Characterization of a cDNA-clone encoding Nc-p43, a major Neospora caninum tachyzoite surface protein.
Neospora caninum is an apicomplexan parasite of veterinary importance which invades many different cell types and tissues. N. caninum tachyzoites proliferate intracellularly by endodyogeny. Eventually the massive proliferation of tachyzoites leads to host cell lysis and the newly formed parasites are released and invade neighbouring cells. Tachyzoite cell surface molecules could serve as ligands, mediating host cell adhesion and invasion. Nc-p43 is a recently identified N. caninum tachyzoite surface protein which is functionally involved in the processes leading to host cell invasion in vitro. Affinity-purified antibodies directed against Nc-p43 were used to screen a lambda gt22A-cDNA expression library constructed from N. caninum tachyzoites. The cDNA insert of one immunoreactive clone was subcloned and expressed in E. coli as a poly-histidine fusion protein. The identity of the resulting recombinant antigen termed recNc-p43 was confirmed by immunoblotting, immunofluorescence and electron microscopy using affinity-purified antibodies. The sequence of the cDNA insert encoding recNc-p43 was determined. Analysis of the deduced amino acid sequence revealed that Nc-p43 exhibited similarity to SAG1 (p30) and SAG3 (p43), 2 major surface antigens of Toxoplasma gondii tachyzoites. These similarities were not reflected on the immunochemical level, since no cross-antigenicity between SAG1, SAG3 and Nc-p43 was observed.
Hemphill
A
A
Institute of Parasitology, University of Berne, Switzerland. hemphill@ipa.unibe.ch
Felleisen
R
R
Connolly
B
B
Gottstein
B
B
Hentrich
B
B
Müller
N
N
D000595:Amino Acid Sequence; D000818:Animals; D000953:Antigens, Protozoan / Q000737:chemistry / Q000235:genetics; D000954:Antigens, Surface / Q000737:chemistry / Q000235:genetics; D002522:Chlorocebus aethiops; D004251:DNA Transposable Elements; D018076:DNA, Complementary; D016054:DNA, Protozoan / Q000235:genetics*; D005455:Fluorescent Antibody Technique; D015723:Gene Library; D006790:Host-Parasite Interactions; D015151:Immunoblotting; D007150:Immunohistochemistry; D008562:Membrane Glycoproteins / Q000737:chemistry / Q000235:genetics; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D008969:Molecular Sequence Data; D018688:Neospora / Q000737:chemistry / Q000235:genetics* / Q000276:immunology / Q000648:ultrastructure; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D014122:Toxoplasma / Q000737:chemistry / Q000235:genetics; D014709:Vero Cells
D000953:Antigens, Protozoan; D000954:Antigens, Surface; D004251:DNA Transposable Elements; D018076:DNA, Complementary; D016054:DNA, Protozoan; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D015800:Protozoan Proteins; C047168:SAG1 antigen, Toxoplasma; C087692:SAG3 protein, Toxoplasma gondii; C110716:p43 protein, Neospora caninum