A novel cDNA clone encoding a specific excretory/secretory antigen of larval Trichinella pseudospiralis.
A cDNA library for Trichinella pseudospiralis was constructed to study the expression of specific antigens. Four positive clones were identified using antibodies against the excretory/secretory (ES) products of the nematode as probe. Sequence analysis showed that they contained identical cDNA inserts of 606 bp, including a 5' non-translated region of 96 bp, a core translated segment of 408 bp and a poly(A)+ 3' terminus. It encoded a novel 136-amino-acid polypeptide. Southern blot analysis indicated that the cDNA did not cross-hybridize to the genomic digests of T. spiralis, mouse, or rat. A single copy only of its complementary sequence was found in the genome of T. pseudospiralis. Using the lambda ZAP expression system, the cDNA was induced to express a 23-kDa beta-galactosidase-fusion protein which did not cross-react with polyclonal and monoclonal antibodies against T. spiralis, heat shock proteins, or four heterologous species of nematodes. The antiserum against the fusion protein recognized a 15-kDa band from the ES products of T. pseudospiralis in immunoblotting. Immunocytolocalization demonstrated that the anti-fusion protein serum only recognized an epitope in the stichosome of T. pseudospiralis and not in T. spiralis. The protein can therefore serve as a specific antigen for the differential diagnosis of trichinellosis.
Chung
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Department of Zoology, The University of Hong Kong, China.
Ko
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RC
D000595:Amino Acid Sequence; D000818:Animals; D000947:Antigens, Helminth / Q000235:genetics*; D001483:Base Sequence; D015139:Blotting, Southern; D003001:Cloning, Molecular; D018509:DNA, Helminth; D015723:Gene Library; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D008969:Molecular Sequence Data; D011817:Rabbits; D051381:Rats; D017208:Rats, Wistar; D017422:Sequence Analysis, DNA; D013552:Swine; D014234:Trichinella / Q000235:genetics* / Q000276:immunology
D000947:Antigens, Helminth; D018509:DNA, Helminth