Large-Scale Purification of Rubella Virus and Preparation of an Experimental Split Rubella Virus Vaccine

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The hemolysis-in-gel (HIG) technique was adapted for rubella antibody determinations. Use of sucrose gradient purified virus and its coupling with CrCl3 to chicken erythrocytes resulted in gel plates that could be stored for several weeks and were suitable for reproducible antibody determinations. In a serological survey of young healthy adults the HIG values (range less than 2--13 mm) were in close correlation to those obtained by the HI test (less than 10 5o 320). The Hig test seems well suited for screening the need of vaccination. Seronegative sera (HIG less than 2,HI less than 10) gave without heat inactivation hemolysis zones ranging from 4 to 6.5 mm. Although the present rubella HIG test did not measure IgM antibodies, the test, by virtue of its accuracy and sensitivity--extending to antibody levels corresponding to HI titers 2--10--provides a simpler and more rapid means for diagnosis of rubella infections than the conventional HI and CF tests.

Hemolysis‐in‐gel test in immunity surveys and diagnosis of rubella

Väänänen

Vaheri

1979

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Evaluation of solid‐phase enzyme‐lmmunoassay procedure in immunity surveys and diagnosis of rubella

Vaheri

Salonen

1980

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In the development of optimized micro-and macromethods for solid-phase rubella enzyme-immunoassay (EIA), the effect of various technical parameters was studied. Special emphasis was placed on elimination of defective polystyrene material, purity and quantity of immobilized antigen, use of reference sera in each microplate or macroprocedure, use of nonionic detergent in washing and diluent buffers, and use of a colourless enzyme substrate. A single serum dilution, analysed in duplicate, was sufficient provided the procedure was standardized. In quantitation of serum rubella antibodies, EIA gave values correlating well with those obtained with the single radial haemolysis test but not with low haemagglutination inhibition titres. The EIA procedure proved to be a useful and reliable serological tool in immunity surveys. When complemented by a rubella IgM test, EIA could also be used in diagnosis of recent rubella infections as a convenient primary serological test.

Maturation of immunoglobulin G avidity after rubella vaccination studied by an enzyme linked immunosorbent assay (Avidity‐ELISA) and by haemolysis typing

Hedman

Hietala

Tiilikainen

et al. 1989

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Two tests were introduced recently for assessment of the avidity of rubella immunoglobulin antibodies. In the quantitative test--avidity-enzyme linked immunosorbent assay (ELISA)--IgG antibodies obtained from individuals shortly after primary infection with rubella virus are distinguished from those with past immunity by their antigen-elution characteristics. This method uses agents that disrupt hydrophobic bonds in proteins [Kamoun PP (1988): Denaturation of globular proteins by urea: Breakdown of hydrophobic bonds? Trends in Biological Sciences 13:424-425.]. In the semiquantitative, presumptive test--haemolysis typing--the low-avidity rubella-IgG antibodies are distinguished from the high-avidity antibodies by the quality of their haemolytic zones in a radial haemolysis test. In the present study, both tests were applied to sera taken before and after vaccination with two different strains (Cendehill or RA 27/3) of live attenuated rubella virus. It was found that after vaccination of previously nonimmune subjects, IgG synthesized during the first 2 months had a very low avidity; IgG avidity increased dramatically during the subsequent 4 months and less markedly between 6 and 12 months after vaccination. On the contrary, the initially high IgG avidity of previous immune vaccinees remained at an elevated level postvaccination. These results provide a basis for identification of recent primary rubella virus infections, or vaccination reactions, by the avidity of specific IgG and also for their separation from rubella reinfections.