Molecular Hallmarks of Experimentally Acquired Immunity to Malaria [Pilot Study]
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ABSTRACT:
ORGANISM(S): Homo sapiens
SUBMITTER: Ravi Sanka
PROVIDER: E-GEOD-50957 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
Similar Datasets
Project description:Sterile immunity to Plasmodium falciparum infection can be induced experimentally in humans after few exposures. An example is the induction of immunity using whole parasites by exposure of malaria-naive volunteers to infectious mosquito bites while using chloroquine prophylaxis (CPS immunization). Chloroquine kills blood-stage parasites but leaves liver-stage parasites unaffected, thereby exposing the liver-stage and early blood-stage antigens to the immune system. Upon subsequent challenge, volunteers are completely protected from infection, but protective efficacy decreases when fewer infectious mosquito bites are used for CPS immunization. Efforts to understand the mechanisms of this immunity, and how it differs from naturally-acquired immunity, may provide critical insights that could aid malaria vaccine development. In this pilot study, transcriptomic features are derived from blood samples collected before and after challenge with infectious mosquito bites.
2013-09-18 | GSE50957 | GEO
Project description:<p>Description:<br/> Experimental exposure to malaria parasites can lead to development of protective immunity, providing a foothold for the development of a malaria vaccine. The goal of this study is to investigate immune transcriptional profiles associated with malaria protective immune responses induced by experimental Chemo-Prophylaxis and Sporozoites (CPS) immunization of P. <i>falciparum</i>-naive human volunteers. Samples for this study were obtained from a CPS-immunization study conducted in 2011 (ClinicalTrials.gov Identifier: NCT01218893), where healthy volunteers received CPS-immunization with bites from different numbers of P. <i>falciparum</i>-infected mosquitoes (three times 15 (n=5), 10 (n=9) or 5 (n=10)). Five control subjects received uninfected mosquito bites under chloroquine prophylaxis. Fifteen weeks after discontinuation of chloroquine prophylaxis, all volunteers were challenged by exposure to infected mosquito bites. </p> <p>Study Design:<br/> A maximum of 30 volunteers were divided into four groups. All volunteers received weekly chloroquine prophylaxis for a period of 13 weeks (91 days). During these 13 weeks, on days 8, 36 and 64 they were exposed to the bites of 15 mosquitoes. Group 1 (n=5, positive control) received three CPS immunizations by 15 mosquitoes infected with P. falciparum sporozoites. Group 2 (n=10) received three times 10 bites from infected mosquitoes and 5 bites from uninfected mosquitoes. Group 3 (n=10) received three times 5 bites from infected mosquitoes and 10 bites from uninfected mosquitoes. Group 4 (n=5), the negative control, received three placebo immunizations with 15 bites of uninfected mosquitoes. Fifteen weeks after discontinuation of chloroquine prophylaxis, all 30 volunteers were challenged at day 196 by the bites of 5 infectious mosquitoes and followed for 21 days. All subjects were treated with chloroquine 21 days after challenge or whenever they had a positive thick smear during that period. </p>
| phs001346 | dbGaP
Project description:Background: The mosquito Anopheles gambiae is a major vector of human malaria. Increasing evidence indicates that blood cells (hemocytes) comprise an essential arm of the mosquito innate immune response against both bacteria and malaria parasites. To further characterize the role of hemocytes in mosquito immunity, we undertook the first genome-wide transcriptomic analyses of adult female An. gambiae hemocytes following infection by two species of bacteria and a malaria parasite. Results: We identified 4047 genes expressed in hemocytes, using An. gambiae genome-wide microarrays. While 279 transcripts were significantly enriched in hemocytes relative to whole adult female mosquitoes, 959 transcripts exhibited immune challenge-related regulation. The global transcriptomic responses of hemocytes to challenge with different species of bacteria and/or different stages of malaria parasite infection revealed discrete, minimally overlapping, pathogen-specific signatures of infection-responsive gene expression; 105 of these represented putative immunity-related genes including anti-Plasmodium factors. Of particular interest was the specific co-regulation of various members of the Imd and JNK immune signaling pathways during malaria parasite invasion of the mosquito midgut epithelium. Conclusion: Our genome-wide transcriptomic analysis of adult mosquito hemocytes reveals pathogen-specific signatures of gene regulation and identifies several novel candidate genes for future functional studies.
2011-10-31 | GSE33269 | GEO
Project description:To test the contributions of phagocytic immune cells to mosquito immunity, we depleted mosquito phagocytes using clodronate liposomes and then challenged mosquitoes with malaria parasites. Observing a large increase in infection intensity, the purpose of the RNA-seq experiment is to determine their effects of phagocyte depletion on mosquito immunity.
2020-04-10 | GSE116156 | GEO
Project description:Identifying immune correlates of protection and mechanisms of immunity accelerates and streamlines the development of vaccines. RTS,S/AS01E, the most advanced malaria vaccine, has moderate efficacy in African children. In contrast, immunization with sporozoites under antimalarial chemoprophylaxis (CPS immunization) can provide 100% sterile protection in naïve adults. We used systems biology approaches to identify correlates of vaccine-induced immunity based on transcriptomes of peripheral blood mononuclear cells from subjects immunized with RTS,S/AS01E or chemo-attenuated sporozoites stimulated with parasite antigens in vitro. Specifically, we used samples of subjects from two age cohorts and 3 African countries participating in an RTS,S/AS01E pediatric phase 3 trial and malaria-naïve subjects participating in a CPS trial. We identified both pre-immunization and post-immunization transcriptomic signatures correlating with protection. Signatures were validated in independent children and infants from the RTS,S/AS01E phase 3 trial and subjects from an independent CPS trial with high accuracies (>70%). Transcription modules revealed interferon, NF-B, TLR, and monocyte-related signatures associated with protection. Pre-immunization signatures suggest the potential for strategies to prime the immune system before vaccination towards improving vaccine immunogenicity and efficacy. Finally, signatures of protection could be useful to determine efficacy in clinical trials, accelerating vaccine candidate testing. Nevertheless, signatures should be tested more extensively across multiple cohorts and trials to demonstrate their universal predictive capacity.
2020-05-13 | GSE144826 | GEO
Project description:Many eukaryotic developmental and cell fate decisions are effected post-transcriptionally that mechanistically involve RNA binding proteins as regulators of translation of key mRNAs. In the unicellular eukaryote malaria parasite, Plasmodium, one of the most dramatic changes in cell morphology and function occurs during transmission between mosquito and human host. In the mosquito salivary glands, Plasmodium sporozoites are slender, motile and remain infectious for several weeks; only after transmission and liver cell invasion, does the parasite rapidly transform into a round, non-motile exo-erythrocytic form (EEF) that gives rise to thousands of infectious merozoites to be released into the blood stream. Here we demonstrate a Plasmodium homolog of the RNA binding protein, Pumilio, as a key regulator of the sporozoite to EEF transformation. In the absence of Pumilio-2 (Puf2) Plasmodium berghei sporozoites initiate early stage EEF development inside mosquito salivary glands with characteristic morphological changes; puf2- salivary gland sporozoites lose gliding motility, cell traversal ability and are less infective. Global expression profiling confirmed that transgenic parasites exhibit genome-wide transcriptional adaptations typical for Plasmodium intra-hepatic development. The data demonstrate that Puf2 is a key player in regulating developmental control, and imply that transformation of salivary gland-resident sporozoites into early liver stage parasites is regulated by a post-translational mechanism.
2010-11-01 | E-TABM-1067 | biostudies-arrayexpress
Project description:Background: The mosquito Anopheles gambiae is a major vector of human malaria. Increasing evidence indicates that blood cells (hemocytes) comprise an essential arm of the mosquito innate immune response against both bacteria and malaria parasites. To further characterize the role of hemocytes in mosquito immunity, we undertook the first genome-wide transcriptomic analyses of adult female An. gambiae hemocytes following infection by two species of bacteria and a malaria parasite. Results: We identified 4047 genes expressed in hemocytes, using An. gambiae genome-wide microarrays. While 279 transcripts were significantly enriched in hemocytes relative to whole adult female mosquitoes, 959 transcripts exhibited immune challenge-related regulation. The global transcriptomic responses of hemocytes to challenge with different species of bacteria and/or different stages of malaria parasite infection revealed discrete, minimally overlapping, pathogen-specific signatures of infection-responsive gene expression; 105 of these represented putative immunity-related genes including anti-Plasmodium factors. Of particular interest was the specific co-regulation of various members of the Imd and JNK immune signaling pathways during malaria parasite invasion of the mosquito midgut epithelium. Conclusion: Our genome-wide transcriptomic analysis of adult mosquito hemocytes reveals pathogen-specific signatures of gene regulation and identifies several novel candidate genes for future functional studies. In order to identify hemocyte-specific and immune-responsive transcripts, we first compared transcripts expressed in hemocytes from one day old sugar-fed mosquitoes to transcripts detected in whole mosquitoes of the same age and feeding status. This resulted in identification of the hemocyte-enriched transcriptome. We then compared hemocytes from 1 day old mosquitoes, 1 hour after immune challenge with heat-killed Escherichia coli or Micrococcus luteus, to control female mosquitoes injected with sterile PBS to determine the bacteria challenge responsive transcriptomes. We used heat-killed bacteria in these assays, because our primary interest was in identifying the bacterial responsive transcriptome and to avoid the potentially confounding effects of altered gene expression due to the lethal effects of a systemic infection associated with injection of living bacteria. Lastly, we compared hemocytes from mosquitoes at 24 hours and 19 days after ingestion of a blood meal infected with Plasmodium berghei to mosquitoes of the same age fed a non-infected blood meal to determine the ookinete and sporozoite infection responsive transcriptomes, respectively. This design resulted in a total of five experimental treatments. The following samples are not included in this submission: Hemo E coli vs. hemo unchallenged A Hemo E coli vs. hemo unchallenged B Hemo m luteus vs. hemo unchallenged A Hemo m luteus vs. hemo unchallenged B
2011-10-31 | E-GEOD-33269 | biostudies-arrayexpress
Project description:The main purpose of this article is to formulate a deterministic mathematical model for the transmission of malaria that considers two host types in the human population. The first type is called "non-immune" comprising all humans who have never acquired immunity against malaria and the second type is called "semi-immune". Non-immune are divided into susceptible, exposed and infectious and semi-immune are divided into susceptible, exposed, infectious and immune. We obtain an explicit formula for the reproductive number, R(0) which is a function of the weight of the transmission semi-immune-mosquito-semi-immune, R(0a), and the weight of the transmission non-immune-mosquito-non-immune, R(0e). Then, we study the existence of endemic equilibria by using bifurcation analysis. We give a simple criterion when R(0) crosses one for forward and backward bifurcation. We explore the possibility of a control for malaria through a specific sub-group such as non-immune or semi-immune or mosquitoes
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2018-08-22 | GSE116341 | GEO
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