title: Erythrocyte invasions and receptor heterogeneity in field isolates of Nanay river basin Iquitos.
abstract: OBJECTIVE
  To determine whether the requirements for sialic acid varies and whether several types of silaic acid independent receptors utilized for invasion mechanisms of fresh filed isolates collected around Nanay river basin, Iquitos.
  
  
  METHODS
  The field isolates were cultured as described previously by Jensen and Trager and MR4 protocol with little modifications. The erythrocytes preparation and subsequent enzyme treatment was done as described previously by Sharma. with little modification. Invasion assay was performed as described previously by Sharma et al with little modification.
  
  
  RESULTS
  The Nanay river basin isolates showed five types of invasion mechanisms or types of receptors-ligand interactions. Here we observed that an equal numbers of neuraminidase sensitive and resistant invasion receptor-ligand interaction profiles as the most common receptor-ligand invasion profiles. Neuraminidase resistance trypsin sensitive chymotrypsin sensitive (NM(R)T(S)CT(S)) invasion of receptor-ligand interaction profile was found in seven isolates, Five field isolates and one reference strain showed neuraminidase sensitive, trypsin sensitive and chymotrypsin resistant (NM(S)T(S)CT(R)) invasion of receptor-ligand interactions, six isolates including one reference strains dd2 showed neuraminidase sensitive, trypsin and chymotrypsin resistance (NM(S)T(R)CT(R)) indicating its dependence on sialic acids and independence of trypsin and chymotrypsin sensitive proteins. Four isolates showed neuraminidase sensitive, trypsin sensitive and chymotrypsin sensitive (NM(S)T(S)CT(S)) invasion of receptor-ligand interactions, seven isolates were neuraminidase resistant, trypsin sensitive and chymotrypsin resistance (NM(R)T(S)CT(R)) invasion of receptor-ligand interactions, indicating its dependence on trypsin sensitive proteins.
  
  
  CONCLUSIONS
  The Nanay river basin isolates showed five types of invasion mechanisms or types of receptors-ligand interactions. A full understanding of theses invasion mechanisms may allow the development of novel prophylactic and therapeutic strategies that block erythrocyte receptor-ligand invasion mechanisms.
authors: Laboratorio de Investigacion deproductos Naturales Antiparasitarios de la Amazonia, UNAP, Pampa chica, Iquitos, Peru 065.
authors: Kuppusamy
authors: K
authors: Chenniappan
authors: Sarah H
authors: SH
authors: Johns
mesh_terms: D000953:Antigens, Protozoan / Q000378:metabolism; D002918:Chymotrypsin / Q000008:administration & dosage; D004912:Erythrocytes / Q000276:immunology / Q000378:metabolism / Q000469:parasitology*; D006386:Hemagglutination Tests; D008562:Membrane Glycoproteins / Q000378:metabolism; D019158:N-Acetylneuraminic Acid / Q000378:metabolism*; D009439:Neuraminidase / Q000008:administration & dosage; D010568:Peru; D010963:Plasmodium falciparum / Q000302:isolation & purification / Q000378:metabolism / Q000472:pathogenicity*; D015800:Protozoan Proteins / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism; D011951:Receptors, Complement / Q000378:metabolism; D011971:Receptors, Immunologic / Q000378:metabolism; D063267:Sialic Acid Binding Ig-like Lectin 1; D014357:Trypsin / Q000008:administration & dosage; D014774:Virulence; D037521:Virulence Factors / Q000378:metabolism*
chemical_list: D000953:Antigens, Protozoan; D008562:Membrane Glycoproteins; D015800:Protozoan Proteins; D011956:Receptors, Cell Surface; D011951:Receptors, Complement; D011971:Receptors, Immunologic; D063267:Sialic Acid Binding Ig-like Lectin 1; D037521:Virulence Factors; D009439:Neuraminidase; D002918:Chymotrypsin; D014357:Trypsin; D019158:N-Acetylneuraminic Acid