Schistosoma mansoni: human serum and release of proteins from schistosomula

Radioiodinated surface proteins of schistosomula of Schistosoma mansoni, including those involved in low density lipoprotein binding, are released into a defined culture medium at 37 C at slower rates than proteins from schistosomula incubated in a serum-containing medium. When schistosomula were incubated at 4 C, a higher degree of reassociation of the same proteins into the parasites was detected. Purified human low density lipoproteins and a fraction containing very low density lipoprotein plus chylomicrons were also able to promote the release of iodinated proteins from the parasites. These observations suggest that serum may play a role in accelerating the turnover of membrane components in schistosomula.