title: From genomes to vaccines: Leishmania as a model.
abstract: The 35 Mb genome of Leishmania should be sequenced by late 2002. It contains approximately 8500 genes that will probably translate into more than 10 000 proteins. In the laboratory we have been piloting strategies to try to harness the power of the genome-proteome for rapid screening of new vaccine candidate. To this end, microarray analysis of 1094 unique genes identified using an EST analysis of 2091 cDNA clones from spliced leader libraries prepared from different developmental stages of Leishmania has been employed. The plan was to identify amastigote-expressed genes that could be used in high-throughput DNA-vaccine screens to identify potential new vaccine candidates. Despite the lack of transcriptional regulation that polycistronic transcription in Leishmania dictates, the data provide evidence for a high level of post-transcriptional regulation of RNA abundance during the developmental cycle of promastigotes in culture and in lesion-derived amastigotes of Leishmania major. This has provided 147 candidates from the 1094 unique genes that are specifically upregulated in amastigotes and are being used in vaccine studies. Using DNA vaccination, it was demonstrated that pooling strategies can work to identify protective vaccines, but it was found that some potentially protective antigens are masked by other disease-exacerbatory antigens in the pool. A total of 100 new vaccine candidates are currently being tested separately and in pools to extend this analysis, and to facilitate retrospective bioinformatic analysis to develop predictive algorithms for sequences that constitute potentially protective antigens. We are also working with other members of the Leishmania Genome Network to determine whether RNA expression determined by microarray analyses parallels expression at the protein level. We believe we are making good progress in developing strategies that will allow rapid translation of the sequence of Leishmania into potential interventions for disease control in humans.
authors.affiliation: Cambridge Institute for Medical Research, University of Cambridge School of Clinical Medicine, Wellcome Trust/MRC Building, Addenbrooke's Hospital, Hills Road, Cambridge CB2 2XY.
authors.forename: Renata
authors.initials: R
authors.lastname: Almeida
authors.forename: Alan
authors.initials: A
authors.lastname: Norrish
authors.forename: Mark
authors.initials: M
authors.lastname: Levick
authors.forename: David
authors.initials: D
authors.lastname: Vetrie
authors.forename: Tom
authors.initials: T
authors.lastname: Freeman
authors.forename: Jaak
authors.initials: J
authors.lastname: Vilo
authors.forename: Alasdair
authors.initials: A
authors.lastname: Ivens
authors.forename: Uta
authors.initials: U
authors.lastname: Lange
authors.forename: Carmel
authors.initials: C
authors.lastname: Stober
authors.forename: Sharon
authors.initials: S
authors.lastname: McCann
authors.forename: Jenefer M
authors.initials: JM
authors.lastname: Blackwell
mesh_terms: D000818:Animals; D020869:Gene Expression Profiling; D017125:Genes, Protozoan / Q000235:genetics; D018503:Genome, Protozoan; D006801:Humans; D007891:Leishmania / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D020543:Proteome / Q000235:genetics; D015800:Protozoan Proteins / Q000235:genetics; D016052:Protozoan Vaccines / Q000235:genetics*; D019444:Vaccines, DNA / Q000235:genetics
chemical_list: D020543:Proteome; D015800:Protozoan Proteins; D016052:Protozoan Vaccines; D019444:Vaccines, DNA