Schistosoma mansoni: relationship between turnover rates of membrane proteins and susceptibility to immune damage of schistosomula.

Both dialysed fetal calf serum (DFCS) and concanavalin A (Con A) are known to decrease the susceptibility of schistosomulum of Schistosoma mansoni to damage by antibody and complement in vitro. The effects of DFCS and Con A on the synthesis and turnover rate of individual proteins in the surface membranes have been measured. DFCS increases the synthesis and turnover rate of low molecular weight proteins while Con A decreases the synthesis and turnover rate of high molecular weight proteins. It is suggested that DFCS and Con A act by different mechanisms to alter the properties of the surface membrane and that in vivo both mechanisms operate to protect the membrane against immune damage.