Evaluation of Immunoglobulin G Responses to Plasmodium falciparum and Plasmodium vivax in Malian School Children Using Multiplex Bead Assay

Abstract

Abstract. Malaria serology through assaying for IgG against Plasmodium spp. antigens provides evidence into the infection history for an individual. The multiplex bead assay (MBA) allows for detection of IgG against multiple Plasmodium spp., and can be especially useful in many regions where Plasmodium falciparum is of primary clinical focus, but other species are co-endemic. Dried blood spots were collected from 805 Malian children attending 42 elementary schools in the regions of Mopti, Sikasso, Koulikoro, and Bamako capital district, and IgG assayed by MBA. As southern Mali is known to be holoendemic for P. falciparum, merozoite surface protein 1 19-kDa subunit (MSP-1 42 ) and apical membrane antigen 1 (AMA-1) antigens were included for serology against this parasite. Responses to these antigens both provided high estimates for lifetime exposure, with 730 (90%) children with IgG antibodies for MSP-1 42 , 737 (91%) for AMA-1, and 773 (96%) positive for either or both. Also included was the antigen Plasmodium vivax MSP-1 19 , against which 140 (17.4%) children were found to have antibodies. Increases in antibody titers with older age were clearly seen with the P. falciparum antigens, but not with the P. vivax antigen, likely indicating more of a sporadic, rather than sustained transmission for this species. The MBA provides effective opportunities to evaluate malaria transmission through serological analysis for multiple Plasmodium species.

Quality control of multiplex antibody detection in samples from large-scale surveys: the example of malaria in Haiti

“…4). The median and length of the IQR of y-inflection points was similar for Survey 1 and Survey 2 for most antigens; except for a smaller recorded Survey 2 median for MSP2_CH150/9 (i.e., below the 25 th percentile of Survey 1) as well as a larger Survey 2 IQR for PfMSP-1 19 , MSP2_CH150/9, SBP1 and to a lesser extent MSP2_Dd2. The length of the IQR for y-inflection points was generally highest in Survey 3.…”

“…2. Values on assay plates that fell outside of the 2 standard deviation (SD) range of mean responses for two out of three highly immunogenic antigens (GLURP-R2, PfAMA-1 and PfMSP-1 19 ) were selected to be repeated: 2 plates in Survey 1, 9 plates in Survey 2, and 2 plates in Survey 3 (13/387 total assay plates, 3.4%). Upon repetition, all 13 of these assay plates passed the QC check and provided useable serological data.…”

“…While for most antigens the median Survey 3 y-inflection point was similar to Survey 1 and 2, a smaller Survey 3 median (i.e., below the 25 th percentile of Survey 2) was recorded for MSP2_CH150/9, MSP2_Dd2, GEXP18 and borderline for SBP1. Standard curves for Pf, P. vivax (Pv) and P. malariae (Pm) MSP-1 19 antigens with the HP and NIBSC standard are shown in Supplementary Fig. 3.…”

Multiplex serologic testing within a cross-sectional lymphatic filariasis sentinel site survey in coastal Kenya reveals community-level differences in IgG antibody responses to parasitic diseases and vaccines

“…Serum dilutions were centrifuged at maximum speed to pellet the E. coli extract particulates immediately before use. Bloodspot dilutions were assayed in duplicate with antigen-coupled microsphere beads using a BioPlex 200 system platform (Bio-Rad, Hercules, CA) as previously described [21,23,25]. The average of the median fluorescent intensity values from the duplicate wells minus the background fluorescence from the buffer-only blank was reported as the "median fluorescence intensity minus background" (MFI-bg).…”

“…The MBA has successfully been used to simultaneously measure antibody responses to multiple parasitic diseases of public health importance as part of a vaccine-preventable disease serological survey in Cambodia [23]. The platform has also been used to simultaneously assess IgG responses to a panel of malaria antigens [24,25]. In the current study, the MBA platform was used for multiplex serosurveillance of diseases of public health importance by testing for antibodies against LF and several other parasitic diseases (malaria, schistosomiasis, ascariasis, strongyloidiasis) as well as seroprevalence to selected vaccinepreventable diseases (measles, diphtheria, and tetanus).…”