Selection of Antibody Responses Associated With Plasmodium falciparum Infections in the Context of Malaria Elimination

Abstract

van den Hoogen et al.Plasmodium falciparum Antibodies in Elimination n = 3,204)-Etramp 5 ag 1 and GLURP-R0 (area-under-the-curve, AUC, 0.892 and 0.825, respectively)-was confirmed in the test dataset (remaining one-third of the dataset; n = 1,652, AUC 0.903 and 0.848, respectively). As no further improvement was seen by combining seropositivity to GLURP-R0 and Etramp 5 ag 1 (p = 0.266), seropositivity to Etramp 5 ag 1 alone was selected as representative of current or recent exposure to malaria. The validation of antibody responses associated with these exposure histories simplifies analyses and interpretation of antibody data and facilitates the application of results to evaluate programs.

Framework for Characterizing Longitudinal Antibody Response in Children After Plasmodium falciparum Infection

“…On the other end of the spectrum, responses to the GLURP antigens were also substantial, but with rapid decay. An estimated half-life of around 10 days suggests that the presence of a strong GLURP response is evidence of active or very recent infection ( 43 ). Some vaccine candidates showed good antibody induction by infection (e.g., PfAMA1, Rh2, PfMSP1, GLURP), whereas others had a weaker response (e.g., RH5, CSP), which has been reported in other populations ( 39 ).…”

Effect of biannual azithromycin distribution on antibody responses to malaria, bacterial, and protozoan pathogens in Niger

“…The panel included malaria antigens to various stages of P. falciparum infection, including sporozoite (CSP), hepatocyte (LSA1), merozoite (GLURP-R0) and erythrocyte (MSP-1 19 , AMA1, HRP2), with MSP-1 19 and AMA1 thought to induce longer-lived IgG responses compared with other included P. falciparum antigens 12 . Species specific MSP-1 19 was used to detect P. vivax , P. malariae, P. ovale 10 .…”

“…The IgG panel was selected from a larger library of possible antigens that members of our team had previously developed for integrated serologic surveillance in low resource settings and could serve as plausible endpoints for mass azithromycin treatment 8 – 11 . The P. falciparum , panel included a mix of antigens known to induce both long-lived (MSP-1, AMA1) and short-lived (GLURP-R0, LSA1, CSP, and HRP2) IgG responses 12 , 13 . We hypothesized that, compared to placebo, children who received azithromycin would have lower levels of infection and thus lower IgG responses to the pathogens measured.…”

Risk Factors for Malaria Infection and Seropositivity in the Elimination Area of Grand’Anse, Haiti: A Case–Control Study among Febrile Individuals Seeking Treatment at Public Health Facilities

“…21 A binary metric describing the presence of malaria antibodies representing recent exposure was defined as positivity to one antigen target (Etramp 5 Ag 1), whereas an indicator of longer term malaria exposure was defined as positivity against at least one of two antigens (PfAMA1 and PfMSP1-19). 19 These two binary metrics were used to define additional case and control definitions for recent and cumulative exposure to P. falciparum. Serology data from children younger than 1 year were not retained because of potential confounding from maternal antibodies.…”

“…For all participants who provided DBS, serum antibody levels to a panel of 19 Plasmodium antigens were determined using the multiplex bead assay (MBA) at the National Public Health Laboratory (Laboratoire National de la Santé Publique [LNSP]) in Port-au-Prince. 17 – 19 Briefly, antigens were covalently coupled to unique bead regions as previously described, 20 and then processed for multiplex antibody (IgG) detection using a one-step protocol. 18 Median fluorescence intensity (MFI) was recorded for each sample and corrected for background reactivity, and then log-transformed.…”