After completing a PhD (Biochemistry) at Monash University in 1977, I undertook postdoctoral studies at Mahidol University (Thailand), Colorado State University and UCLA (1977-1981).
Since 1981, I have held positions as a Research Scientist at Walter and Eliza Hall Institute, Head of Department at Victorian Institute of Animal Science, Associate Professor in Biochemistry and Molecular Biology at Monash before joining McGill University (Canada) in 2001 as Director of the Institute of Parasitology where I held a prestigious Canada Research Chair in Immunoparasitology (2002-7).
In 2007, I was appointed Strategic Research Professor in the School of Animal and Veterinary Sciences at CSU, where I will continue my work discovering molecular knowledge of parasite functions in order to develop vaccines or drugs to control infection. My specific research interests include the molecular biology and protein biochemistry of eukaryote parasites and the development of diagnostic tools using biomarker approaches.
Current PhD and postdoc projects in the lab
I have several PhD projects available for study that offer the opportunity to perform cutting edge research using the techniques of immunology, molecular biology and protein chemistry. Students who would be competitive to obtain student scholarships, have an interest in studying medical or veterinary diseases and would like to acquire training in modern molecular techniques in a stimulating environment are encouraged to contact me by email email@example.com or tel 02-6933 2439.
We are studying the host and parasite factors underpinning immunity to fasciolosis using several approaches:
- using proteomics to analyse host plasma and macrophage biomarkers associated with expression of immunity within 6 weeks of infection in cattle;
- using monocyte/ macrophages and sera from cattle vaccinated by a drug-abbreviated infection to define the cells, IgG isotype and effector molecules in cattle that are involved in ADCC killing of F. hepatica NEJ in vitro.
- using proteomics to analyse surface-exposed juvenile parasite proteins that are potential targets of this immunity.
Project 1: Identify biomarkers associated with expression of acquired immunity in cattle.
Cattle express acquired resistance early after drug-abbreviated infections and killing of flukes occurs within 6 weeks of challenge during the parenchymal phase of infection. We will focus on the time window from 1-6 weeks after infection and carefully examine biomarkers in plasma and activated monocyte/ macrophages (recovered from donor cattle) of treated vs non treated cattle. This study will document for the first time the induction of key plasma/macrophage proteins associated with acquired immunity against F. hepatica in cattle and allow us to form new hypotheses about effector pathways operating in cattle.
Project 2: Linking in vivo and in vitro approaches by defining bovine immune effector mechanisms that kill F. hepatica in vitro
We will use monocyte/macrophages and sera from cattle vaccinated by a drug-abbreviated infection to define the cells, IgG isotype and effector molecules in cattle that are involved in ADCC killing of F. hepatica NEJ using our in vitro assay system. The effector molecule(s) active in cattle is unknown but will be defined using specific inhibitors in the killing assay (eg. SOD, NMMA) to assess the relative levels of ROS and NO produced under our assay conditions. Monocyte/macrophages will be incubated with/without the different antibody fractions and killing of NEJ of F. hepatica will be estimated.
Project 3: Identify and characterize surface-exposed tegument proteins expressed in F hepatica and recognised by sera from vaccinated cattle
Postdoctoral fellow: Dr Janelle Wright
We are starting to define tegument proteins expressed on adult parasites using several biochemical approaches. We will use the tegument biotinylation technique to purify and identify tegument proteins on adult and juvenile parasites using proteomic approaches. We will first establish the technique with adult flukes and then explore the juvenile tegument. Surface-biotinylated proteins will be enriched using streptavidin, the proteins separated by one or 2D gel electrophoresis, protein bands/spots eluted and digested with trypsin. Protein identities will be obtained either by peptide mass fingerprinting and matching to existing EST databases for F. hepatica or by direct MS/MS analysis to generate amino acid sequences.
Only a subset of these proteins will be targets for ADCC against F hepatica. We will perform western blot analyses to determine which of the surface tegument proteins, enriched by streptavidin binding, are also targets of IgG1 or IgG2 responses in immune cattle. By focussing only on those proteins that are selectively enriched by biotinylation-streptavidin isolation, we will determine those proteins that are surface exposed and antigenic in cattle during the time window (weeks 1-6 post challenge) when acquired immunity is expressed.
My recent research has focused on the parasites Fasciola (liver fluke) and Plasmodium (malaria) studying areas such as host immune responses to parasites, parasite immune evasion mechanisms, parasite proteomics and vaccine and drug discovery. We are characterising parasite molecules that determine virulence and pathogenesis using genomic/proteomic approaches with the long term aim of developing vaccines based on these molecules.
I also have an interest in biomarkers of disease and developing new diagnostics based on these biomarkers. One new project in my lab aims to look at biomarkers of mastitis in milk (see below). We are also interested in evaluating new drugs as potential chemotherapies for F. hepatica. We recently showed that DNA binding drugs are highly effective anti-malarials ( see Yanow et al, 2008) and we are interested to determine if such drugs are active against other parasites.
I am looking for highly motivated graduate students and postdoctoral fellows to tackle the challenges caused by these diseases. My research has a deliberate international outlook with current collaborations in Sudan, Thailand, China, India, UK, Canada and Australia.
Liver fluke disease and vaccine development
Liver fluke infection (fasciolosis) is a major neglected zoonotic disease caused by Fasciola hepatica and F. gigantica, flatworm parasites transmitted following ingestion of infective metacercariae encysted on aquatic plants. Liver flukes are a serious constraint on global livestock production, with >600m animals at risk of fasciolosis and economic losses of >US$3b p.a. (see Piedrafita et al, 2004). In Australia, economic losses are $60-90m p.a, with tens of millions of sheep/cattle exposed to the infection. Fasciola is also a significant food borne zoonosis recognised by the WHO and human cases of fasciolosis have been reported in Australia including work from my laboratory (Hughes et al 2003). There is no commercial vaccine for this disease. My lab is examining acquired immune mechanisms expressed by sheep and cattle that are involved in killing juvenile liver flukes with a view to vaccine development.
Current experimental fluke vaccines, including work from my lab, can only achieve partial protection, manifested by reductions in fluke burdens of 38-72% in cattle. Although some vaccinates show >90% reduction in fluke burdens, a major constraint for vaccine design is the fact that we do not know which effector mechanisms in cattle actually control infections (ie kill the parasite) or why some animals respond better than others. This hinders our ability to lift vaccine efficacy to commercially desirable levels.
Multiple published studies provide strong evidence that cattle can acquire high levels of resistance (80-98%) to Fasciola following vaccination using irradiated metacercariae, drug abbreviated infection, parasite extracts or defined antigens (reviewed in Piedrafita et al 2004). These observations show that Fasciola antigens can induce protective immune responses in cattle and that a defined commercial vaccine that achieves >80% protection is a theoretically achievable goal if we can better understand how the immune system controls fluke infections.
Data from different studies in cattle and sheep showed that immune killing of parasites occurs within 6 weeks of infection but only after some damage occurs to the liver parenchyma, suggesting that the newly excysted or immature juvenile (NEJ) parasite, not the adult parasite, is the primary target of the effective immune response in the liver. However, we do not know which effector mechanisms kill liver flukes within 6 weeks of infection or the parasite antigens that are the target of this response.
We were the first to show that Fasciola NEJ are susceptible to antibody-dependent cell cytotoxicity (ADCC) mediated by superoxide radicals produced by sheep macrophages in vitro (Piedrafita et al 2007). Our results suggest two important conclusions;
- that macrophages, acting in concert with specific antibody, are critical effector cells involved in the resistance to liver fluke but we need to know more about how the host activates macrophages and kill flukes
- that antigens on the surface of juvenile/immature flukes, recognised by immune sera, are the targets of the ADCC mechanism and we need to know more about these antigens.
Recent publications last 5 years
A complete list of my publications can be found on the PubMed web site at http://www.ncbi.nlm.nih.gov/sites/entrez
- Irving, J., SPITHILL,T.W., Pike, R.N., Whisstock, J.C. and P. M. Smooker. The evolution of enzyme specificity in Fasciola spp. J Mol Evolution 57:1-15 (2003).
- Hughes, A.J., SPITHILL, T.W., Smith , R.E., Boutlis, C. and Johnson, P.D.R. Human fasciolosis acquired in an Australian urban setting. Med J Aust 178:244-5 (2003).
- Rainczuk, A, Smooker, P.M, Kedzierski, L., Black, C.G, Coppel, R.L, and SPITHILL, T.W. The protective efficacy of MSP4/5 against lethal P.chabaudi adami challenge is dependent on the type of DNA vaccine vector type and vaccination protocol. Vaccine 21: 3030-42. (2003).
- Rainczuk, A., Scorza, T., Smooker, P.M, and SPITHILL, T.W. Induction of Specific T-cell responses, opsonizing antibodies, and protection against Plasmodium chabaudi adami infection in mice vaccinated with genomic expression libraries expressed in targeted and secretory DNA vectors. Inf Immun 71:4506-4515 (2003).
- Boag P.R., Parsons, J.C., Presidente, P..J, SPITHILL, T.W. and Sexton, J,L. Characterisation of humoral immune responses in dogs vaccinated with irradiated Ancylostoma caninum. Vet Immunol Immunopathol. 92: 87-94 (2003).
- Law, R.H.P., Smooker, P.M., Irving, J.A., Piedrafita, D., Ponting, R., Kennedy, N.J., Whisstock, , J.C., Pike, R.N. and SPITHILL, T.W. Cloning and expression of the major secreted cathepsin B-like protein from juvenile Fasciola hepatica and analysis of immunogenicity following liver fluke infection. Inf Immun 71:6921-32 (2003).
- Piedrafita, D., Raadsma, H., Prowse, R. and SPITHILL, T.W. Immunology of the Host Parasite Relationship in Fasciolosis (Fasciola hepatica and Fasciola gigantica). Invited Review. Can J Zoology 82: 233-250 (2004).
- Smooker, P.M., Rainczuk, A., Kennedy, N. and SPITHILL, T.W. DNA vaccines and their application against parasites: promise, limitations and potential solutions. Biotechnology Annual Reviews 10: 189-236 (2004).
- Rainczuk, A., Scorza, T., SPITHILL, T.W. and Smooker, P.M. A bicistronic DNA vaccine containing Apical Membrane Antigen-1 and Merozoite Surface Protein 4/5 can prime humoral and cellular immune responses and partially protect mice against virulent P. chabaudi adami DS malaria. Inf Immun 72: 5565-5573 (2004).
- Scorza, T., Grubb, K., Smooker,P., Rainczuk , A., Proll, D. and SPITHILL, T.W. Induction of strain-transcending immunity against Plasmodium chabaudi adami malaria with a multiepitope DNA vaccine. Inf Immun 73: 2974-2985 (2005).
- Kennedy, N.J., SPITHILL, T.W., Tennent, J., Wood, P.R. and D. Piedrafita. DNA vaccines in sheep: CTLA-4 targeting and CpG motifs enhance immunogenicity in a DNA prime/protein boost strategy. Vaccine 24: 970-979 (2006).
- SPITHILL, T.W. Crystal Ball issue: Engineering transgenic P falciparum to propagate in mice. Parasite Immunol. 28: 235-269 (2006).
- Yanow, S.K., Purcell, L.A. and SPITHILL, T.W. The A/T-specific DNA alkylating agent Adozelesin inhibits P. falciparum growth in vitro and protects mice against P. chabaudi infection. Mol Biochem Parasitol. 148: 52-59 (2006).
- Beckham, S.A., Law, R.H., Smooker,P.M., Quinsey, N.S., Caffrey, C.R., McKerrow, J.H., Pike, R.N. and T.W. SPITHILL. Production and processing of a recombinant Fasciola hepatica cathepsin B-like enzyme (FhcatB1) reveals potential processing mechanisms in the parasite. Biol. Chem 38: 1053-1061. (2006)
- Boscariol, R., Pleasance, J., Piedrafita, D.M., Raadsma, H.W. and SPITHILL, T.W. Sequence of cDNAs for two allelic forms of ovine CD4 predicts a Ser183/Pro183 polymorphism in the coding sequence of domain 3. Vet Immunol Immunopathol 113: 305-312 ( 2006)
- Raadsma, H.W., Kingsford, N.M., Suharyanta, SPITHILL, T.W. and Piedrafita. D. Host responses during experimental infection with Fasciola gigantica or Fasciola hepatica in Merino sheep I. Comparative immunological and plasma biochemical changes during early infection. Vet Parasitol. 143: 275-286 (2007).
- Piedrafita,D.M., Estuningsih, E., Pleasance, J., Prowse, R.K., Raadsma,H.W., Meeusen, E.N.T. and T.W. SPITHILL. Peritoneal lavage cells of Indonesian thin tail sheep mediate antibody-dependent superoxide radical cytotoxicity in vitro against newly excysted juvenile Fasciola gigantica but not juvenile Fasciola hepatica. Inf. Immunity 75:1954-1963. (2007).
- Yanow, S.K., Purcell, L.A., Lee, M., Spithill, T.W. Genomics-based drug design targets the AT-rich malaria parasite: implications for anti-parasite chemotherapy. Pharmacogenomics 8: 1267-1272 (2007).
- Rioux, M.C., Carmona, C., Acosta, D., Ward, B., Ndao, M. and T.W. SPITHILL. Discovery and validation of serum biomarkers over the first twelve weeks of Fasciola hepatica infection in sheep. (invited paper) Int J Parasitol. 38:123-36 (2008)
- Yanow, S.K*., Purcell, L.A*., Pradel, G., Sato, A., Rodriguez, A., Lee, M., Spithill, T.W. Potent antimalarial and transmission-blocking activities of a novel DNA binding agent. J Inf Diseases 197:527???534 (2008).* joint first author.
- Scorza, T., Grubb, K., Cambos,M., Santamaria, C., Tshikudi Malu, D. and T. W. SPITHILL. Vaccination with a Plasmodium chabaudi adami multivalent DNA vaccine cross protects A/J mice against challenge with P c adami DK and virulent P. c. chabaudi AS parasites. Int J Parasitol 38: 819-827 ( 2008).
- McGonigle, L., Mousley, A., Marks, N.J., Brennan, G.P., Dalton, J.P., SPITHILL, T.W., Maule, A.G. The silencing of cysteine proteases in Fasciola hepatica newly excysted juveniles using RNA interference. Int J Parasitol 38:149-155 (2008).
- Smith, R.E., SPITHILL, T.W., Pike, R.N., Meeusen, E.N.T., D. Piedrafita. Fasciola hepatica and Fasciola gigantica: Cloning and characterisation of 70kDa heat-shock proteins reveals variation in HSP70 gene expression between parasite species recovered from sheep. Exp Parasitology 118:536-542 ( 2008).
- Purcell, L.A., Yanow, S.K., Lee, M., SPITHILL,T.W. and Rodriguez, A. Chemical attenuation of Plasmodium berghei sporozoites induces sterile immunity in mice. Inf Immunity 76:1193-9 (2008).
- Raadsma H. W., Kingsford N.M, Suharyanta, SPITHILL, T.W and Piedrafita D. Host responses during experimental infection with Fasciola gigantica and Fasciola hepatica in Merino sheep: II Development of a predictive index for Fasciola gigantica worm burden. Vet Parasitology 154: 250-61 (2008).
- Purcell, L.A., Wong, K.A., Yanow, S.K., Lee,M., SPITHILL, T.W. and A. Rodriguez. Chemically attenuated Plasmodium sporozoites induce specific immune responses, sterile immunity and cross-protection against heterologous challenge. Vaccine 26:4880-4884 (2008).
- Estuningsih, S.E., SPITHILL, T.W., Raadsma H.W., Law, R.H.P., Adiwinata, G., Meeusen, E., and Piedrafita, D. Development and application of a faecal diagnostic sandwich ELISA for estimating prevalence of Fasciola gigantica in cattle in central Java, Indonesia. J. Parasitology (in press 2008).
Recent graduates from my lab - Where are they know?
2007. Lisa Purcell, Institute of Parasitology, McGill. PhD Thesis: "Genetic and biochemical strategies to block the transmission cycle of the malaria parasite". Now a postdoctoral fellow at Regeneron, New York. http://www.regeneron.com/
2006. Rebecca Smith, Department of Biochemistry and Molecular Biology, Monash University. PhD Thesis: " Cloning and characterisation of pathogenesis factors of Fasciola hepatica using cDNA representational difference analysis and signal sequence trap approaches" . Now a postdoctoral fellow at Univ. Melbourne.
2005. Simone Beckham, Department of Biochemistry and Molecular Biology, Monash University. PhD Thesis: " Characterisation of cathepsin proteases from Fasciola hepatica". Now a postdoctoral fellow at Monash.
2005. Nick Kennedy, Department of Biochemistry and Molecular Biology, Monash University. PhD Thesis: "DNA vaccines for Fasciola hepatica". Now a postodoctoral fellow at Monash.
2005: Kim Grubb, Institute of Parasitology, McGill. MSc Thesis: "Malaria vaccine antigens". Now in the business sector in Montreal.
2005: Cynthia Santamaria, Institute of Parasitology, McGill. MSc Thesis: "Merozoite surface proteins in malaria". Now in research assistant at the McGill University Health Centre, Montreal.
2004. Adam Rainczuk, Department of Biochemistry and Molecular Biology, Monash University. PhD Thesis: "Evaluation of expression library immunisation as a tool for malaria vaccine discovery". Now Witchery Research Fellow at Prince Henry's Institute for Medical Research, Melbourne.
2004: Rya Boscariol, Institute of Parasitology, McGill. MSc Thesis: "Functional characterisation of Sheep CD4 and susceptibility to cleavage by Fasciola proteases". Now studying medicine at Queen's University, Ontario.