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

Ronald Perraut (1) , Vincent Richard (2) , Marie-Louise Varela (1) , Jean-François Trape (3, 4) , Micheline Guillotte (5) , Adama Tall (2) , Aïssatou Toure (1) , Cheikh Sokhna (3) , Inès Vigan-Womas (5) , Odile Mercereau-Puijalon (5)

1 Institut Pasteur de Dakar
2 Unité d'Epidémiologie des Maladies Infectieuses
3 IRD Hann Maristes - Institut de recherche pour le développement [Dakar, Sénégal]
4 URMITE - Unité de Recherche sur les Maladies Infectieuses Tropicales Emergentes
5 IP - Institut Pasteur [Paris]

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.

Mots clés: Malaria; Plasmodium falciparum; ELISA; IgG; Surface antigens; MSP1p19; PfEMP1-PF13; Multiplex; MAGPIX; Senegal; Ndiop

Domaines: Immunité adaptative; Maladies infectieuses; Santé publique et épidémiologie

Ronald Perraut, Vincent Richard, Marie-Louise Varela, Jean-François Trape, Micheline Guillotte, et al.. 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. Malaria Journal, 2014, 13, pp.410. ⟨10.1186/1475-2875-13-410⟩. ⟨hal-02937187⟩