Project description:Liver stage of malaria parasite exports SLTRiP and PB268 to the cytosol of parasite infected host cell. To know the host genes perturbed by WT-PBANKA, SLTRiP-KO and PB268-KO parasite growth, we did transcriptomic sequencing of infected host cells. We did mRNA sequencing of four samples for comparative analysis of WT and PB-knockout parasites infected host cells at 22 hours of post sporozoites infection.
Project description:Liver stage of malaria parasite exports SLTRiP and PB268 to the cytosol of parasite infected host cell. To know the host genes perturbed by WT-PBANKA, SLTRiP-KO and PB268-KO parasite growth, we did transcriptomic sequencing of infected host cells. We did mRNA sequencing of four samples for comparative analysis of WT and PB-knockout parasites infected host cells at 22 hours of post sporozoites infection. mRNA profiles of Plasmodium PBANKA, PBSLTRiP-KO, PB268-KO parasite infected and uninfected HepG2 cells after 22hrs of sporozoites infections were generated by deep sequencing using Illumina GAIIx.
Project description:The number of patients infected with simian malaria is increasing in many countries in Southeast Asia. The behavior of humans, monkeys, and vectors influences their interactions with each other and is the most important risk factor of zoonotic malaria infection. However, no serum proteomics study has been conducted in wild macaques. The present study was performed using a proteomics approach to explore the protein expression profile of wild stump-tailed macaques (Macaca arctoides) infected with malaria parasites.
Project description:Malaria is a disease with diverse symptoms depending on host immune status and pathogenicity of Plasmodium parasites. The continuous parasite growth within a host suggests mechanisms of immune evasion and/or inhibition. To identify pathways commonly inhibited by malaria infection, we infected C67BL/6 mice with four Plasmodium yoelii strains causing different disease phenotypes and 24 progeny of a genetic cross. mRNAs from mouse spleens day 1 and/or day 4 post infection (p.i.) were hybridized to a mouse microarray to identify activated or inhibited pathways, upstream regulators, and linkages to parasite genetic loci. Strong interferon responses were observed after infection with N67 strain, whereas initial inhibition and later activation of hematopoiesis pathways were found after infection with 17XNL parasite. Inhibition of pathways such as Th1 activation, dendritic cell (DC) maturation, and NFAT immune regulation were observed in mice infected with all the parasite strains day 4 p.i., suggesting universally inhibited immune pathways. Treatment of infected mice with antibodies against T cell receptors OX40 or CD28 to activate malaria-inhibited pathways enhanced host survival. Controlled activation of these pathways may provide important strategies for better disease management and for developing an effective vaccine.
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>
Project description:Paper: Transcriptional Profiling of Plasmodium falciparum Parasites from Patients with Severe Malaria Identifies Distinct Low vs. High Parasitemic Clusters Milner et al Plos One July 18, 2012 Plasmodium falciparum Parasites from Patients with Severe Malaria
Project description:The objective of this study is to characterize the overall transcriptome of P. falciparum NF54 derived from a controlled-human malaria infection (CHMI) study. Healthy, immunologically naïve human volunteers were infected intradermally or intravenously with different dosages of Plasmodium falciparum sporozoites (Sanaria® PfSPZ Challenge). Parasites were isolated from these volunteers and subjected to a range of in vitro culture generation prior to RNA collection.
Project description:The dry season is a major challenge for Plasmodium falciparum parasites in many malaria endemic regions, where water availability limits mosquitoes to only part of the year. How P. falciparum bridges two transmission seasons months apart, without being cleared by the host or compromising host survival is poorly understood. Here we show that low levels of P. falciparum parasites persist in the blood of asymptomatic Malian individuals during the 5- to 6-month dry season, rarely causing symptoms and minimally affecting the host immune response. Parasites isolated during the dry season are transcriptionally distinct from those of subjects with febrile malaria in the transmission season, reflecting longer circulation within each replicative cycle, of parasitized erythrocytes without adhering to the vascular endothelium. Low parasite levels during the dry season are not due to impaired replication, but rather increased efficiency of splenic clearance of longer-circulating infected erythrocytes. We propose that P. falciparum virulence in areas of seasonal malaria transmission is regulated so that the parasite decreases its endothelial binding capacity, allowing increased splenic clearance and enabling several months of subclinical parasite persistence.
Project description:After entering their mammalian host via the bite of an Anopheles mosquito, Plasmodium sporozoites migrate to the liver where they traverse several hepatocytes before invading the one inside which they will develop and multiply into thousands of merozoites. Although this constitutes an essential step in malaria infection, the requirements of Plasmodium parasites in liver cells and how they use the host cell for their own survival and development are poorly understood. To gain new insights into the molecular host-parasite interactions that take place during malaria liver infection, we have used high-throughput microarray technology to determine the transcriptional profile of P. yoelii-infected hepatocytes that were collected from P. yoelii-infected mice 24 and 40 h after infection. This in vivo microarray expression was compared with the microarray analysis of in vitro infected hepatoma cells infected with closely related rodent malaria parasite P. berghei. Differential expression patterns for host genes identify genes and pathways involved in the host response to rodent Plasmodium parasites. Keywords: gene expression
Project description:CD4+ T cells are critical for defense against the Plasmodium parasites that cause malaria. To better understand CD4+ T cell effector mechanisms during malaria, we performed microarray analysis of CD4+ T cells from naïve and infected mice. Comparison of activated (CD44 hi CD62L lo) CD4+ T cells from infected mice to bulk CD4+ T cells from naïve mice revealed a subset of genes that were upregulated by infection with Plasmodium chabaudi. These results help generate a more complete picture of CD4+ T cell function in malaria.