[Purification and specific detection of two major Schistosoma gut-associated circulating antigens, CAA and CCA].
OBJECTIVE
To investigate the specificity differences of the 2 major gut-associated diagnostic circulating molecules in Schistosoma japonicum infection, CAA and CCA, and to obtain sufficient purified material for setting up a standard series in quantitative determinations.


METHODS
Isolation and purification of the two worm fractions from a trichloroacetic acid (TCA) soluble preparation of S. japonicum adult worm antigen (AWAj-TCA) by Mono-Q anion exchange chromatography were performed and the specific reactivity of the eluted fractions by antigen-capture ELISA (specific for CAA or CCA) with reference to affinity purified preparations of S. mansoni CAA and CCA was analysed.


RESULTS
By using an ionic strength gradient, CCA was eluted in two major peaks, an unbound fraction CCA-1, and a major bound fraction CCA-2. Two additional minor peaks, CCA-3 and CCA-4, were eluted at higher ionic strengths. CAA was only detected in a bound fraction, partly overlapping with CCA-3. In the CCA-1 and CCA-2 fractions reactivity was only found in the antigen-capture ELISA using anti-CCA McAbs both for capture and detection. The CAA fraction was predominantly found to be positive in the antigen-capture ELISA using anti-CAA McAbs both for capture and detection. However, when using combinations of anti-CCA and anti-CAA McAbs for capture and detection by ELISA this fraction showed some reactivity.


CONCLUSIONS
Two CCA fractions contain molecules which bear at least two CCA-epitopes; while the CAA fraction contains molecules which contain at least two CAA-epitopes, and one CCA-epitope.
Qian
Z
Z
Department of Parasitology, Shanghai Second Medical University, Shanghai 200025.
Wang
Z
Z
Lu
P
P
Van Dam
G J
GJ
Deelder
A M
AM
D000818:Animals; D000947:Antigens, Helminth / Q000032:analysis / Q000302:isolation & purification*; D002432:Cecum / Q000276:immunology; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D006023:Glycoproteins / Q000032:analysis / Q000302:isolation & purification*; D015801:Helminth Proteins / Q000032:analysis / Q000302:isolation & purification*; D012547:Schistosoma / Q000276:immunology*
D000947:Antigens, Helminth; C091532:CCA protein, Schistosoma mansoni; D006023:Glycoproteins; D015801:Helminth Proteins; C090907:circulating anodic antigen, Schistosoma mansoni