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At least 19 recordsLinked to original sources
PubMed1994

Immunological neutralization of cobrotoxin by its homologous precipitin and non-precipitin antibodies.

Anti-cobrotoxin antibodies can be separated into precipitin and non-precipitin antibodies. The precipitin antibody possesses the same binding affinity to cobrotoxin as non-precipitin antibody, but the neutralizing capability of the latter is superior to that of the former in blocking cobrotoxin binding to nicotinic acetylcholine receptor (nAChR). After preincubation with antibodies, cobrotoxin completely lost its binding activity to nAChR. The dissociation of cobrotoxin-nAChR complex by the antibodies was low, and 60% of the complex formation appeared to be irreversible. These results indicate that the neutralization of cobrotoxin by the antibody may predominantly involve unbound, receptor-free cobrotoxin. The relationships of neutralization capacity and binding affinity as well as bond strength between cobrotoxin and its antibodies are incongruous. Different local conformational changes of a unique Trp in cobrotoxin on binding with the precipitin and non-precipitin antibodies seem to lead to different accessibility for fluorescence quenchers. Characterization of the binding domains by immunoprecipitation with the antibodies correlated with the quenching results. Thus, the binding topography of cobrotoxin may play an important role over the binding affinity and bond strength in neutralization by cobrotoxin antibody.

Animals↗
PubMed1967

Agar-gel precipitin-inhibition test for coccidioidomycosis. I. Preliminary evaluation of the complement-fixation and agar-gel precipitin tests in the serodiagnosis of human coccidioidomycosis.

The agar-gel precipitin-inhibition serological test for coccidioidomycosis was a more sensitive indicator of Coccidioides immitis antibodies than the tube precipitin, the agar-gel immunodiffusion, in the complement-fixation tests in assaying monkey sera, whether these sera were from prechallenge-vaccinated or postchallenged animals. When applying this technique to the assay of human sera, an analogous finding generally persisted. However, some human sera were positive by the complement-fixation test and negative by the agar-gel precipitin-inhibition test. These sera were diffused in agar-gel against various coccidioidin complement-fixation, tube precipitin, and agar-gel precipitin-inhibition test antigens with essentially negative results.

Animals↗
PubMed1989

Immunoaffinity isolation and partial characterization of the Coccidioides immitis antigen detected by the tube precipitin and immunodiffusion-tube precipitin tests.

The antigen participating in the tube precipitin (TP) serologic test for coccidioidomycosis was isolated from mycelial-phase antigen (coccidioidin) by immunoaffinity and characterized by various analytical procedures. This was accomplished by first preparing the antigen-antibody precipitate by using antigen and human serum positive for TP (immunoglobulin M) antibody and then liberating the antigen by digestion with pronase. This protease destroyed the antibody and left the antigen intact as indicated by immunodiffusion-TP. The coccidioidal antigen was isolated from the proteolytic digest by using size exclusion chromatography. DEAE chromatography of this antigen yielded two fractions with immunodiffusion-TP reactivity which had average molecular sizes of 225 and 140 kilodaltons, respectively. The presence of carbohydrate and amino acids indicated that the antigen(s) is a glycopeptide. Compositional analysis showed that one fraction contained 3-O-methylmannose, mannose, and glucose in a ratio of 8:1.2:1, whereas the second fraction contained 3-O-methylmannose, mannose, glucose, and galactose in a ratio of 1:1:1:1. The amino acids glycine, alanine, serine, threonine, aspartic acid plus asparagine, and glutamic acid plus glutamine constituted 60 to 70% of the amino acids in both glycopeptides. Neither antigen could be detected entering the gel in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Lectin affinity provided evidence of a high-mannose asparagine-linked glycopeptide in the first peak and an asparagine-linked glycopeptide with a biantennary complex-type structure in the second peak.

Amino Acids↗
PubMed1980

Circumoval precipitin antigens for the diagnosis of schistosomiasis. I. Development of an antiserum reactive with Schistosoma mansoni eggs by the circumoval precipitin test.

A serum was developed which reacts with Schistosoma mansoni eggs by the circumoval precipitin (COP) test. This antiserum to COP antigens was prepared by coupling the COP immune complexes to protein A-Sepharose, isolating the complex with acid buffer, and immunizing rabbits with the eluate. The antiserum reacted with S. mansoni eggs, forming globular bleb and septate precipitates. It also reacted in gel diffusion with a soluble egg antigen preparation of S. mansoni (SEA). Of four SEA antigenic components precipitated one was clearly MSA1. The antiserum to the COP antigens had anti-parasite antibodies absorbable with lyophilized cercariae or eggs. Three human immunoglobulins (IgG, IgM, and IgA) were involved in the COP reaction.

Animals↗
PubMed1989

[Comparison of immunoenzymatic staining technique (IEST), double gluing strip circumoval precipitin test (DGS-COPT) and conventional circumoval precipitin test (CV-COPT) for diagnosis of schistosomiasis japonica].

IEST, DGS-COPT and CV-COPT using lyophilized ova of schistosoma japonicum were performed on sera from 120 cases of schistosomiasis japonica, 120 cases of schistosomiasis japonica 3-8 years after being cured with praziquantel and 120 healthy individuals by single-blind method. The sensitivity and specificity of IEST was 91.7% and 95.8% respectively which were significantly higher than that of both DGS-COPT and CV-COPT. The negative conversion rate of cured patients was 70.8% with IEST, 80.8% with DGS-COPT and 81.7% with CV-COPT. The results showed that IEST has higher diagnostic value for schistosomiasis than both COPT. DGS-COPT has the same diagnostic value as CV-COPT, however, it was easy to perform and time-saving, thus it might be applied in the fields for practical purposes.

Animals↗