Characterization of Rubella Virus Strain Differences Associated with Attenuation

Abstract

A comparison of the phenotypic properties of three rubella vaccines (HPV77/DE5, RA27/3 and Cendehill) and four wild-type (wt⁺) isolates (M33, Therien, Thomas and IB2) has been carried out. Differences in growth characteristics, plaque morphology and temperature sensitivity were identified. In addition differential reactivity of the strains to polyclonal and a monoclonal anti-E1 antibody were found in immunoperoxidase-staining reactions. The ability of the wt⁺ and vaccine strains to infect lymphoreticular cells and chondrocytes, also varied in that the RA27/3 and Cendehill strains were highly restricted in both these cell types while the wt⁺ strains and HPV77/DE5 vaccine grew to high titer. This biological variation was associated with differences in E1 and E2 glycoproteins detected on immunoblots.

Mapping of Genetic Determinants of Rubella Virus Associated with Growth in Joint Tissue

“…3). Plaques from both the parent virus and the construct showed the characteristic "bull's-eye" appearance previously described for the Cendehill strain and readily differentiated from the microfoci produced by the Therien strain (9,42).…”

“…These studies indicate that one phenotypic property might be generated through a variety of mutations. That this occurs in RV is suggested by our observations that Cendehill and RA27/3 vaccine strains did not contain any mutations in common that were not also found in wt strain M33, although both share many phenotypic properties (9). This means that phenotypic traits shared between the two vaccine strains have been generated by different mutational events.…”

“…While these cross-neutralize (21), variation in phenotypic characteristics such as plaque morphology (25), temperature sensitivity, and cell tropism (9) has been noted. In particular, significant variation in the abilities of different strains to replicate and persist in joint tissue was found, and this arthrotro- pism was found to correlate closely with the association of different strains with the induction of joint symptoms in vivo.…”

“…However, the frequency and intensity of clinical symptoms reported for wild-type (wt) and vaccine strains correlate directly with the ability of the infecting strain to propagate in organ cultures of human synovial tissue, suggesting that tropism for joint tissue is a measure of viral arthritogenicity (31). Although RV strains are genetically around 98% homologous, they display striking phenotypic variation in growth characteristics and plaque morphology as well as tropism for joint tissue (9,31). The wt strains, such as Therien, which have the highest association with persistent joint symptoms (30%) (47), commonly replicate to titers of 10 6 to 10 7 PFU/ml in organ cultures of human joint tissue, comparable to the yields from the most permissive cell lines for RV.…”

Time-course induction of apoptosis by wild-type and attenuated strains of rubella virus

“…The Cendehill strain was obtained from SmithKline and French (Peetermans & Huygelen, 1967). Cendehill was chosen as it is more attenuated than the current vaccine strain, RA27/3 (Banatvala & Best, 1989;Chantler et al, 1993;Zygraich et al, 1971). RK13 cells were infected with RN and/or Cendehill strains of RV at an m.o.i.…”