SCHISTOSOMA-MANSONI - IN-VITRO AND IN-VIVO EXCRETION OF CAA AND CCA BY DEVELOPING SCHISTOSOMULA AND ADULT WORMS

In this study we describe the excretion patterns of circulating anodic (CAA) and cathodic antigen (CCA) by freshly transformed and developin g Schistosoma mansoni schistosomula and adult worms. In vitro, CAA and CCA were excreted by the parasites immediately after transformation. During the first days of development CAA and CCA levels were similar, but after 1 wk more CCA was excreted. Neither feeding the schistosomul a with red blood cells nor addition of colchicine influenced the rates of antigen excretion. Female worms produced more antigen than males. In heavily infected mice CCA was the first antigen detectable from the third week of infection onward. A few days later, CAA showed a steep increase, becoming the predominant antigen during the course of infect ion. In urine samples, obtained at the time of perfusion (7 wk), CCA w as the predominant antigen. In conclusion, although CAA and CCA levels in serum and urine generally correlate well with worm burden (as dete rmined by egg output), the present study and a literature review show that the actual quantities produced by the worms and detected in the h ost circulation or excreta may depend on many factors, e.g., host and parasite species, clearance rates, or duration and intensity of infect ion.