multi-stage Malaria Vaccine Candidate--Tackling the Cocktail Challenge.

Boes A, Spiegel H, Voepel N, Edgue G, Beiss V, Kapelski S, Fendel R, Scheuermayer M, Pradel G, Bolscher JM, Behet MC, Dechering KJ, Hermsen CC, Sauerwein RW, Schillberg S, Reimann A, Fischer R - PLoS ONE (2015)

Bottom Line: To investigate the potential of such an approach we combined proteins and domains (11 in total) from the pre-erythrocytic, blood and sexual stages of P. falciparum into a cocktail of four different components recombinantly produced in plants.Using purified rabbit immune IgG we observed strong inhibition in functional in vitro assays addressing the pre-erythrocytic (up to 80%), blood (up to 90%) and sexual parasite stages (100%).While the results underline the feasibility of a multi-stage vaccine cocktail, the analysis of component-specific efficacy indicates significant differences in IC50 requirements for stage-specific antibody concentrations providing valuable insights into this complex scenario and will thereby improve future approaches towards malaria vaccine cocktail development regarding the selection of suitable antigens and the ratios of components, to fine tune overall and stage-specific efficacy.

View Article: PubMed Central - PubMed

Affiliation: Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Aachen, Germany.

ABSTRACT
Combining key antigens from the different stages of the P. falciparum life cycle in the context of a multi-stage-specific cocktail offers a promising approach towards the development of a malaria vaccine ideally capable of preventing initial infection, the clinical manifestation as well as the transmission of the disease. To investigate the potential of such an approach we combined proteins and domains (11 in total) from the pre-erythrocytic, blood and sexual stages of P. falciparum into a cocktail of four different components recombinantly produced in plants. After immunization of rabbits we determined the domain-specific antibody titers as well as component-specific antibody concentrations and correlated them with stage specific in vitro efficacy. Using purified rabbit immune IgG we observed strong inhibition in functional in vitro assays addressing the pre-erythrocytic (up to 80%), blood (up to 90%) and sexual parasite stages (100%). Based on the component-specific antibody concentrations we calculated the IC50 values for the pre-erythrocytic stage (17-25 μg/ml), the blood stage (40-60 μg/ml) and the sexual stage (1.75 μg/ml). While the results underline the feasibility of a multi-stage vaccine cocktail, the analysis of component-specific efficacy indicates significant differences in IC50 requirements for stage-specific antibody concentrations providing valuable insights into this complex scenario and will thereby improve future approaches towards malaria vaccine cocktail development regarding the selection of suitable antigens and the ratios of components, to fine tune overall and stage-specific efficacy.

No MeSH data available.


Related in: MedlinePlus

Correlation of transmission blocking activity and F0-specific antibody concentration.The rabbit IgGs were purified from serum samples collected on day 91 post-immunization with PlasmoMix. To demonstrate the concentration dependency of the transmission blocking activity, the TBA was performed with purified antibodies from each rabbit (R1: black, R2: open and R3: hatched) at total IgG concentrations of 1 mg/ml (circles), 0.1 mg/ml (squares) and 0.01 mg/ml (triangles). Based on the CFCA results, the F0-specific antibody concentration was calculated, plotted and used to determine the IC50 value (the antibody concentration needed to obtain 50% inhibition of transmission). For detailed results of the transmission blocking assay, refer to S2 Table.
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pone.0131456.g006: Correlation of transmission blocking activity and F0-specific antibody concentration.The rabbit IgGs were purified from serum samples collected on day 91 post-immunization with PlasmoMix. To demonstrate the concentration dependency of the transmission blocking activity, the TBA was performed with purified antibodies from each rabbit (R1: black, R2: open and R3: hatched) at total IgG concentrations of 1 mg/ml (circles), 0.1 mg/ml (squares) and 0.01 mg/ml (triangles). Based on the CFCA results, the F0-specific antibody concentration was calculated, plotted and used to determine the IC50 value (the antibody concentration needed to obtain 50% inhibition of transmission). For detailed results of the transmission blocking assay, refer to S2 Table.

Mentions: The SMFA was used to investigate the transmission-blocking efficacy of the sexual stage-specific component F0 (Pfs25 and Pfs230_CO). The observed transmission-blocking activity (reduction in oocyst formation) of 95–100% for the samples from the three animals for all three bleeds (S1 Table) demonstrated the potency of the F0 fusion antigen comprising Pfs25 and Pfs230_CO, agreeing with previous reports based on these antigens [15, 27, 39]. The amounts of F0-specific antibodies measured in the samples taken at day 91 by SPR-based CFCA analysis were correlated with a corresponding dose response TBA, revealing an IC50 value of < 2 μg/ml (Fig 6).


Analysis of a Multi-component Multi-stage Malaria Vaccine Candidate--Tackling the Cocktail Challenge.

Boes A, Spiegel H, Voepel N, Edgue G, Beiss V, Kapelski S, Fendel R, Scheuermayer M, Pradel G, Bolscher JM, Behet MC, Dechering KJ, Hermsen CC, Sauerwein RW, Schillberg S, Reimann A, Fischer R - PLoS ONE (2015)

Correlation of transmission blocking activity and F0-specific antibody concentration.The rabbit IgGs were purified from serum samples collected on day 91 post-immunization with PlasmoMix. To demonstrate the concentration dependency of the transmission blocking activity, the TBA was performed with purified antibodies from each rabbit (R1: black, R2: open and R3: hatched) at total IgG concentrations of 1 mg/ml (circles), 0.1 mg/ml (squares) and 0.01 mg/ml (triangles). Based on the CFCA results, the F0-specific antibody concentration was calculated, plotted and used to determine the IC50 value (the antibody concentration needed to obtain 50% inhibition of transmission). For detailed results of the transmission blocking assay, refer to S2 Table.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4492585&req=5

pone.0131456.g006: Correlation of transmission blocking activity and F0-specific antibody concentration.The rabbit IgGs were purified from serum samples collected on day 91 post-immunization with PlasmoMix. To demonstrate the concentration dependency of the transmission blocking activity, the TBA was performed with purified antibodies from each rabbit (R1: black, R2: open and R3: hatched) at total IgG concentrations of 1 mg/ml (circles), 0.1 mg/ml (squares) and 0.01 mg/ml (triangles). Based on the CFCA results, the F0-specific antibody concentration was calculated, plotted and used to determine the IC50 value (the antibody concentration needed to obtain 50% inhibition of transmission). For detailed results of the transmission blocking assay, refer to S2 Table.
Mentions: The SMFA was used to investigate the transmission-blocking efficacy of the sexual stage-specific component F0 (Pfs25 and Pfs230_CO). The observed transmission-blocking activity (reduction in oocyst formation) of 95–100% for the samples from the three animals for all three bleeds (S1 Table) demonstrated the potency of the F0 fusion antigen comprising Pfs25 and Pfs230_CO, agreeing with previous reports based on these antigens [15, 27, 39]. The amounts of F0-specific antibodies measured in the samples taken at day 91 by SPR-based CFCA analysis were correlated with a corresponding dose response TBA, revealing an IC50 value of < 2 μg/ml (Fig 6).

Bottom Line: To investigate the potential of such an approach we combined proteins and domains (11 in total) from the pre-erythrocytic, blood and sexual stages of P. falciparum into a cocktail of four different components recombinantly produced in plants.Using purified rabbit immune IgG we observed strong inhibition in functional in vitro assays addressing the pre-erythrocytic (up to 80%), blood (up to 90%) and sexual parasite stages (100%).While the results underline the feasibility of a multi-stage vaccine cocktail, the analysis of component-specific efficacy indicates significant differences in IC50 requirements for stage-specific antibody concentrations providing valuable insights into this complex scenario and will thereby improve future approaches towards malaria vaccine cocktail development regarding the selection of suitable antigens and the ratios of components, to fine tune overall and stage-specific efficacy.

View Article: PubMed Central - PubMed

Affiliation: Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Aachen, Germany.

ABSTRACT
Combining key antigens from the different stages of the P. falciparum life cycle in the context of a multi-stage-specific cocktail offers a promising approach towards the development of a malaria vaccine ideally capable of preventing initial infection, the clinical manifestation as well as the transmission of the disease. To investigate the potential of such an approach we combined proteins and domains (11 in total) from the pre-erythrocytic, blood and sexual stages of P. falciparum into a cocktail of four different components recombinantly produced in plants. After immunization of rabbits we determined the domain-specific antibody titers as well as component-specific antibody concentrations and correlated them with stage specific in vitro efficacy. Using purified rabbit immune IgG we observed strong inhibition in functional in vitro assays addressing the pre-erythrocytic (up to 80%), blood (up to 90%) and sexual parasite stages (100%). Based on the component-specific antibody concentrations we calculated the IC50 values for the pre-erythrocytic stage (17-25 μg/ml), the blood stage (40-60 μg/ml) and the sexual stage (1.75 μg/ml). While the results underline the feasibility of a multi-stage vaccine cocktail, the analysis of component-specific efficacy indicates significant differences in IC50 requirements for stage-specific antibody concentrations providing valuable insights into this complex scenario and will thereby improve future approaches towards malaria vaccine cocktail development regarding the selection of suitable antigens and the ratios of components, to fine tune overall and stage-specific efficacy.

No MeSH data available.


Related in: MedlinePlus