Preliminary molecular characterization of the human pathogen Angiostrongylus cantonensis.
BACKGROUND
Human angiostrongyliasis is an emerging food-borne public health problem, with the number of cases increasing worldwide, especially in mainland China. Angiostrongylus cantonensis is the causative agent of this severe disease. However, little is known about the genetics and basic biology of A. cantonensis.


RESULTS
A cDNA library of A. cantonensis fourth-stage larvae was constructed, and approximately 1,200 clones were sequenced. Bioinformatic analyses revealed 378 cDNA clusters, 54.2% of which matched known genes at a cutoff expectation value of 10(-20). Of these 378 unique cDNAs, 168 contained open reading frames encoding proteins containing an average of 238 amino acids. Characterization of the functions of these encoded proteins by Gene Ontology analysis showed enrichment in proteins with binding and catalytic activity. The observed pattern of enzymes involved in protein metabolism, lipid metabolism and glycolysis may reflect the central nervous system habitat of this pathogen. Four proteins were tested for their immunogenicity using enzyme-linked immunosorbent assays and histopathological examinations. The specificity of each of the four proteins was superior to that of crude somatic and excretory/secretory antigens of larvae, although their sensitivity was relatively low. We further showed that mice immunized with recombinant cystatin, a product of one of the four cDNA candidate genes, were partially protected from A. cantonensis infection.


CONCLUSIONS
The data presented here substantially expand the available genetic information about the human pathogen A. cantonensis, and should be a significant resource for angiostrongyliasis researchers. As such, this work serves as a starting point for molecular approaches for diagnosing and controlling human angiostrongyliasis.
Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, 74 Zhongshan, 2nd Road, Guangzhou, 510080, PR China. hehual@mail2.sysu.edu.cn
Hualiang
H
He
Mei
M
Cheng
Xiao
X
Yang
Jinxiu
J
Meng
Ai
A
He
Xiaoying
X
Zheng
Zhuoya
Z
Li
Pengjuan
P
Guo
Zhihua
Z
Pan
Ximei
X
Zhan
D000595:Amino Acid Sequence; D017185:Angiostrongylus cantonensis / Q000235:genetics* / Q000276:immunology*; D000818:Animals; D000947:Antigens, Helminth / Q000737:chemistry / Q000276:immunology; D001483:Base Sequence; D055162:Biocatalysis; D001921:Brain / Q000469:parasitology / Q000473:pathology; D018076:DNA, Complementary / Q000235:genetics; D006801:Humans; D007814:Larva / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000737:chemistry / Q000276:immunology; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D017206:Strongylida Infections / Q000276:immunology / Q000469:parasitology; D014612:Vaccines / Q000276:immunology
D000947:Antigens, Helminth; D018076:DNA, Complementary; D011994:Recombinant Proteins; D014612:Vaccines