Paramyosin is a myofibrillar protein present in helminth parasites and plays multifunctional roles in host-parasite interactions. In this study, we identified the gene encoding paramyosin of Clonorchis sinensis (CsPmy) and characterized biochemical and immunological properties of its recombinant protein. CsPmy showed a high level of sequence identity with paramyosin from other helminth parasites. Recombinant CsPmy (rCsPmy) expressed in bacteria had an approximate molecular weight of 100 kDa and bound both human collagen and complement 9. The protein was constitutively expressed in various developmental stages of the parasite. Imunofluorescence analysis revealed that CsPmy was mainly localized in the tegument, subtegumental muscles, and the muscle layer surrounding the intestine of the parasite. The rCsPmy showed high levels of positive reactions (74.6%, 56/75) against sera from patients with clonorchiasis. Immunization of experimental rats with rCsPmy evoked high levels of IgG production. These results collectively suggest that CsPmy is a multifunctional protein that not only contributes to the muscle layer structure but also to non-muscular functions in host-parasite interactions. Successful induction of host IgG production also suggests that CsPmy can be applied as a diagnostic antigen and/or vaccine candidate for clonorchiasis.
Amino Acid Sequence ; Animal Structures/chemistry ; Animals ; Antibodies, Helminth/blood ; Cloning, Molecular ; Clonorchis sinensis/chemistry/*genetics ; Collagen/metabolism ; Complement C9/metabolism ; Helminth Proteins/chemistry/*genetics/immunology/metabolism ; Immunoglobulin G/blood ; Molecular Sequence Data ; Molecular Weight ; Protein Binding ; Rats ; Rats, Sprague-Dawley ; Sequence Alignment ; Sequence Analysis, DNA ; Sequence Homology, Amino Acid ; Tropomyosin/chemistry/*genetics/immunology/metabolism

Meningococcal disease is not rarely associated with abnormalities of the complement system. We experienced a case of C9 deficiency with meningococcal meningitis from a 12-year-old girl. Identification of complement deficiency has implications for management, including family studies, prophylaxis, vaccination, and altered threshold for infection screening and treatment.
Child ; Complement C9* ; Complement System Proteins* ; Female ; Humans ; Mass Screening ; Meningitis ; Meningitis, Meningococcal* ; Neisseria meningitidis ; Vaccination

BACKGROUND: Molecular and genetic studies of the complement component C9 have never been reported in Korea. METHODS: We have checked the TaqI polymorphism of the C9 gene in 52 randomly selected adult Koreans. Southern blot analysis was carried out to detect the restriction fragment length polymorphism (RFLP) of the C9 gene. The fragments of human C9 cDNA were hybridized with the TaqI digested genomic DNA. RESULTS: The functional levels of complements in all subjects were measured at 84.4+/-3.8% by hemolytic assay, which indicates that the subjects have functionally normal complement systems. Fifty-four percent of the individuals were found to have the C9 genes that contain the constant fragments only. It seems that the undetected TaqI site may be located in the intron of the C9 gene. The silent mutation of C->T transversion was found in exon 1 of the C9 gene through polymerase chain reaction-single strand conformational polymorphism, but no mutation was found in exon 4 of the C9 gene. CONCLUSIONS: We could not find TaqI polymorphism in exons of the C9 gene in 52 Koreans.
Adult ; Blotting, Southern ; Complement C9 ; Complement System Proteins* ; DNA ; DNA, Complementary ; Exons* ; Humans ; Introns ; Korea ; Polymorphism, Restriction Fragment Length