Mumps Virus Replication Research Articles

Replication of mumps virus in murine cells.

Mumps virus replication was examined in various culture cells derived from mice. Eight of 16 lymphoid cell lines and 4 of 13 non-lymphoid cell lines supported the replication of Vero cell-adapted Enders strain (EY) of mumps virus. EY strain replicated more efficiently in lymphoid cell lines than in non-lymphoid ones. T cell preference, however, was not observed in this study. The growth kinetics of EY strain in high yield cell lines such as EL-4, L1210 and NS-18 cells were similar to that in Vero cells, while in low yield cell lines such as DK, C243 and 203 GL cells the growth patterns varied respectively. Nineteen kinds of primary culture cells of murine origin all proved not to be susceptible for EY strain, even when spleen cells were stimulated with lectins or allogeneic cells. Seven other strains of mumps virus were examined for their ability to replicate in EL-4, L1210 and L929 cells. Four and 6 strains replicated in EL-4 cells and L1210 cells respectively, although the growth patterns and yields varied in each virus-cell combinations. On the other hand, none of 7 strains showed sufficient replication in L929 cells.

Biosynthesis of mumps virus F glycoprotein: non-fusing strains efficiently cleave the F glycoprotein precursor.

Mumps virus infection of the CV-1 cell line results either in no cytopathic effect or extensive cell fusion, depending upon the infecting mumps virus strain. Growth cycle analyses indicated that both types of infection were the result of multiple cycle replication of mumps virus. Intracellular virus-specific polypeptide synthesis was examined by pulse- and pulse-chase-labelling with radioactive amino acids and sugars. The major polypeptides seen on SDS-polyacrylamide gels were NP (69 000 mol. wt.), P (45 000 mol. wt.) and M (40 000 mol. wt.); a non-structural polypeptide (22 000 mol. wt.) was also present in infected cell lysates. The HN (74 000 to 79 000 mol. wt.) glycopolypeptide was detected in [3H]glucosamine- and [3H]mannose-labelled infected cells. A 65 000 mol. wt. species that had incorporated these precursors was seen in pulse-labelled infected cell lysates, and this glycopolypeptide vanished during the chase interval with the concomitant appearance of two glycopolypeptides (59 000 mol. wt. and 14 000 to 15 000 mol. wt.) which represented the F1 and F2 subunits of the F glycoprotein. Immunological data confirmed the relatedness of the 65 000 mol. wt. glycopolypeptide to the F glycoprotein and identified it as the precursor F0. The F0 precursor glycopolypeptide was seen in cells infected with both fusing and non-fusing strains, and F0 was processed completely to F glycoprotein for all infections. Thus, the lack of cell fusion after infection with certain mumps strains is not the consequence of incomplete processing of the F0 precursor.

Mumps virus-persistently infected cell cultures release defective interfering virus particles.

Summary Two human cell cultures, HEp-2 and L-41, persistently infected with mumps virus, produced small amounts of slowly replicating small-plaque infectious virus and detectable amounts of defective interfering virus particles which were similar to standard mumps virus in polypeptide composition, contained subgenomic size RNAs and interfered with standard mumps virus replication in susceptible cells.

Analysis of mumps virus defectiveness in vitro

The efficiency of mumps virus replication (EOR) was determined by comparing the multiplicity of infectious input (MOI) with the multiplicity of viral production (MOP). The replication kinetics of low passage wild, high passage laboratory and attenuated vaccine virus were evaluated using regular stock and cloned pools of virus (Table). The EOR of stock wild virus was 2.8, 4-fold greater than stock vaccine virus (0.7), and 300-fold greater than stock laboratory virus (0.009). The EOR of vaccine and laboratory virus was increased strikingly by double cloning, 0.7 to 2.0 and 0.009 to 3.7, respectively, while such limiting dilution hemadsorption plaquing techniques, employed to eliminate defective virions, reduced the EOR of wild virus (2.8 to 0.6).

Ultrastructure of Mumps Virus Replication in Organotypic Cultures of Hamster Choroid Plexus

Organotypic cultures of newborn hamster choroid plexus were inoculated with equal titre doses of newly isolated or hamster adapted strains of mumps virus. The ultrastructure of virus replication in choroid epithelial cells of the cultures was compared. No qualitative differences were observed; however, the adapted strain produced significantly greater numbers of virions and earlier destruction of the cultures. These findings are consistent with previous in vivo observations of the ultrastructure of the replication of these strains in the newborn hamster central nervous system. This in vitro study leads further support to the hypothesis that differences in the in vivo biological effects of the virus strains are primarily the result of virus-cell rather than virus-host interactions.

Paramyxovirus-avian cell relationship: discrepant impact of 6-azauridine on virus production by susceptible and less susceptible cells.

The replication of mumps virus in susceptible chicken embryonic heart cells was escalated by daily treatment of cultures with 6-azauridine (6-AU). On the other hand, virus production by less susceptible liver cells was depressed by 6-AU. The population of infected susceptible cells was not increased, but the release of virus by infected susceptible cells was enhanced 20-fold by 10 mug of 6-AU per ml. Less susceptible cells, which incorporated less ribonucleic acid and protein precursor than susceptible cells, sustained a constant level of viral release during 6-AU treatment; however, the number of infected less susceptible cells underwent substantial decline.

Ultrastructural characteristics of mumps virus replication in the cataracts of chick embryonic lens

Cataracts associated with mumps virus infection in early chick embryos were examined in the electron microscope. Their viral origin was confirmed by demonstrating that replication products typical of the paramyxovirus group were present in the lens fibres. The cytopathic effect was confined to the lens fibre cells, which constitute a developmental series of cells containing degenerating nuclei and differentiating towards anucleate forms. Both in these cells and in the cells of the anterior lens epithelium, eosinophilic inclusions were seen in the cytoplasm. These correlated with the large aggregates of material, apparently of viral nucleoprotein nature, seen in electron microscopy. Dense fibrillar aggregates, possibly composed of viral hemagglutinating protein, were also seen in the cytoplasm of the cells. In the fibre cells, tubular material of unknown nature and larger than true microtubules was detected in connection with the accumulated nucleoprotein. In spite of abundant accumulation of the intermediate products of viral replication, only a few mature viruses could be found in the lenses. It is suggested that the deficient viral maturation, abundant accumulation of intermediate products and locally-restricted cytopathic lesions may be correlated with the gradual cessation of nuclear functions in the fibre cells.

Mumps virus replication in chick embryo lung cells: properties of ribonucleic acids in virions and infected cells.

Ribonucleic acid (RNA) species in mumps virions and in infected cells were compared. The predominant RNA species in virions labeled with (3)H-uridine sedimented at 50S; RNA species sedimenting at 28, 18, and about 10S were also present. The virion-associated RNA species sedimenting slower than 50S contained some nucleotide sequences similar to 50S virion RNA. Although mumps virus replication was severely inhibited by high concentrations of actinomycin D, some virus was made, and virus-specific RNA species accumulated in infected cells. Mumps virus resembled other paramyxoviruses in inducing, in infected cells, synthesis not only of 50S RNA but also of slower sedimenting RNA species with a peak distribution at about 18S, complementary in base sequences to 50S virion RNA. In addition, base sequences of the parental type were relatively abundant in the RNA species sedimenting slower than 50S; these may represent precursors of the slowly sedimenting RNA species associated with virions. Ribonuclease-resistant RNA was detected in infected cells; this may represent replicative or transcriptive intermediates. Inhibition of protein synthesis with cycloheximide severely depressed accumulation of labeled 50S RNA in infected cells but did not interfere with accumulation of RNA species sedimenting slower than 50S. Actinomycin D treatment had a similar effect. Annealing of genomes and virus-induced complementary RNA species of Newcastle disease virus, Sendai virus, and mumps virus did not reveal any base sequence homologies.

A primitive immunoligic marker of intrauterine virus infection

Retrospective and prospective studies of the human have suggested that intrauterine mumps virus infection evokes an incomplete immunologic response of delayed hypersensitivity, without humoral antibody. Experimental infection of the subhuman primate during the first third of pregnancy also leads to the development of only cellular immunity in the infant offspring. The significance of delayed hypersensitivity as an immunologic marker of fetal infection is strengthened by the observation of an anamnestic neutralizing antibody response in 2 of 4 infant monkeys following a second skin test. Repeated skin testing of 5 seronegative adult monkeys failed to induce a primary antibody response. Intrauterine mumps virus infection illustrates the phylogenic and ontogenic concept that cellular immunity is the most primitive immunologic response. Experimental infection of 9 monkeys between the 25th–40th day of gestation, with subsequent cesarean section after 1, 2 and 3 weeks, has demonstrated that virus multiplies in the young fetus for only 1 week. Fetal interferon response does not occur, so the termination of viral replication seems to result from transplacental distribution of abundant 7S maternal neutralizing antibody. This conclusion is supported by the restrictive effect of antibody on mumps virus replication in vitro. Thus, the immature fetus confronts minimal antigenic mass and accrues immunopoietic instruction for only the more primitive response of delayed hypersensitivity.

Replication of mumps virus in human leukocyte cultures.

Duc-Nguyen, Huu (The Children's Hospital of Philadelphia, Philadelphia, Pa.), and Werner Henle. Replication of mumps virus in human leukocyte cultures. J. Bacteriol. 92:258-265. 1966.-Human peripheral leukocyte cultures maintained in the presence of phytohemagglutinin (PHA) were found to support to some extent the replication of mumps virus. When such cultures were exposed, within 24 hr after their initiation, to a high input multiplicity of virus, successful infection, as determined by immunofluorescence and plaque assays, did not become evident before the 3rd or 4th day. On exposure of cultures 4 to 5 days old, viral replication was detectable within 2 days. In both instances, peak immunofluorescence and virus titers were reached when the cultures were 7 to 9 days old and composed mainly of blast forms. With decreasing input multiplicities of infection, cells containing viral antigen and production of infectious viral progeny became detectable with increasing delay. No significant viral replication was noted in surviving cells maintained in the absence of PHA. These results indicate that mainly, if not solely, the PHA-stimulated cells of the lymphocytic series support viral multiplication. The extent of the infectious process was limited, however, because the life span of the cultures was not significantly shortened, the yields of infectious virus per immunofluorescent cell were at all times low, and most infected cells contained only a few well-delineated small masses of antigen, suggestive of an abortive infection. Only fresh cultures were capable of synthesizing interferon on stimulation by mumps, Newcastle disease, or Sendai viruses. When the cultures were set up in the presence of PHA, this capacity was lost within 24 hr. PHA per sefailed to induce detectable production of an interferon under the conditions used. The implications of these findings are discussed.

Mumps Virus Replication

Summary Although 84 to 99% of seed virus was adsorbed to chorioallantoic membranes of chick embryos within 2 hr after infection, only 1% or less of the introduced virus was recoverable during the latent period. The length of this latent period was found to be at least 20 hr. The development of hemagglutinins and viral complement-fixing antigens in general paralleled that of infective virus and a rapid release of virus and these viral components form cells was in evidence. The development of soluble antigen, however, showed a more specific relationship to infective virus and release of this component from cells (if indeed it did originate from cells) was considerably delayed. The treatment of viral particles with anesthetic ether released internal S antigen; the quantity of released internal S antigen was related to the original concentration of the viral sample. The V antigen titers decreased 4- to 32-fold and hemagglutinin titers for chicken cells dropped 32-fold or more as the result of other treatment.