A new attenuated rubella virus grown in human fibroblasts: evidence for reduced nasopharyngeal excretion

Are Measles-Mumps-Rubella (MMR) Antibodies Friends or Foes for Covid-19 Disease?

Many factors have been implicated in the pathogenesis and severity of COVID-19 pandemic. A wide variation in the susceptibility for SARS-CoV-2 infection among different population, gender and age has been observed. Multiple studies investigated the relationship between the antibody's titre of previously vaccinated individuals and the susceptibility of coronavirus infection, to find a rapid effective therapy for this pandemic. This study focused on the association between measles-mumps-rubella (MMR) antibodies titre and the severity of COVID-19 infection. We aimed to investigate the correlation between the antibody's titre of MMR and the SARS-CoV-2 infection susceptibility and disease severity, in a cohort of COVID-19 Egyptian patients, compared to a control group. MMR antibody titre was measured using enzyme Linked Immune Sorbent Assay; (ELISA) for 136 COVID-19 patients and 44 healthy individuals, as control group. There were high levels of measles and mumps antibodies titer in the deteriorating cases, which could not protect from SARS-CoV-2 infection. However, the rubella antibodies might protect from SARS-CoV-2 infection, but once the infection occurs, it may aggravate the risk of case deterioration. MMR antibodies could be used as a guideline for COVID-19 symptom-severity and, in turn, may be considered as an economic prognostic marker used for early protection from multiple autoimmune organ failure.

The key role of rubella virus glycoproteins in the formation of immune response, and perspectives on their use in the development of new recombinant vaccines

Rubella is a highly contagious viral disease which is mostly threatens to women of reproductive age. Existent live attenuated vaccines are effective enough, but have some drawbacks and are unusable for a certain group of people, including pregnant women and people with AIDS and other immunodeficiency. Thereby the development of alternative non-replicating, recombinant vaccines undoubtedly is needed. This review discusses the protein E1 and E2 role in formation of immune response and perspectives in development of new generation recombinant vaccines using them.

Matrix and backstage: cellular substrates for viral vaccines

Vaccines are complex products that are manufactured in highly dynamic processes. Cellular substrates are one critical component that can have an enormous impact on reactogenicity of the final preparation, level of attenuation of a live virus, yield of infectious units or antigens, and cost per vaccine dose. Such parameters contribute to feasibility and affordability of vaccine programs both in industrialized countries and developing regions. This review summarizes the diversity of cellular substrates for propagation of viral vaccines from primary tissue explants and embryonated chicken eggs to designed continuous cell lines of human and avian origin.

[The life cycle of Rubella Virus]

Rubella virus (RV), an infectious agent of rubella, is the sole member of the genus Rubivirus in the family of Togaviridae. RV has a positive-stranded sense RNA as a genome. A natural host of RV is limited to human, and rubella is considered to be a childhood disease in general. When woman is infected with RV during early pregnancy, her fetus may develop severe birth defects known as congenital rubella syndrome. In this review, the RV life cycle from the virus entry to budding is illustrated in comparison with those of member viruses of the genus alphavirus in the same family. The multiple functions of the RV capsid protein are also introduced.

Chimeric derivatives of hepatitis B virus core particles carrying major epitopes of the rubella virus E1 glycoprotein

Three variants of the major rubella virus (RV) E1 protein virus-neutralizing epitope from position 214 to 285 were exposed on the hepatitis B virus (HBV) C-terminally truncated core (HBcΔ) in a virus-like particle (VLP) vector and were produced in Escherichia coli. All three chimeras demonstrated VLPs in bacterial cell lysates, but only HBcΔ-E1(245-285) demonstrated the correct VLP structure after purification. The other chimeras, HBcΔ-E1(214-285) and HBcΔ-E1(214-240), appeared after purification as non-VLP aggregates of 100 to 900 nm in diameter according to dynamic light scattering data. All three variants possessed the intrinsic antigenic activity of RV E1, since they were recognized by natural human anti-RV E1 antibodies and induced an anti-RV E1 response in mice. HBcΔ-E1(214-240) and HBcΔ-E1(245-285) can be regarded as prototypes for a putative RV vaccine because they were able to induce antibodies recognizing natural RV E1 protein in RV diagnostic kits.

Measles, mumps, and rubella virus vaccine (M-M-R™II): a review of 32 years of clinical and postmarketing experience

M-M-R™II (measles, mumps, and rubella virus vaccine live; Merck, Sharp, & Dohme Corp.) is indicated for simultaneous vaccination against measles, mumps, and rubella in individuals ≥ 12 months of age. Before the vaccine era, these viruses infected most exposed individuals, with subsequent morbidity and mortality. One of the greatest achievements of public health has been to eliminate these 3 diseases in large geographic areas. The safety profile of M-M-R™II is described using data from routine global postmarketing surveillance. Postmarketing surveillance has limitations (including incomplete reporting of case data), but allows collection of real-world information on large numbers of individuals, who may have concurrent medical problems excluding them from clinical trials. It can also identify rare adverse experiences (AEs). Over its 32-year history, ≈ 575 million doses of M-M-R™II have been distributed worldwide, with 17,536 AEs voluntarily reported for an overall rate of 30.5 AEs/1,000,000 doses distributed. This review provides evidence that the vaccine is safe and well-tolerated.

The History of Rubella and Rubella Vaccination Leading to Elimination

Congenital rubella syndrome (CRS) was discovered in the 1940s, rubella virus was isolated in the early 1960s, and rubella vaccines became available by the end of the same decade. Systematic vaccination against rubella, usually in combination with measles, has eliminated both the congenital and acquired infection from some developed countries, most recently the United States, as is confirmed by the articles in this supplement. The present article summarizes the clinical syndrome of CRS, the process by which the vaccine was developed, and the history leading up to elimination, as well as the possible extension of elimination on a wider scale.

Improved potency assay of rubella vaccine: parameters for plaque formation

Parameters for plaque formation by rubella vaccine strains licensed in Japan were studied. Formation of clear and large plaques on RK13 cells depends on several essential parameters. Plaques differed in morphology among five vaccine strains and the distinctiveness of the plaques was affected by pH of the agar overlay medium during incubation at 35 degrees C. Plaques became progressively larger in size as the concentration of sodium bicarbonate in the agar overlay medium increased from 0.04% to 0.15%, but the contrast of plaques to the background cells decreased markedly. The most distinct plaques of all vaccine strains were formed in the agar overlay medium containing 0.07% of sodium bicarbonate, i.e., pH 6.83, incubated in a humidified atmosphere containing 5% CO2. The number of plaques formed by vaccine strains decreased at 37 degrees C. Vaccine strains other than MEQ11 and TCRB19 formed larger and more contrasted plaques with sharp outline at 35 degrees C than at 32 degrees C. MEQ11 and TCRB19 strains yielded higher infective virus titres at 32 degrees C, but they formed distinct plaques at 35 degrees C and 32 degrees C. For the plaque test, the inoculum volume was another critical factor for obtaining an approximate titre that reflected the absolute titre of the sample. A volume of 0.1 ml was feasible for a well with a diameter of 35 mm.

Rubella vaccines: past, present and future

The association between rubella in pregnancy and congenital anomalies was first reported 50 years ago, by N. McAlister Gregg, an Australian ophthalmologist [1]. During the next 20 years his findings were confirmed by others (reviewed in [2]). However, the first reports of the isolation of rubella virus in cell cultures and development of tests for neutralizing antibodies were not published until 1962 [3, 4]. Subsequent studies conducted in the UK and North America during a pandemic of rubella in 1963–4, were therefore able to make a more accurate estimate of the risks of maternal rubella at different stages of pregnancy. It was estimated that about 30000 rubella-damaged babies were born in the USA alone in 1963–4 [5]. This emphasized the importance of developing a vaccine to prevent infection in pregnancy and thereby, the birth of babies with rubella-induced congenital defects.

Nucleotide sequence of the 24S subgenomic messenger RNA of a vaccine strain (HPV77) of rubella virus: comparison with a wild-type strain (M33)

A full-length cDNA clone for the 24S subgenomic mRNA of the vaccine strain (HPV77) of rubella virus has been isolated from a cDNA library made from the RNAs of infected cells. Starting from the first Met start codon, the 24S mRNA codes for a precursor protein of 1063 amino acids (aa). This precursor encodes a capsid protein of 300 aa, and two envelope proteins, E1 (481 aa) and E2 (282 aa). Both the E1 and E2 proteins are preceded by a stretch of 21 hydrophobic aa, characteristic of a signal peptide, and each has three putative glycosylation sites in the polypeptide chains. Comparison between the structural proteins of the vaccine and the wild-type (wt; M33) strains of rubella virus, revealed that the E2 protein of the vaccine strain differs, in its apparent Mr, by approx. 3 kDa, from the wt strain. The difference could be due to decreased glycosylation of the vaccine strain E2 protein, as revealed by [3H]mannose incorporation studies. Five single-aa changes in the structural proteins occurred during the attenuation process, one each in the capsid and the E1 protein and three in the E2 protein. The change of Thr-412----Ile in the E2 protein results in the loss of a putative glycosylation site at Asn-410, which offers a plausible explanation for decreased glycosylation of the E2 protein from the vaccine strain of rubella virus.

Rubella virus: mechanism of attenuation in the vaccine strain (HPV77)

The vaccine type (HPV77 strain) of rubella virus replicates slower and manifests a delayed appearance of cytopathic effect in Vero-76 cells as compared to wild-type virus (M33). The change in cytopathic effect coincides with the delayed appearance of both genomic and subgenomic RNA as well as viral structural proteins in the cell. The delay in the appearance of the viral proteins in the cells was also evident when the cells infected with the vaccine-type virus were treated with the lysosomotropic agent such as chloroquine. Binding studies using [35S]methionine-labeled virus showed that the vaccine-type virus bound to the cells poorly and the binding was not completely competed out with the cold virus.

Vaccines produced by conventional means to control major infectious diseases of man and animals

This chapter reviews the development of some of vaccines and their use in controlling such major diseases as diphtheria, rinderpest, Newcastle disease, smallpox, pertussis, yellow fever, rabies, etc. Park–Williams Number 8 (PW8) strain is used to make diphtherial toxoid for vaccines. As a source of toxin, it is rendered nontoxic by incubation with formalin under alkaline conditions. The product's retention of antigenicity, enabling it to induce antitoxin antibodies, makes it an excellent pediatric vaccine. Vaccine against Rinderpest Virus was developed by Koch in 1897 by administering bile from infected cattle. Animals that survived were permanently immune. Formalin- and chloroform-inactivated vaccines were developed using tissues from the infected animals. For the control of Newcastle disease, a number of attenuated live-virus vaccines have been developed which are widely used to control the disease. The Bl strain, the LaSota strain, and the F strain are used to immunize birds of all ages by different routes, including by addition to drinking water and by spraying. Protection against rabies correlates with SN antibody, which can be assessed by a number of tests. Pasteur's classical vaccine, developed from infected spinal cord tissue dried at room temperature for 3–14 days, was given in a series of 21–28 inoculations beginning with material dried the longest and progressing through material dried for only 3 days.

Generation of defective-interfering particles by rubella virus in Vero cells

The generation of defective-interfering (DI) particles by rubella virus during serial undiluted passage and persistent infection in Vero cells was studied. A series of 24 serial undiluted passages was initiated with plaque-purified virus. The virus titer remained relatively constant through the first nine passages, after which it declined, reaching a low level of 20-fold less than the originating stock by passage 15. In subsequent passages, the titer cycled. Intracellular DI RNAs were first detectable at passage 4, at which time DI RNAs of 7500 and 1400 nucleotides in length were observable. Thus, the rate of which DI RNAs were generated by rubella virus during serial undiluted passage was similar to the rate of DI generation by other enveloped RNA viruses during serial undiluted passage. The longer rubella DI RNA was present in all passages subsequent to passage 4, while the 1400-nucleotide DI RNA was replaced by a DI RNA of 800 nucleotides in length by passage 15. Subsequent to passage 7, the relative amount of genomic RNA declined dramatically and the DI RNAs became the predominant intracellular virus-specific RNA species. Negative-polarity RNA species corresponding to the 7500- and 800-nucleotide DI RNA species were identified. The 7500- and 1400-nucleotide DI RNA species were encapsidated into virus particles while the presence of the 800-nucleotide DI RNA species in virus particles could not be detected. Interestingly, the rubella virus subgenomic RNA was present in virus particles in preparations containing DI RNAs. A persistent infection was initiated by subculturing the surviving cells from a high multiplicity of infection with plaque-purified virus. Intracellular DI RNAs were first detectable at Day 19 after initiation of persistence and became significant by Day 26. The amount of genomic RNA began to decrease at Day 47 and was undetectable after Day 68. Through Day 54, there were several DI RNA species present, but at later times, one of these species became predominant. Thus, DI particles were generated during persistent infection, but their presence was not necessary for initiation of persistence.

Rubella virus replication: effect of interferons and actinomycin D

The effect of alpha and gamma interferon (IFN alpha, IFN gamma) and actinomycin D on the expression of wild type rubella virus in African green monkey kidney cells (Vero 76) was studied. Viral protein synthesis in the infected cells was significantly reduced upon treatment of the cells with IFN alpha or IFN gamma, which is accompanied by the reduction in the level of both the (+) stranded and the (-) stranded viral RNAs. The residual rubella viral RNA from interferon-treated cells, however, was structurally intact as judged by Northern blot analysis and in vitro translation. These results suggest that the effect of IFN alpha and IFN gamma on rubella viral protein synthesis is both at the transcriptional and the translational level. The effect of actinomycin D on rubella virus replication was found to be time-dependent. It is much more pronounced during the eclipse phase of the viral growth (first 4 h) than after 8 h at which time actinomycin D had lesser effect. A similar effect on rubella virus replication was observed when alpha-amanitin was used instead of actinomycin D. These results were taken to indicate that during the viral infection, host cell DNA directs the synthesis of a cellular factor(s) which is essential for the viral replication. When the synthesis of this cellular factor(s) is terminated at an early stage of viral infection by actinomycin D or by alpha-amanitin, viral replication is impaired.

Genetic and molecular mechanisms of viral pathogenesis: implications for prevention and treatment

The pathogenesis of infection of mice by the mammalian reoviruses involves several discrete steps. Each of the three viral outer capsid proteins has a highly distinct and specialized role: one protein (sigma 1) binds to cell surface receptors; a second protein (mu 1C) determines the capacity for viral growth at mucosal surfaces; and the third protein (sigma 3) is responsible for inhibiting cell macromolecular synthesis. A detailed picture of the molecular basis of reovirus virulence and attention is now emerging.

Rubella immunity testing by mixed hemadsorption

A mixed hemadsorption (MH) test for naturally acquired rubella immunity and immune responses after rubella vaccination has been compared with the hemagglutination-inhibition (HI) test, the immunodiffusion (ID) test, the neutralization test (NT), the hemolysis-in-gel (HIG) test and the indirect immunofluorescence (IF) test. The MH test was approximately equivalent to the HI test and the NT as to sensitivity for the early response to rubella vaccination, and all three tests are thought to measure protective antibodies, i.e. antibodies supposedly directed against envelope antigens, to about the same extent. The MH test for rubella antibodies is especially suited for laboratories in which this type of test is routinely used for other purposes, e.g. rabies, respiratory syncytial virus, herpes simplex, varicella and certain auto-antibodies. Where the method is already standard it may be preferable to the NT which, although of similar clinical value requires tedious standardization. Both tests may be necessary in cases where the HI test is equivocal or hampered by non-removable on-specific inhibitors.

Genetic variation during lytic reovirus infection: high-passage stocks of wild-type reovirus contain temperature-sensitive mutants

Wild-type clones of reovirus serotypes 1 (Lang), 2 (Jones), and 3 (Dearing) were serially passaged in L cells at a high multiplicity of infection, and the virus population was examined at passage levels 2, 5, and 11 for the presence of temperature-sensitive (ts) mutants. By passage 11 all three serotypes contained ts mutants that were not present in the original wild-type stock. ts mutants representing three mutant groups were identified. The majority of these mutants were in group G. Our results show that high-passage stocks of reovirus consist of a genetically heterogeneous population.

Maternal rubella at St. Thomas' Hospital: is there a need to change British vaccination policy?

During the 28 weeks starting April 3, 1978, 269 pregnant women were assessed serologically because of exposure to or development of rubella-like illnesses, this number being four times greater than that during either of the previous 2 years. Only 33 (12%) of these patients had previously been given rubella vaccine. Rubella was confirmed serologically in 17 patients; among patients attending antenatal clinics the overall risk of acquiring infection was about 1 in 155. The mean age of patients acquiring maternal rubella was 27.9 years, and all but 1 had left school before the rubella vaccination programme started. 55 (92%) of 60 household contacts were children, of whom 24 (40%) were of preschool age and 13 (21.7%) aged less than 2 years. The interval between contact and presentation for serological studies was often long and, because of this, 79 sera had to be tested for virus-specific IgM. No drastic change in rubella vaccination policy is required but there should be more emphasis on vaccination of women of childbearing age.

Rubella screening and immunization of schoolgirls: a long-term evaluation

A three-year rubella immunization programme is described in which 9,231 Edinburgh schoolgirls were screened for rubella antibodies. Of these girls 2,519 (27·3%) were found to have rubella HAI titres of < 32, and 2,258 were immunized with either Cendehill or RA27/3 rubella vaccine. Of those who were immunized, 99% were found to have detectable HAI antibody two months later.

From the first cohort (born in 1956) 1,072 girls have been enrolled in a 20-year programme to study the long-term value of these rubella vaccine strains; 536 of these girls had an initial HAI titre of < 32 and were immunized with rubella vaccine or remained at risk because they refused immunization. Each girl has been paired with another who was found to be immune by natural infection. Of the 1,072 girls concerned, 1,031 (96%) remained in the programme at the end of the first year. Further serological tests at this time showed that 93% of all girls had HAI titres that were either stable or within a twofold variation of the previous sample.

Vaccination of adults with Wistar RA 27/3 rubella vaccine

Thirty-three adults were vaccinated subcutaneously with Wistar RA. 27/3 (live attenuated) rubella vaccine at the Wellcome Research Laboratories, Beckenham. All subjects with pre-vaccination haemagglutinating-inhibiting antibody titres of 1/20 or less and three of seven subjects with pre-vaccination titres of 1/40 showed at least fourfold rises of titre. Reactions encountered were mild and of short duration.

Frequency of rubella antibodies among adult population in Greece

No significant sex difference in the incidence of immunity to rubella at the ages of 20–25 was found in a comparative study of young adults from the Greater Athens area as well as from the rural department of Corinthia. The immunity to rubella of Greek adults on a national scale was then studied in a respresentative sample of 1200 males 20–25 years old. In 83·2% of them neutralizing antibodies to rubella were detected. A statistically higher proportion of immunes was found among those from urban areas. The factors responsible for the relative prevalence of immunity to rubella in various population groups are discussed.

Rubella vaccine trial in children

A study with RA 27/3 attenuated rubella virus vaccine (Plotkin strain) showed that this produced a significant antibody response in all of twenty-one vaccinated non-immune children without any appreciable marked clinical reactions. Serological examination of 53 non-immune and 29 immune siblings living in the same households failed to show any evidence of transmission of infection.

Clinical and laboratory studies with rubella vaccines in adults

Three live attenuated rubella vaccines were tested in adult volunteers. Clinical reactions were mild, but were more noticeable in vaccinated non-immune subjects than in control subjects. With the exception of two individuals, all of the remaining 54 subjects developed an immune response; the level of antibodies found was somewhat lower than that resulting from natural infection. Though virus could be isolated from some of the seronegative volunteers after vaccination, no evidence was found of transmission of infection.