Clearance of artificial immune complexes consisting of circulating cathodic antigen and monoclonal antibodies in Schistosoma mansoni infected mice

The clearance patterns of intravenously injected model immune complexes (IC) consisting of monoclonal antibodies and the Schistosoma mansoni derived circulating cathodic antigen (CCA) were analyzed in S. mansoni infected mice. The size distribution of the preformed immune complexes analyzed by sucrose density gradient ultracentrifugation revealed a strong heterogeneity in the molecular weight of the IC. The molecular weight of CCA, as derived from SDG-analysis, was estimated to be lower than 40 kD. In infected mice the clearance of the injected IC was at least as sufficient as in uninfected controls. The initial clearance of the injected immune complexes was significantly faster when they contained a high proportion of IC heavier than 7S. Antibody clearance was faster in infected mice than in uninfected mice; this was attributed to improved clearance after complexation with free circulating antigen. SDG-analysis of serum samples 30 min after injection of IC and antibody only revealed the presence of a 7S component consisting of small IC or uncomplexed antibody. The tissue distribution of the injected material was dependent on the size of the injected IC. A fast clearance of heavy IC was associated with an increased accumulation of these complexes in the liver. The clearance results are discussed in the context of the potential involvement of CCA in the development of glomerulopathies in schistosomiasis.