RECOMBINANT MALARIAL PYRIMIDINE ENZYMES AS DRUG TARGETS
Funder
National Health and Medical Research Council
Funding Amount
$229,750.00
Summary
Malarial parasites have now developed resistance to most of the available drugs and there is an urgent need for drugs with new mechanisms of action. Institutions collaborating on the Malarial Genome Project have sequenced the majority of DNA in the 14 chromosomes. The nucleotide sequence available on the internet contains thousands of open reading frames (ORFs) which encode proteins essential for survival of the parasite. Many of these proteins are enzymes which are suitable targets for drug dev ....Malarial parasites have now developed resistance to most of the available drugs and there is an urgent need for drugs with new mechanisms of action. Institutions collaborating on the Malarial Genome Project have sequenced the majority of DNA in the 14 chromosomes. The nucleotide sequence available on the internet contains thousands of open reading frames (ORFs) which encode proteins essential for survival of the parasite. Many of these proteins are enzymes which are suitable targets for drug development. A knowledge of the molecular architecture of the active site of such enzymes provides a template for drug design. The malarial parasite, Plasmodium falciparum, can only synthesise pyrimidine nucleotides for DNA via the de novo pyrimidine pathway. We have cloned the genes encoding three of the enzymes of the de novo pathway using sequence information from the Malarial Genome Project. Dihydroorotase, orotate phosphoribosyltransferase, and OMP decarboxylase, catalyse reactions 3, 5 and 6 of the pathway. We have expressed these enzymes in the bacterium Escherichia coli enabling large-scale production of these drug targets. We propose to characterise the catalytic and inhibitory properties of these enzymes, and grow protein crystals for determination of atomic structures by x-ray diffraction. The structures will provide templates for rational design of new antimalarial drugs. In a second approach for develoment of new drugs, the 3 malarial enzymes will be screened against chemical libraries for inhibition of catalytic activity. The initial screen will utilise a high throughput Biacore 3000 instrument which detects strong interactions between a target enzyme and candidate inhibitors. A thorough knowledge of the catalytic mechanisms, the three-dimensional structures and novel first generation inhibitors of these 3 malarial target enzymes, will provide a strong basis for development of new antimalarial drugs.Read moreRead less
Antibodies Against Erythrocyte Invasion Ligands Of Plasmodium Falciparum And Protection From Malaria
Funder
National Health and Medical Research Council
Funding Amount
$358,184.00
Summary
Malaria is a leading cause of childhood death globally. Malaria parasites infect red blood cells and multiply inside them, resulting in severe illness if untreated. Currently there is no vaccine available and effective treatments are limited. In studies of children in Africa and PNG, we aim to identify immune responses that block infection and growth of malaria in the blood. With this knowledge, vaccines can be designed that target malaria to prevent serious illness and death.
Structure And Interactions Of The Malarial Vaccine Candidate AMA1
Funder
National Health and Medical Research Council
Funding Amount
$351,000.00
Summary
Malaria remains one the most lethal infectious diseases in the world today. It is directly responsible for 1-2 million deaths annually, many of these in children under 5 years of age. More than 300 million clinical cases are reported annually and over 40% of the global population (in excess of 2 billion people) are at risk. There is an urgent need for a vaccine against this disease, particularly because of the recent increase in forms of the parasite resistant to many of the best anti-malarial d ....Malaria remains one the most lethal infectious diseases in the world today. It is directly responsible for 1-2 million deaths annually, many of these in children under 5 years of age. More than 300 million clinical cases are reported annually and over 40% of the global population (in excess of 2 billion people) are at risk. There is an urgent need for a vaccine against this disease, particularly because of the recent increase in forms of the parasite resistant to many of the best anti-malarial drugs. AMA1 is an asexual stage antigen and a leading vaccine candidate. Little is known about the function of this protein, but it has been proposed to play a role in invasion of red blood cells. A clearer understanding of the structure of parasite antigens such as AMA1 that induce a protective response in infected individuals would provide a stimulus to research into recombinant antigens as vaccines and a deeper understanding of host-parasite interactions. The aims of this project are to determine the three-dimensional structures of the three major structural domains of AMA1 and of the complete AMA1 antigen. We shall also determine the structures, both in aqueous solution and bound to AMA1, of small peptides identified by phage display as being capable of binding to AMA1 and blocking parasite entry into red blood cells. The overall goal of this work is to determine the structure of AMA1 and define the structural basis for its interaction with small peptides capable of blocking its activity as well as the structural features necessary for AMA1 to react with protective antibodies. The structure of AMA1 will provide a molecular basis for the design of engineered antigens capable of eliciting a protective immune response against AMA1. The inhibitory peptide structures will likewise provide a molecular basis for the design of non-peptidic blockers of AMA1. Either or both of these may be useful therapeutics leads in the fight against malaria.Read moreRead less
Structure And Interactions Of The Malarial Surface Antigen AMA1
Funder
National Health and Medical Research Council
Funding Amount
$242,545.00
Summary
Malaria remains one of the most serious infectious diseases in the world today, being responsible for 1-2 million deaths annually. There is an urgent need for a vaccine against this disease, particularly because of the recent increase in forms of the parasite resistant to many of the best anti-malarial drugs. A clearer understanding of the structure of antigens in the parasite that induce a protective response in infected individuals would provide a stimulus to research into recombinant antigens ....Malaria remains one of the most serious infectious diseases in the world today, being responsible for 1-2 million deaths annually. There is an urgent need for a vaccine against this disease, particularly because of the recent increase in forms of the parasite resistant to many of the best anti-malarial drugs. A clearer understanding of the structure of antigens in the parasite that induce a protective response in infected individuals would provide a stimulus to research into recombinant antigens as vaccines and a deeper understanding of the host-parasite interaction. AMA1 is an asexual stage antigen and a leading vaccine candidate. Little is known about the function of this protein, but it has been proposed to play a role in invasion of red blood cells. The specific aims of this project are to determine the three-dimensional structures of the three major structural domains of AMA1 and of the complete AMA1 ectodomain. The interaction of one or more of these domains with Fab fragments of protective antibodies raised against intact AMA1 will then be investigated. We also intend to determine the conformations, both in aqueous solution and bound to AMA1, of oligopeptides identified by phage display as binding to AMA1 and blocking its binding to red blood cells. The overall goals of this work are to determine the structure of AMA1 and to define the structural basis for its interaction with antibodies and small peptides that are capable of blocking its activity. This information will provide a molecular basis for the design of either synthetic antigens capable of eliciting a protective immune response against AMA1 or peptidomimetic inhibitors of AMA1. Either or both of these may be useful in the prevention or treatment of malaria.Read moreRead less
Assessment Of Transgenic Plants Expressing Malaria Antigens As A Means Of Inducing Protective Immunity
Funder
National Health and Medical Research Council
Funding Amount
$112,000.00
Summary
Malaria infection of humans is one of the most important and deadly infectious diseases in the world, killing more than two million people each year. Traditionally, drugs and insecticides have been used to treat the disease and control its spread. Unfortunately, both of these have become much less effective and there now exist untreatable cases of malaria. Alternative control measures are urgently needed and this project focusses on the development of such an alternative, a vaccine against malar ....Malaria infection of humans is one of the most important and deadly infectious diseases in the world, killing more than two million people each year. Traditionally, drugs and insecticides have been used to treat the disease and control its spread. Unfortunately, both of these have become much less effective and there now exist untreatable cases of malaria. Alternative control measures are urgently needed and this project focusses on the development of such an alternative, a vaccine against malaria using plants transgenic for genes encoding vaccine molecules. Growing these plants not only provides a potentially inexpensive vaccine production system but also offers a potential delivery system such that immunisation may be possible simply through consumption of an edible vaccine. This project intends to investigate the possibility of using transgenic plants expressing malaria antigens to induce protective immunity against malaria infection. The results of this project will provide vitally important information in malaria vaccine production and delivery.Read moreRead less
Identifying The Targets Of Protective Immunity To Malaria In Pregnancy
Funder
National Health and Medical Research Council
Funding Amount
$457,267.00
Summary
Malaria in pregnancy is a major cause of disease across many countries. Pregnant women have a high risk of malaria, and large numbers of malaria parasites accumulate in the placenta, which may lead to infant or maternal death. Malaria parasites infect the placenta by producing proteins that enable them to stick to the placenta. These malaria strains causing placental infection generally do not cause disease in non-pregnant individuals. Antibodies to the parasite proteins are produced in response ....Malaria in pregnancy is a major cause of disease across many countries. Pregnant women have a high risk of malaria, and large numbers of malaria parasites accumulate in the placenta, which may lead to infant or maternal death. Malaria parasites infect the placenta by producing proteins that enable them to stick to the placenta. These malaria strains causing placental infection generally do not cause disease in non-pregnant individuals. Antibodies to the parasite proteins are produced in response to placental infection, which may help control the infection and protect against further malaria in pregnancy. However, placental malaria parasites are able to vary the proteins they produce to avoid immune responses. In this project, we will study the parasite strains that cause malaria in pregnancy and the development of antibodies that protect pregnant women against malaria and its complications. We aim to identify the genes and proteins that parasites use to stick to the placenta, and determine how much variation occurs in these proteins. We will also specifically examine the role of one particular candidate gene called var2csa, and its protein, as this has been recently been associated with pregnancy malaria. We will examine how antibodies develop that recognise different proteins and different forms of malaria parasites, and determine the type of antibodies that protect pregnant women taking part in a longitudinal study of malaria in pregnancy in Malawi, Africa. We will also examine how antimalarial drugs taken in pregnancy influence the development of protective antibodies. Through these studies we aim to understand how the immune system combats malaria in pregnancy. This will be important for developing new methods for preventing or treating malaria in pregnancy, and improving child and maternal health.Read moreRead less
Severe Malaria In Children In Papua New Guinea: A Longitudinal Study Of Pathophysiology, Management And Outcome
Funder
National Health and Medical Research Council
Funding Amount
$484,808.00
Summary
The features of severe infection in children living in tropical countries may not allow differentiation between malaria and bacterial-viral causes. This can create significant problems with deciding on appropriate management. In addition, the main complications of malaria such as coma, increased acid levels in the blood and anaemia are not well understood. We plan to characterise infections in Papua New Guinean children in detail and explore mechanisms behind important malarial complications.