This Article Order Full text via Infotrieve Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Chiang, C. P. Articles by Caulfield, J. P. Search for Related Content PubMed PubMed Citation Articles by Chiang, C. P. Articles by Caulfield, J. P.

American Journal of Pathology, Vol 135, 1015-1024, Copyright © 1989 by American Society for Investigative Pathology

REGULAR ARTICLES

Human lipoprotein binding to schistosomula of schistosoma mansoni. Displacement by polyanions, parasite antigen masking, and persistence in young larvae

CP Chiang and JP Caulfield
Department of Rheumatology, Harvard Medical School, Boston, Massachusetts.

It was previously shown by the authors that the binding of human low- density lipoprotein (LDL) to the surface of schistosomula inhibits the binding of human anti-schistosomal antibodies and is inhibited by suramin. Here, three questions were considered. 1) Are LDLs bound to schistosomula displaced from the membrane by polyanions? 2) Does bound LDL mask or hide antigens recognized by human anti-schistosomal antibodies? 3) Is LDL, binding capability present when the larvae enter the blood stream? The first question was tested by measuring the percentage of the schistosomular surface membrane covered by LDL after exposure to LDL with or without dextran sulfate or suramin. The bound LDL was visualized with polyclonal goat anti-human apolipoprotein B (anti-apo B) antibodies and peroxidase-conjugated secondary antibodies. After overnight culture in 20 micrograms/300 microliters LDL, 84.0% +/- 0.3% of the parasite surface was covered by LDL reaction product. When the polyanions suramin or dextran sulfate were added to the cultures for 30 minutes, only 59.7% +/- 4.9% of the surface was covered by reaction product, demonstrating that the LDL was partially displaced from the membrane by these compounds. The second question was tested by measuring the binding of human and mouse monoclonal anti-schistosomal antibodies before and after exposure to LDL, with or without partial removal of the bound LDL by suramin. LDL partially inhibited antibody binding in a reversible fashion. The LDL clearly masked parasite antigens, most probably by steric hindrance. However, there may be competitive inhibition of antibody binding by the LDL as well, because human anti-schistosomal antibodies inhibited LDL binding to worms and both human anti-schistosomal antibody and LDL binding to schistosomula were inhibited by suramin. Finally, the third question was tested by quantitative immunofluorescence. The LDL binding capability persisted and nearly doubled by 72 hours after transformation from cercariae. These experiments demonstrated that LDL bound to the surface of schistosomula through the time they enter the blood stream. LDL bound to the parasite surface may help the parasite to evade antibody- dependent cytotoxic reactions by masking parasite antigens.

This article has been cited by other articles:

				E. A. G. REIS, M. G. REIS, R. DE CASSIA R. SILVA, T. M. A. CARMO, A. M. O. ASSIS, M. L. BARRETO, I. M. PARRAGA, M. L. P. SANTANA, and R. E. BLANTON BIOCHEMICAL AND IMMUNOLOGIC PREDICTORS OF EFFICACY OF TREATMENT OR REINFECTION RISK FOR SCHISTOSOMA MANSONI Am J Trop Med Hyg, November 1, 2006; 75(5): 904 - 909. [Abstract] [Full Text] [PDF]

				L. Camacho-Lobato and D. R. Borges Plasma Proteins of Hemostasis in the Hepatointestinal Form of Schistosomiasis Mansoni Clinical and Applied Thrombosis/Hemostasis, October 1, 1996; 2(4): 276 - 278. [Abstract] [PDF]

				R. Rogers, R. Jack, and S. Furlong Lipid and membrane protein transfer from human neutrophils to schistosomes is mediated by ligand binding J. Cell Sci., January 10, 1993; 106(2): 485 - 491. [Abstract] [PDF]

				S. T. Furlong, K. S. Thibault, and R. A. Rogers Fluorescent phospholipids preferentially accumulate in sub-tegumental cells of schistosomula of Schistosoma mansoni J. Cell Sci., November 1, 1992; 103(3): 823 - 830. [Abstract] [PDF]