Plasmodium falciparum circumsporozoite (CS) protein peptides specifically bind to HepG2 cells

• Published in: Vaccine Vol. 19; no. 31; pp. 4487 - 4495
• Main Authors: Suarez, Jorge E., Urquiza, Mauricio, Puentes, Alvaro, Garcia, Javier E., Curtidor, Hernando, Ocampo, Marisol, Lopez, Ramses, Rodriguez, Luis E., Vera, Ricardo, Cubillos, Marcia, Torres, Maria H., Patarroyo, Manuel E.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Oxford Elsevier Ltd 14.08.2001; Elsevier
• Subjects: Amino Acid Sequence; Animals; Antigens, Protozoan - metabolism; Binding peptides; Binding, Competitive; Biological and medical sciences; Carcinoma, Hepatocellular; circumsporozoite protein; Epidemiology. Vaccinations; Fundamental and applied biological sciences. Psychology; General aspects; Hepatocytes - metabolism; Humans; Infectious diseases; Medical sciences; Molecular Sequence Data; Peptides - metabolism; Plasmodium falciparum; Plasmodium falciparum - metabolism; Protein Binding; Protozoa; Protozoan Proteins - metabolism; Tumor Cells, Cultured; Vaccines, antisera, therapeutical immunoglobulins and monoclonal antibodies; CS; Plasmodium falciparum; Binding peptides; Protozoa; Apicomplexa; Specificity; Peptides; Protein
• ISSN: 0264-410X; 1873-2518
• DOI: 10.1016/S0264-410X(01)00203-1

Hepatocyte invasion by malaria parasites is mediated by specific molecular interactions. Several lines of evidence suggest the importance of the surface plasmodial circumsporozoite (CS) protein in the sporozoite invasion of hepatocytes. Identification of the sequences involved in binding to hepatocytes is an important step towards understanding the structural basis for the sporozoite–hepatocyte interaction. In this study, binding assays between Plasmodium falciparum CS peptides and HepG2 cells were performed. Fifteen overlapping residue 20 mer long peptides, spanning the entire CS sequence, were tested in HepG2 cell binding assays. Five High Binding Activity Peptides (HBAPs) to HepG2 cells were identified: 4593, (NANPNANPNANP); 4383, (ṈS RS LGENḎDGṈNED NE KLR); 4388, (GNGQGHNM̱PNDP NRN VḎENA̱); 4389, (HNM̱PNDP NRN VḎENA̱NAṈSA̱) and 4390, (DP NRN VḎENA̱NAṈSA̱VKNṈN). The HBAP HepG2 interaction is independent of charge and amino-acid composition, but sequence dependent. Four HBAPs (4383, 4388, 4389 and 4390) are bound with similar affinity to a 50 kDa molecule. These HBAPs define three Hepatocyte Binding Sequences (HBSs): HBS-1, located between residues 68 and 87 (HBAP 4383); HBS-11, the repeat NANP region (HBAP 4593), for which anti repeat antibodies are able to specifically inhibit sporozoite invasion of hepatocytes have been reported; and HBS-111, between residues 286 and 315 (HBAPs 4388, 4388 and 4390), respectively. Interestingly, HBS 111 carries two earlier-reported B-epitopes (underlined) in peptides 4388, 4389 and 4390 (GNGQGHNM PNDPNRNVD ENANANSA VKNN) in its sequence. The HBSs reported here show lesser interspecie-variability than the entire protein in species invading the same kind of hepatic cells. This data supports these HBSs’ important role in CS-protein function; they could be used as ligand by the sporozoite to invade hepatic cells.