title: Identification of the gene family encoding the 160-kilodalton Trypanosoma cruzi complement regulatory protein.
abstract: Trypanosoma cruzi trypomastigotes are exquisitely resistant to the lytic effects of vertebrate complement, and this characteristic contributes to the survival of the parasites in the host bloodstream. Trypomastigotes avoid complement-mediated lysis by the production of a surface glycoprotein that inhibits the formation of the alternative and classical C3 convertase, thus preventing activation and amplification of the complement cascade at the parasite surface. We have developed a monoclonal antibody to the 160-kDa T. cruzi complement regulatory protein (CRP) and describe a one-step immunoaffinity purification procedure. The CRP was purified to homogeneity and subjected to amino-terminal peptide sequence analysis. Based on the protein sequence obtained, the CRP was identified as a member of a large family of trypomastigote-specific genes, and a complete cDNA was isolated and sequenced. The complete coding sequence was cloned in Escherichia coli, and antibodies raised against the full-length recombinant protein reacted specifically with a 160-kDa protein in trypomastigote membrane protein preparations as well as with native, purified CRP. Indirect immunofluorescence revealed that the protein is uniformly expressed at the cell surfaces of trypomastigotes.
authors.affiliation: Department of Molecular Genetics and Biochemistry, University of Pittsburgh School of Medicine, Pennsylvania 15261, USA. kan1@vms.cis.pitt.edu
authors.forename: K A
authors.initials: KA
authors.lastname: Norris
authors.forename: J E
authors.initials: JE
authors.lastname: Schrimpf
authors.forename: M J
authors.initials: MJ
authors.lastname: Szabo
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000096:biosynthesis / Q000737:chemistry; D001483:Base Sequence; D002846:Chromatography, Affinity; D003001:Cloning, Molecular; D003169:Complement Inactivator Proteins / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification; D018076:DNA, Complementary / Q000302:isolation & purification; D019084:Fluorescent Antibody Technique, Indirect; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification; D008969:Molecular Sequence Data; D008970:Molecular Weight; D005810:Multigene Family / Q000276:immunology*; D015800:Protozoan Proteins / Q000235:genetics* / Q000276:immunology* / Q000302:isolation & purification; D014349:Trypanosoma cruzi / Q000235:genetics* / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D003169:Complement Inactivator Proteins; D018076:DNA, Complementary; D008562:Membrane Glycoproteins; D015800:Protozoan Proteins; C103951:complement regulatory protein, Trypanosoma cruzi