High polymorphism in genes encoding antigen B from human infecting strains of Echinococcus granulosus.
Echinococcus granulosus antigen B (AgB) is encoded by a gene family and is involved in the evasion of the host immune response. E. granulosus exists as a number of strains (G1-G10) that differ in biological characteristics. We used PCR-SSCP followed by DNA sequencing to evaluate sequence variation and transcription profile of AgB in 5 E. granulosus strains. Twenty-four genomic sequences were isolated and clustered in 3 groups related to 2 of the 5 reported AgB genes. AgB4 genes were present in almost all strains, whereas AgB2 were present as functional genes exclusively in G1/G2 cluster, and as non-functional genes in G5 and the G6/G7 cluster, suggesting inter-strain variation. The AgB transcription patterns, analysed by RT-PCR, showed that AgB2 and AgB4 genes were transcribed in G1, while only the AgB4 gene was transcribed in G7 strain. Cysts from the same strain or cluster shared more genomic and cDNA variants than cysts from different strain or cluster. The level of nucleotide and deduced amino acid sequence variation observed is higher than that reported so far for coding genes of other helminths. Neutrality was rejected for AgB2 genes. These data show the genetic polymorphism of antigen-coding genes among genetically characterized strains of E. granulosus.
Kamenetzky
L
L
Departamento de Parasitología, Instituto Nacional de Enfermedades Infecciosas ANLIS Av. Velez Sarsfield 563, Buenos Aires (1281), ArgentinaInstituto Tecnológico de Chascomús (IIB-INTECH)-Conicet/UNSAM, Chascomús, Argentina.
Muzulin
P M
PM
Gutierrez
A M
AM
Angel
S O
SO
Zaha
A
A
Guarnera
E A
EA
Rosenzvit
M C
MC
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002162:Camelus; D002417:Cattle; D048209:Echinococcus granulosus / Q000235:genetics* / Q000276:immunology; D020869:Gene Expression Profiling / Q000379:methods; D018503:Genome, Protozoan / Q000235:genetics*; D015801:Helminth Proteins / Q000737:chemistry / Q000235:genetics*; D006801:Humans; D008074:Lipoproteins / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000379:methods; D011110:Polymorphism, Genetic / Q000235:genetics*; D018807:Polymorphism, Single-Stranded Conformational; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D012756:Sheep; D013552:Swine
D015801:Helminth Proteins; D008074:Lipoproteins; C089273:antigen B, Echinococcus