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Comparative analysis of IgG responses to Plasmodium falciparum MSP1p19 and PF13-DBL1α1 using ELISA and a magnetic bead-based duplex assay (MAGPIX®-Luminex) in a Senegalese meso-endemic community.

Perraut R, Richard V, Varela ML, Trape JF, Guillotte M, Tall A, Toure A, Sokhna C, Vigan-Womas I, Mercereau-Puijalon O - Malar. J. (2014)

Bottom Line: Numerous Plasmodium falciparum antigens elicit humoral responses in humans living in endemic areas.Archived plasma samples collected before the rainy season from 217 villagers living in Ndiop, a Senegalese meso-endemic setting, were studied.This may reflect incomplete overlap of the epitopes presented in the two formats.

View Article: PubMed Central - PubMed

Affiliation: Institut Pasteur de Dakar, Unité d'Immunologie, Dakar, Sénégal. perraut@pasteur.sn.

ABSTRACT

Background: Numerous Plasmodium falciparum antigens elicit humoral responses in humans living in endemic areas. Use of multiplex assays is a convenient approach to monitor the antibody response against multiple antigens, but to integrate multiplex assay-derived data with datasets, generated previously using ELISA, comparative studies are needed. This work compares antibody responses to two P. falciparum antigens monitored using both technologies.

Methods: The IgG response against the merozoite surface protein-1 PfMSP1p19 and the PF13-DBL1α1 domain of the P. falciparum Erythrocyte Membrane Protein1, expressed by the rosette-forming parasite 3D7/PF13 (PF13), was investigated using ELISA and a MAGPIX®-Luminex duplex assay. Archived plasma samples collected before the rainy season from 217 villagers living in Ndiop, a Senegalese meso-endemic setting, were studied. ROC analysis was used to define the optimal antibody measure readout. Association of antibody levels with protection against clinical malaria was analysed using Poisson regression in a retrospective study from active case detection records performed during the 5.5-month transmission season that followed blood sampling.

Results: There was a strong positive correlation (P<10(-3)) between ELISA and MAGPIX®-Luminex-MFI (median fluorescence intensity) values for antibody to PfMSP1p19 (rho=0.78) and PF13-DBL1α1 (rho=0.89), with a similar degree of concordance in all age groups. Antibody levels to both antigens were high but displayed a different age-associated pattern. Independent age-adjusted Poisson regression analysis showed a significant association with protection only for IgG responses to MSP1p19 (P<0.01 RR=0.71 [0.53-0.93]) measured by ELISA.

Conclusion: The individual ELISA and duplex-MAGPIX assays provide a concordant evaluation of age-associated antibody responses to MSP1p19 and PF13-DBL1α1, irrespective of the formulation of antibody levels (values, ratios or ROC-adjusted figures) but do diverge with regard to the association of antibody levels with clinical protection in age-adjusted models. This may reflect incomplete overlap of the epitopes presented in the two formats. Further development for multiplex assessment of antibody responses to a larger panel of antigens with the robust and cost effective MAGPIX®-Luminex technology is warranted.

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Correlation between the results from ELISA and duplex MBA using the Spearman’s rank correlation test and ROC curves calculation output. ELISA OD (Y axis) vs MFI (X axis) values are plotted for IgG responses against PF13 (a) and MSP1p19 (b). The regression line indicates a significant correlation (P <10-3) of antibody responses measured by two methods for PF13 (rho = 0.89) and for MSP1p19 (rho = 0.78). The ROC curves plotting specificity vs sensitivity of the two methods, used to calculate the best cut-off point, are shown for PF13 (c) and MSP1p19 (d).
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Fig1: Correlation between the results from ELISA and duplex MBA using the Spearman’s rank correlation test and ROC curves calculation output. ELISA OD (Y axis) vs MFI (X axis) values are plotted for IgG responses against PF13 (a) and MSP1p19 (b). The regression line indicates a significant correlation (P <10-3) of antibody responses measured by two methods for PF13 (rho = 0.89) and for MSP1p19 (rho = 0.78). The ROC curves plotting specificity vs sensitivity of the two methods, used to calculate the best cut-off point, are shown for PF13 (c) and MSP1p19 (d).

Mentions: As illustrated in Figure 1, there was a significant (P <10-3) positive correlation between MFI and OD values for antibody responses to PF13 (Figure 1a, rho = 0.89) and to MSP1p19 (Figure 1b, rho = 0.78) monitored by the two methodologies. When including only positive responders (ie, individuals with OD-ratio >2), the correlation remained significantly positive (P < 10-3), rho = 0.80 and 0.65 for PF13 and MSP1p19, respectively. When stratifying by age group, antibody levels showed a similar degree of concordance of the two techniques in all age groups (<5, 5–10, 10–15, 15–29, and ≥30 years) for PF13 (rho = 0.89, 0.90, 0.83, 0.89, 0.85, respectively) and MSP1p19 (rho = 0.97, 0.68, 0.82, 0.80, 0.72, respectively).Figure 1


Comparative analysis of IgG responses to Plasmodium falciparum MSP1p19 and PF13-DBL1α1 using ELISA and a magnetic bead-based duplex assay (MAGPIX®-Luminex) in a Senegalese meso-endemic community.

Perraut R, Richard V, Varela ML, Trape JF, Guillotte M, Tall A, Toure A, Sokhna C, Vigan-Womas I, Mercereau-Puijalon O - Malar. J. (2014)

Correlation between the results from ELISA and duplex MBA using the Spearman’s rank correlation test and ROC curves calculation output. ELISA OD (Y axis) vs MFI (X axis) values are plotted for IgG responses against PF13 (a) and MSP1p19 (b). The regression line indicates a significant correlation (P <10-3) of antibody responses measured by two methods for PF13 (rho = 0.89) and for MSP1p19 (rho = 0.78). The ROC curves plotting specificity vs sensitivity of the two methods, used to calculate the best cut-off point, are shown for PF13 (c) and MSP1p19 (d).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4221706&req=5

Fig1: Correlation between the results from ELISA and duplex MBA using the Spearman’s rank correlation test and ROC curves calculation output. ELISA OD (Y axis) vs MFI (X axis) values are plotted for IgG responses against PF13 (a) and MSP1p19 (b). The regression line indicates a significant correlation (P <10-3) of antibody responses measured by two methods for PF13 (rho = 0.89) and for MSP1p19 (rho = 0.78). The ROC curves plotting specificity vs sensitivity of the two methods, used to calculate the best cut-off point, are shown for PF13 (c) and MSP1p19 (d).
Mentions: As illustrated in Figure 1, there was a significant (P <10-3) positive correlation between MFI and OD values for antibody responses to PF13 (Figure 1a, rho = 0.89) and to MSP1p19 (Figure 1b, rho = 0.78) monitored by the two methodologies. When including only positive responders (ie, individuals with OD-ratio >2), the correlation remained significantly positive (P < 10-3), rho = 0.80 and 0.65 for PF13 and MSP1p19, respectively. When stratifying by age group, antibody levels showed a similar degree of concordance of the two techniques in all age groups (<5, 5–10, 10–15, 15–29, and ≥30 years) for PF13 (rho = 0.89, 0.90, 0.83, 0.89, 0.85, respectively) and MSP1p19 (rho = 0.97, 0.68, 0.82, 0.80, 0.72, respectively).Figure 1

Bottom Line: Numerous Plasmodium falciparum antigens elicit humoral responses in humans living in endemic areas.Archived plasma samples collected before the rainy season from 217 villagers living in Ndiop, a Senegalese meso-endemic setting, were studied.This may reflect incomplete overlap of the epitopes presented in the two formats.

View Article: PubMed Central - PubMed

Affiliation: Institut Pasteur de Dakar, Unité d'Immunologie, Dakar, Sénégal. perraut@pasteur.sn.

ABSTRACT

Background: Numerous Plasmodium falciparum antigens elicit humoral responses in humans living in endemic areas. Use of multiplex assays is a convenient approach to monitor the antibody response against multiple antigens, but to integrate multiplex assay-derived data with datasets, generated previously using ELISA, comparative studies are needed. This work compares antibody responses to two P. falciparum antigens monitored using both technologies.

Methods: The IgG response against the merozoite surface protein-1 PfMSP1p19 and the PF13-DBL1α1 domain of the P. falciparum Erythrocyte Membrane Protein1, expressed by the rosette-forming parasite 3D7/PF13 (PF13), was investigated using ELISA and a MAGPIX®-Luminex duplex assay. Archived plasma samples collected before the rainy season from 217 villagers living in Ndiop, a Senegalese meso-endemic setting, were studied. ROC analysis was used to define the optimal antibody measure readout. Association of antibody levels with protection against clinical malaria was analysed using Poisson regression in a retrospective study from active case detection records performed during the 5.5-month transmission season that followed blood sampling.

Results: There was a strong positive correlation (P<10(-3)) between ELISA and MAGPIX®-Luminex-MFI (median fluorescence intensity) values for antibody to PfMSP1p19 (rho=0.78) and PF13-DBL1α1 (rho=0.89), with a similar degree of concordance in all age groups. Antibody levels to both antigens were high but displayed a different age-associated pattern. Independent age-adjusted Poisson regression analysis showed a significant association with protection only for IgG responses to MSP1p19 (P<0.01 RR=0.71 [0.53-0.93]) measured by ELISA.

Conclusion: The individual ELISA and duplex-MAGPIX assays provide a concordant evaluation of age-associated antibody responses to MSP1p19 and PF13-DBL1α1, irrespective of the formulation of antibody levels (values, ratios or ROC-adjusted figures) but do diverge with regard to the association of antibody levels with clinical protection in age-adjusted models. This may reflect incomplete overlap of the epitopes presented in the two formats. Further development for multiplex assessment of antibody responses to a larger panel of antigens with the robust and cost effective MAGPIX®-Luminex technology is warranted.

Show MeSH
Related in: MedlinePlus