Seroprevalence of specific total immunoglobulin (Ig), IgG and IgM antibodies to Toxoplasma gondii in blood donors from Loei Province, Northeast Thailand.

A total samples from 345 healthy blood donors from Loei Province, Northeast Thailand were examined for anti-Toxoplasma gondii antibodies by ELISA. The seroprevalence of the anti-Toxoplasma gondii total Ig, IgG and IgM antibodies was 4.9%, 4.1% and 4.3%, respectively. Overall seropositive rate was 33 out of 345 individuals (9.6%). Among the seropositve cases, 5 (15.2%), 2 (6.1%) and 13 (39.4%) of the samples were determined by using each type of anti-T. gondii total Ig, IgG and IgM antibodies, respectively. The seropositive sera was also determined by combining of anti-T. gondii antibodies (anti-T. gondii total Ig with IgG and anti-T. gondii total Ig with IgM antibodies). These results were 10 (30.3%) and 2 (6.1%) cases, respectively. Only one (3%) sample had all types of anti-T. gondii antibodies. In addition, the frequency distribution curves of ELISA optical densities of anti-T. gondii total Ig, IgG and IgM antibodies in blood donor presented "unimodal" curves. The negative results were found in the age group that less than 20 years old and more than 51. The highest seropositive results were found in two age groups (21-30 and 31-40 years old), and males were significantly higher than female (p < 0.05). These results demonstrated that when using anti-T. gondii total Ig, IgG and IgM antibodies for determining the seroprevalence, the sensitivity was twice that with the anti-T. gondii, total Ig antibody alone.

Gnathostoma spinigerum: analysis of protein patterns by two dimensional gel electrophoresis.

The protein extracts from male (MS) and female (FS) adults and advanced third-stage larvae (LS) of Gnathostoma spinigerum were separated by high resolution two-dimensional gel electrophoresis (2-DE). The polypeptide spots, as detected by silver staining, were subsequently identified. The spot patterns of LS, MS and FS were highly complex and consisted of more than 75, 44, 52 prominent spots, respectively. In addition, the stage-specific protein patterns were identified. This 2-DE database should provide an important reference for future biological and biochemical studies of G. spinigerum.

Antigenic components of Gnathostoma spinigerum recognized by infected human sera by two-dimensional polyacrylamide gel electrophoresis and immunoblotting.

Antigenic components of Gnathostoma spinigerum larval extract were revealed by two-dimensional gel electrophoresis (2-DE) and immunoblot analysis using sera from patients with 6 proven cases of gnathostomiasis, 5 presumptive cases of gnathostomiasis, 3 proven cases of angiostrongyliasis, 3 proven cases of cysticercosis, and pooled sera from healthy adults. By the 2-DE, the larval extract was highly complex and consisted of more than 75 polypeptides. Immunoblotting analysis of this larval extract after reaction with each of 6 proven gnathostomiasis sera revealed various numbers of antigenic spots ranging from 30 to 70 spots at the approximate molecular masses of less than 14.4 to more than 94 kDa with isoelectric points (pI) of less than 4.65 to 9.6. Antigenic spots at the approximate molecular mass of more than 30 kDa were recognized with the proven angiostrongyliasis, proven cysticercosis and healthy control sera but these sera did not react with the spots at approximate molecular masses of 23-25 kDa with pI of 8.3-8.5. The reacted spots, which consisted of at least 1 to 2 spots, were unique for the recognition of gnathostomiasis sera. Five out of 6 (83.3%) proven and 4 out of 5 (80%) presumptive gnathostomiasis sera reacted with these specific spots.

Excretory-secretory antigenic components of adult Fasciola gigantica recognized by infected human sera.

The immunogenic components of Fasciola gigantica excretory-secretory (ES) products were revealed by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting technic using sera from patients with F. gigantica infection, from patients with clinical suspected fascioliasis, from patients with other illness and from healthy adults. By SDS-PAGE, it was found that the ES products comprised more than 6 polypeptides. Immunoblotting analysis revealed 12 components which were strongly recognized by fascioliasis antisera. These antigenic components had a molecular mass ranging from less than 14.4 to 38 kDa. One antigenic band of 27 kDa was found to give a consistent reaction with fascioliasis antisera (100% sensitivity and 98% specificity). The present findings suggest that the 27 kDa components are sensitive and specific for the diagnosis of human F. gigantica infection.

Specific monoclonal antibodies to Fasciola gigantica.

Monoclonal antibodies (mAbs) were produced against soluble metabolic products (excretory/secretory; ES) of the liver fluke, Fasciola gigantica. The ES antigen was obtained from spent culture medium in which the adult flukes had been maintained in vitro. From two cell fusions, the mAbs produces were exclusively associated with either IgG or IgM isotypes. When screened against a panel of homologous and heterologous parasite antigens by indirect ELISA, two mAbs were highly specific for F. gigantica. The remainder cross-reacted extensively with other parasites. Results from immunoblotting and immunofluorescence exhibited two patterns of reactivity. The first group of mAbs which recognized the multiple bands between > 14.4-27.5 kDa gave extremely bright fluorescence over all major muscular systems, vitelline gland, testes and intestinal caeca. The second group which reacted with the 185 kDa band showed a bright fluorescence over a thinner muscular layer underlying the tegument, intestinal caeca and testes.