Maturation of IgG avidity to individual rubella virus structural proteins.
BACKGROUND
the structural proteins of rubella virus, the capsid protein C and the envelope glycoproteins E1 and E2 were produced in lepidopteran insect cells using baculovirus expression vectors. The C-terminal ends of the corresponding proteins were fused to a polyhistidine tag for easy and gentle purification by metal ion affinity chromatography.


OBJECTIVE
to investigate the maturation of natural and vaccinal IgG avidity against individual authentic and recombinant rubella virus (RV) structural proteins.


METHODS
the analysis was carried out using a modified immunoblotting technique where the purified baculovirus-expressed proteins were compared with authentic rubella virus proteins. Altogether, 47 well-characterised serum samples from both naturally infected patients and vaccines were studied.


RESULTS
after natural RV infection, IgG antibodies specific for the E1 protein were predominant not only in terms of levels, but also in terms of rate and magnitude of avidity maturation. The avidity development of the IgG antibodies was much slower in vaccines than in patients after a natural RV infection.


CONCLUSIONS
together, our results indicate that IgG avidity determination in conjunction with immunoblot analysis is useful in the diagnosis of a RV infection. The recombinant proteins showed similar reactivity patterns in the immunoblot analyses as compared with the authentic viral structural proteins, suggesting suitability for serodiagnostics.
Nedeljkovic
J
J
Institute of Immunology and Virology, Torlak, Belgrade, Yugoslavia.
Jovanovic
T
T
Oker-Blom
C
C
D000914:Antibodies, Viral / Q000097:blood / Q000276:immunology*; D000915:Antibody Affinity / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology*; D012409:Rubella / Q000097:blood / Q000276:immunology*; D012411:Rubella Vaccine / Q000276:immunology; D012412:Rubella virus / Q000276:immunology; D014611:Vaccination; D014758:Viral Core Proteins / Q000276:immunology*; D014759:Viral Envelope Proteins / Q000276:immunology*
D000914:Antibodies, Viral; D007074:Immunoglobulin G; D012411:Rubella Vaccine; D014758:Viral Core Proteins; D014759:Viral Envelope Proteins; C074573:nucleocapsid protein (C), rubella virus; C061826:E1 envelope protein, Rubella virus; C061827:E2 envelope protein, Rubella virus