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Tassi Yunga S, Siriwardhana C, Fouda GG, Bobbili N, Sama G, Chen JJ, Leke RFG, Taylor DW. Characterization of the primary antibody response to Plasmodium falciparum antigens in infants living in a malaria-endemic area. Malar J 2022; 21:346. [PMCID: PMC9675181 DOI: 10.1186/s12936-022-04360-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Accepted: 11/03/2022] [Indexed: 11/21/2022] Open
Abstract
Background The primary antibody (Ab) response to Plasmodium falciparum is a critical step in developing immunity to malaria. Information on the initial Ab responses of babies in malaria-endemic areas is incomplete, in part, because babies receive maternal IgG via transplacental-transfer and usually become infected before maternal IgG wanes. The study aimed to identify the primary IgM and IgG Ab responses to malarial antigens in Cameroonian babies. Methods Infants (n = 70) living in a high malaria transmission area were followed from birth throughout the first year of life (mean 341 ± 42 days, an average of 8.5 time points per infant). Malaria infection was assessed by microscopy and PCR, and IgM and IgG antibodies (Abs) were measured using a multiplex immunoassay to AMA1, EBA-175, MSP1-42, MSP2, MSP3, RESA, LSA1, and CSP. Results The half-life of maternal IgG varied among the antigens, ranging from 0.7 to 2.5 months. The first infection of 41% of the babies was sub-microscopic and only 11 to 44% of the babies produced IgM to the above antigens; however, when the first infection was detected by microscopy, 59–82% of the infants made IgM Abs to the antigens. Infants were able to produce IgM even when maternal IgG was present, suggesting maternal Abs did not suppress the baby’s initial Ab response. Using longitudinal regression models that incorporated time-varying covariates, infants were found to produce IgG Ab to only AMA-1 when the first infection was sub-microscopic, but they produced IgG Abs to MSP1-42 (3D7, FVO), AMA1 (3D7, FVO) MSP2-FC27, MSP3, RESA, and LSA1, but not MSP 2-3D7, EBA-175, and CSP during their first slide-positive infection. Notably, the primary and secondary IgG responses were short-lived with little evidence of boosting. Conclusions The primary Ab response of babies who had maternal IgG was similar to that reported for primary infections in malaria-naïve adults. Supplementary Information The online version contains supplementary material available at 10.1186/s12936-022-04360-x.
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Affiliation(s)
- Samuel Tassi Yunga
- grid.410445.00000 0001 2188 0957Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street, Bioscience Building Suite 320, Honolulu, HI 96813 USA ,grid.5288.70000 0000 9758 5690Cancer Early Detection Advanced Research Center (CEDAR), School of Medicine, Knight Cancer Institute, Oregon Health & Science University, 2720 S. Moody Avenue, Portland, OR USA
| | - Chathura Siriwardhana
- grid.410445.00000 0001 2188 0957Department of Quantitative Health Sciences, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street, MEB411, Honolulu, HI 96813 USA
| | - Genevieve G. Fouda
- grid.5386.8000000041936877XDepartment of Pediatrics, Joan & Sanford I. Weill Medical College of Cornell University, New York, NY USA
| | - Naveen Bobbili
- grid.410445.00000 0001 2188 0957Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street, Bioscience Building Suite 320, Honolulu, HI 96813 USA
| | - Grace Sama
- grid.412661.60000 0001 2173 8504The Biotechnology Center, University of Yaoundé 1, Messa, BP 3851 Yaoundé, Cameroon
| | - John J. Chen
- grid.410445.00000 0001 2188 0957Department of Quantitative Health Sciences, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street, MEB411, Honolulu, HI 96813 USA
| | - Rose F. G. Leke
- grid.412661.60000 0001 2173 8504The Biotechnology Center, University of Yaoundé 1, Messa, BP 3851 Yaoundé, Cameroon
| | - Diane Wallace Taylor
- grid.410445.00000 0001 2188 0957Department of Tropical Medicine, Medical Microbiology and Pharmacology, John A. Burns School of Medicine, University of Hawaii at Manoa, 651 Ilalo Street, Bioscience Building Suite 320, Honolulu, HI 96813 USA
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Gibbs L, Fairfax KC. Altered Offspring Immunity in Maternal Parasitic Infections. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2022; 208:221-226. [PMID: 35017211 PMCID: PMC8769501 DOI: 10.4049/jimmunol.2100708] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 11/10/2021] [Indexed: 01/17/2023]
Abstract
Maternal infection during pregnancy is known to alter the development and function of offspring's immune system, leading to inappropriate immune responses to common childhood infections and immunizations. Although this is an expanding field, maternal parasitic infections remain understudied. Millions of women of reproductive age are currently at risk for parasitic infection, whereas many pregnant, chronically infected women are excluded from mass drug administration due partially to a lack of resources, as well as fear of unknown adverse fetal developmental outcomes. In areas endemic for multiple parasitic infections, such as sub-Saharan Africa, there are increased rates of morbidity and mortality for various infections during early childhood in comparison with nonendemic areas. Despite evidence supporting similar immunomodulatory effects between various parasite species, there is no clear mechanistic understanding of how maternal infection reprograms offspring immunity. This brief review will compare the effects of selected maternal parasitic infections on offspring immunity.
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Affiliation(s)
- Lisa Gibbs
- Department of Pathology, Division of Microbiology and Immunology, University of Utah, Salt Lake City Utah, USA
| | - Keke C. Fairfax
- Department of Pathology, Division of Microbiology and Immunology, University of Utah, Salt Lake City Utah, USA
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Does Antibody Avidity to Plasmodium falciparum Merozoite Antigens Increase with Age in Individuals Living in Malaria-Endemic Areas? Infect Immun 2021; 89:IAI.00522-20. [PMID: 33722929 DOI: 10.1128/iai.00522-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 03/07/2021] [Indexed: 11/20/2022] Open
Abstract
High-avidity antibodies (Abs) are acquired after a few Plasmodium falciparum infections in low transmission areas, but it remains unclear if Ab avidity to different merozoite antigens increases with age in individuals with persistent antigenemia and, if so, when a fully mature Ab response occurs. The study used plasma samples collected between 1996 and 1998 from 566 individuals aged 4 to 84 years in Simbok, Cameroon, where residents received an estimated 1.6 infectious mosquito bites/person/night. Plasma samples were examined for Ab levels (median fluorescence intensity [MFI]) and Ab avidity index (AI) (where AI = [MFI after treatment with 2 M NH4SCN/MFI without salt] × 100) using a bead-based multiplex immunoassay for recombinant AMA1, EBA-175, MSP1-42 (3D7, FVO), MSP2 (3D7, Fc27), and MSP3. Blood-smear positivity for P. falciparum declined with age from 54.3% at 4 to 5 years to 18% at 16 to 40 years and <11% at >40 years of age, although most individuals had submicroscopic parasitemia. Ab affinity maturation, based on age-related patterns of median AI, percentage of individuals with AI of ≥50, and strength of association between MFI and AI, occurred at different rates among the antigens; they developed rapidly before age 4 years for AMA1, increased gradually with age for EBA-175 and MSP1 until ∼16 to 25 years, but occurred negligibly for MSP2 and MSP3. In a hyperendemic area with perennial transmission, affinity maturation resulting in an increase in the proportion of high-avidity Abs occurred for some merozoite antigens, in parallel with a decline in malaria slide passivity, but not for others.
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Abstract
Purpose of Review Placental malaria is the primary mechanism through which malaria in pregnancy causes adverse perinatal outcomes. This review summarizes recent work on the significance, pathogenesis, diagnosis, and prevention of placental malaria. Recent Findings Placental malaria, characterized by the accumulation of Plasmodium-infected red blood cells in the placental intervillous space, leads to adverse perinatal outcomes such as stillbirth, low birth weight, preterm birth, and small-for-gestational-age neonates. Placental inflammatory responses may be primary drivers of these complications. Associated factors contributing to adverse outcomes include maternal gravidity, timing of perinatal infection, and parasite burden. Summary Placental malaria is an important cause of adverse birth outcomes in endemic regions. The main strategy to combat this is intermittent preventative treatment in pregnancy; however, increasing drug resistance threatens the efficacy of this approach. There are studies dissecting the inflammatory response to placental malaria, alternative preventative treatments, and in developing a vaccine for placental malaria.
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Omer SA, Adam I, Noureldien A, Elhaj H, Guerrero-Latorre L, Silgado A, Sulleiro E, Molina I. Congenital Malaria in Newborns Delivered to Mothers with Malaria-Infected Placenta in Blue Nile State, Sudan. J Trop Pediatr 2020; 66:428-434. [PMID: 31951264 DOI: 10.1093/tropej/fmz083] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Diagnosis of congenital malaria is complicated by the low density of the parasite circulating in the cord blood and/or the peripheral blood of the newborns. Molecular techniques are significantly more sensitive than blood smears in detecting low-level parasitemia. This study investigated the prevalence of congenital malaria by the use of the real-time polymerase chain reaction (real-time PCR) in 102 babies born to mothers with microscopically confirmed infected placenta from Blue Nile state, Sudan. At delivery time, placental, maternal peripheral and cord blood samples in addition to samples collected from the newborns' peripheral blood were examined for malaria infection using Giemsa-stained thick smear and parasite DNA detection by real-time PCR. The overall prevalence of congenital malaria includes the total babies with cord blood parasitaemia and peripheral blood parasitaemia was 18.6 and 56.8% using microscopy and real-time PCR, respectively. Even though all the neonates were aparasitaemic by microscopy, 19 (18.6%) of the babies had congenital malaria detected by real-time PCR, 15 (25.9%) of the babies with congenital malaria were born to mothers with both placental and peripheral blood malaria infections detected using the two techniques. Congenital malaria was significantly associated with cord blood malaria infections, maternal age and maternal haemoglobin level (p < 0.001). This first study investigating congenital malaria in Blue Nile state, Sudan shows that malaria-infected placenta resulted in infant and cord blood infections.
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Affiliation(s)
- Samia A Omer
- Department of Immunology and Biotechnology, Tropical Medicine Research Institute, Khartoum, Sudan
| | - Ishag Adam
- Department of Obstetrics and Gynecology, Unaizah College of Medicine, Qassim University, Unaizah, Kingdom of Saudi Arabia
| | - Ali Noureldien
- Department of Microbiology and Parasitology, Faculty of Medicine, University of Khartoum, Khartoum, Sudan
| | - Hadeel Elhaj
- Department of Immunology and Biotechnology, Tropical Medicine Research Institute, Khartoum, Sudan
| | | | - Aroa Silgado
- Microbiology Department, Universitat Autònoma de Barcelona, Barcelona, Catalunya, Spain
| | - Elena Sulleiro
- Microbiology Department, Universitat Autònoma de Barcelona, Barcelona, Catalunya, Spain
| | - Israel Molina
- Infectious Diseases Department, University Hospital Vall d'Hebron, Barcelona, Catalunya, Spain
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Park S, Nixon CE, Miller O, Choi NK, Kurtis JD, Friedman JF, Michelow IC. Impact of Malaria in Pregnancy on Risk of Malaria in Young Children: Systematic Review and Meta-Analyses. J Infect Dis 2020; 222:538-550. [PMID: 32219317 PMCID: PMC7377293 DOI: 10.1093/infdis/jiaa139] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 03/24/2020] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Our objective was to quantify the risk of acquiring malaria among progeny of women with malaria during pregnancy. METHODS We searched MEDLINE, EMBASE, CINAHL, and the Cochrane Library for eligible prospective studies. The primary predictor was malaria during pregnancy defined as placental malaria, parasitemia, clinical malaria, or pregnancy-associated malaria. Primary outcomes were parasitemia or clinically defined malaria of young children. We performed meta-analyses to pool adjusted risk estimates using a random-effects model. RESULTS Nineteen of 2053 eligible studies met inclusion criteria for the systemic review. Eleven of these studies were quantitative and were included in the meta-analyses. The pooled adjusted odds ratio (aOR) or adjusted hazard ratio (aHR) of malaria during pregnancy for detection of parasitemia in young children were 1.94 (95% confidence interval [CI], 0.93-4.07; P = .08) and 1.46 (95% CI, 1.07-2.00; P < .001), respectively. The pooled aOR or aHR for clinically defined malaria in young children were 2.82 (95% CI, 1.82-4.38; P < .001) and 1.31 (95% CI, 0.96-1.79; P = .09), respectively. CONCLUSIONS Our results confirmed that malaria during pregnancy significantly increased the overall risk of malaria in young children via indeterminate mechanisms and emphasize the urgent need to implement safe and highly effective strategies to prevent malaria during pregnancy.
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Affiliation(s)
- Sangshin Park
- Center for International Health Research, Rhode Island Hospital, Providence, Rhode Island, USA
- Department of Pediatrics, The Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA
- Graduate School of Urban Public Health, University of Seoul, Seoul, Republic of Korea
| | - Christina E Nixon
- Center for International Health Research, Rhode Island Hospital, Providence, Rhode Island, USA
- Department of Pathology and Laboratory Medicine, The Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA
| | - Olivia Miller
- Department of Global Health, DePauw University, Greencastle, Indiana, USA
| | - Nam-Kyong Choi
- Department of Health Convergence, Ewha Womans University, Seoul, Republic of Korea
| | - Jonathan D Kurtis
- Center for International Health Research, Rhode Island Hospital, Providence, Rhode Island, USA
- Department of Pathology and Laboratory Medicine, The Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA
| | - Jennifer F Friedman
- Center for International Health Research, Rhode Island Hospital, Providence, Rhode Island, USA
- Department of Pediatrics, The Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA
| | - Ian C Michelow
- Center for International Health Research, Rhode Island Hospital, Providence, Rhode Island, USA
- Department of Pediatrics, The Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA
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Taylor DW, Bobbili N, Kayatani A, Tassi Yunga S, Kidima W, Leke RFG. Measuring antibody avidity to Plasmodium falciparum merozoite antigens using a multiplex immunoassay approach. Malar J 2020; 19:171. [PMID: 32357882 PMCID: PMC7195780 DOI: 10.1186/s12936-020-03243-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 04/20/2020] [Indexed: 11/18/2022] Open
Abstract
Background Antibodies (Ab) play a significant role in immunity to Plasmodium falciparum malaria. Usually, following repeated exposure to pathogens, affinity maturation and clonal selection take place, resulting in increased antibody avidity. However, some studies suggest affinity maturation may not occur to malaria antigens in endemic areas. Information on development of antibody avidity is confusing and conflicting, in part, because different techniques have been used to measure avidity. Today, bead-based multiplex immunoassays (MIA) are routinely used to simultaneously quantitate antibody levels to multiple antigens. This study evaluated the feasibility of developing an avidity MIA with 5 merozoite antigens (AMA1, EBA-175, MSP1-42, MSP2, MSP3) that uses a single chaotropic concentration. Methods The most common ELISA protocols that used the chaotropic reagents guanidine HCl (GdHCl), urea, and ammonium thiocyanate (NH4SCN) were adapted to a multiplex MIA format. Then, different concentrations of chaotropes and incubation times were compared and results were expressed as an Avidity Index (AI), i.e., percentage of antibody remaining bound in the presence of chaotrope. Experiments were conducted to (i) identify the assay with the widest range of AI (discriminatory power), (ii) determine the amount of chaotrope needed to release 50% of bound Ab using plasma from adults and infants, and (iii) evaluate assay repeatability. Results Overall, 4 M GdHCl and 8 M urea were weaker chaotropes than 3 M NH4SCN. For example, they failed to release significant amounts of Ab bound to MSP1-42 in adult plasma samples; whereas, a range of AI values was obtained with NH4SCN. Titration of NH4SCN revealed that 2 M NH4SCN gave the widest range of AI for the 5 antigens. Binding studies using plasma from 40 adults and 57 1-year old infants in Cameroon showed that 2.1 M ± 0.32 (mean ± SD) NH4SCN (adults) and 1.8 M ± 0.23 M (infants) released 50% of bound Ab from the merozoite antigens. Conclusions An avidity MIA is feasible for the 5 merozoite antigens that uses a single concentration (2 M) of NH4SCN. The assay provides a simple method to quickly obtain information about Ab quantity and quality in the acquisition of immunity to malaria in endemic populations.
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Affiliation(s)
- Diane Wallace Taylor
- Department of Tropical Medicine, Medical Microbiology, and Pharmacology, John A. Burns School of Medicine, University of Hawaii, 561 Ilalo Street, Honolulu, HI, 96813, USA.
| | - Naveen Bobbili
- Department of Tropical Medicine, Medical Microbiology, and Pharmacology, John A. Burns School of Medicine, University of Hawaii, 561 Ilalo Street, Honolulu, HI, 96813, USA
| | - Alex Kayatani
- Department of Tropical Medicine, Medical Microbiology, and Pharmacology, John A. Burns School of Medicine, University of Hawaii, 561 Ilalo Street, Honolulu, HI, 96813, USA
| | - Samuel Tassi Yunga
- Department of Tropical Medicine, Medical Microbiology, and Pharmacology, John A. Burns School of Medicine, University of Hawaii, 561 Ilalo Street, Honolulu, HI, 96813, USA
| | - Winifrida Kidima
- Department of Tropical Medicine, Medical Microbiology, and Pharmacology, John A. Burns School of Medicine, University of Hawaii, 561 Ilalo Street, Honolulu, HI, 96813, USA
| | - Rose F G Leke
- Faculty of Medicine and Biomedical Sciences, The Biotechnology Center, University of Yaoundé 1, Yaoundé, Cameroon
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Kakuru A, Staedke SG, Dorsey G, Rogerson S, Chandramohan D. Impact of Plasmodium falciparum malaria and intermittent preventive treatment of malaria in pregnancy on the risk of malaria in infants: a systematic review. Malar J 2019; 18:304. [PMID: 31481075 PMCID: PMC6724246 DOI: 10.1186/s12936-019-2943-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 08/28/2019] [Indexed: 09/16/2023] Open
Abstract
Background Studies of the association between malaria in pregnancy (MiP) and malaria during infancy have provided mixed results. A systematic review was conducted to evaluate available evidence on the impact of Plasmodium falciparum malaria infection during pregnancy, and intermittent preventive treatment of malaria during pregnancy (IPTp), on the risk of clinical malaria or parasitaemia during infancy. Methods MEDLINE, EMBASE, Global Health, and Malaria in Pregnancy Library databases were searched from inception to 22 May 2018 for articles published in English that reported on associations between MiP and malaria risk in infancy. Search terms included malaria, Plasmodium falciparum, pregnancy, placenta, maternal, prenatal, foetal, newborn, infant, child or offspring or preschool. Randomized controlled trials and prospective cohort studies, which followed infants for at least 6 months, were included if any of the following outcomes were reported: incidence of clinical malaria, prevalence of parasitaemia, and time to first episode of parasitaemia or clinical malaria. Substantial heterogeneity between studies precluded meta-analysis. Thus, a narrative synthesis of included studies was conducted. Results The search yielded 14 published studies, 10 prospective cohort studies and four randomized trials; all were conducted in sub-Saharan Africa. Infants born to mothers with parasitaemia during pregnancy were at higher risk of malaria in three of four studies that assessed this association. Placental malaria detected by microscopy or histology was associated with a higher risk of malaria during infancy in nine of 12 studies, but only one study adjusted for malaria transmission intensity. No statistically significant associations between the use of IPTp or different IPTp regimens and the risk of malaria during infancy were identified. Conclusion Evidence of an association between MiP and IPTp and risk of malaria in infancy is limited and of variable quality. Most studies did not adequately adjust for malaria transmission intensity shared by mothers and their infants. Further research is needed to confirm or exclude an association between MiP and malaria in infancy. Randomized trials evaluating highly effective interventions aimed at preventing MiP, such as IPTp with dihydroartemisinin–piperaquine, may help to establish a causal association between MiP and malaria in infancy.
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Affiliation(s)
- Abel Kakuru
- Infectious Diseases Research Collaboration, P.O Box 7475, Kampala, Uganda. .,London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.
| | - Sarah G Staedke
- London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Grant Dorsey
- University of California San Francisco, San Francisco, CA, USA
| | - Stephen Rogerson
- Department of Medicine at the Doherty Institute, University of Melbourne, 792 Elizabeth Street, Melbourne, VIC, 3000, Australia
| | - Daniel Chandramohan
- London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
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Morffy Smith CD, Gong M, Andrew AK, Russ BN, Ge Y, Zadeh M, Cooper CA, Mohamadzadeh M, Moore JM. Composition of the gut microbiota transcends genetic determinants of malaria infection severity and influences pregnancy outcome. EBioMedicine 2019; 44:639-655. [PMID: 31160271 PMCID: PMC6606560 DOI: 10.1016/j.ebiom.2019.05.052] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 05/23/2019] [Accepted: 05/24/2019] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Malaria infection in pregnancy is a major cause of maternal and foetal morbidity and mortality worldwide. Mouse models for gestational malaria allow for the exploration of the mechanisms linking maternal malaria infection and poor pregnancy outcomes in a tractable model system. The composition of the gut microbiota has been shown to influence susceptibility to malaria infection in inbred virgin mice. In this study, we explore the ability of the gut microbiota to modulate malaria infection severity in pregnant outbred Swiss Webster mice. METHODS In Swiss Webster mice, the composition of the gut microbiota was altered by disrupting the native gut microbes through broad-spectrum antibiotic treatment, followed by the administration of a faecal microbiota transplant derived from mice possessing gut microbes reported previously to confer susceptibility or resistance to malaria. Female mice were infected with P. chabaudi chabaudi AS in early gestation, and the progression of infection and pregnancy were tracked throughout gestation. To assess the impact of maternal infection on foetal outcomes, dams were sacrificed at term to assess foetal size and viability. Alternatively, pups were delivered by caesarean section and fostered to assess neonatal survival and pre-weaning growth in the absence of maternal morbidity. A group of dams was also euthanized at mid-gestation to assess infection and pregnancy outcomes. FINDINGS Susceptibility to infection varied significantly as a function of source of transplanted gut microbes. Parasite burden was negatively correlated with the abundance of five specific OTUs, including Akkermansia muciniphila and OTUs classified as Allobaculum, Lactobacillus, and S24-7 species. Reduced parasite burden was associated with reduced maternal morbidity and improved pregnancy outcomes. Pups produced by dams with high parasite burdens displayed a significant reduction in survival in the first days of life relative to those from malaria-resistant dams when placed with foster dams. At midgestation, plasma cytokine levels were similar across all groups, but expression of IFNγ in the conceptus was elevated in infected dams, and IL-10 only in susceptible dams. In the latter, transcriptional and microscopic evidence of monocytic infiltration was observed with high density infection; likewise, accumulation of malaria haemozoin was enhanced in this group. These responses, combined with reduced vascularization of the placenta in this group, may contribute to poor pregnancy outcomes. Thus, high maternal parasite burden and associated maternal responses, potentially dictated by the gut microbial community, negatively impacts term foetal health and survival in the early postnatal period. INTERPRETATION The composition of the gut microbiota in Plasmodium chabaudi chabaudi AS-infected pregnant Swiss Webster mice transcends the outbred genetics of the Swiss Webster mouse stock as a determinant of malaria infection severity, subsequently influencing pregnancy outcomes in malaria-exposed progeny. FUND: Research reported in this manuscript was supported by the University of Florida College of Veterinary Medicine (JMM, MM, and MG), the National Institute of Allergy and Infectious Diseases, the National Institute of Diabetes and Digestive and Kidney Diseases, and the Eunice Kennedy Shriver National Institute of Child Health and Human Development of the National Institutes of Health under award numbers T32AI060546 (to CDMS), R01HD46860 and R21AI111242 (to JMM), and R01 DK109560 (to MM). MG was supported by Department of Infectious Diseases and Immunology and University of Florida graduate assistantships. AA was supported by the 2017-2019 Peach State LSAMP Bridge to the Doctorate Program at the University of Georgia (National Science Foundation, Award # 1702361). The content is solely the responsibility of the authors and does not necessarily represent official views of the Eunice Kennedy Shriver National Institute of Child Health and Human Development, the National Institute of Allergy and Infectious Diseases, the National Institute of Diabetes and Digestive and Kidney Diseases, or the National Institutes of Health.
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Affiliation(s)
- Catherine D Morffy Smith
- Department of Infectious Diseases and the Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, United States
| | - Minghao Gong
- Department of Infectious Diseases and Immunology, University of Florida, Gainesville, FL, United States
| | - Alicer K Andrew
- Department of Infectious Diseases and the Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, United States
| | - Brittany N Russ
- Department of Infectious Diseases and Immunology, University of Florida, Gainesville, FL, United States
| | - Yong Ge
- Department of Infectious Diseases and Immunology, University of Florida, Gainesville, FL, United States
| | - Mojgan Zadeh
- Department of Infectious Diseases and Immunology, University of Florida, Gainesville, FL, United States
| | - Caitlin A Cooper
- Department of Infectious Diseases and the Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, United States
| | - Mansour Mohamadzadeh
- Department of Infectious Diseases and Immunology, University of Florida, Gainesville, FL, United States
| | - Julie M Moore
- Department of Infectious Diseases and the Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, United States.
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