Remembering mumps

Genome-wide determinants of cellular immune responses to mumps vaccine

BACKGROUND

We have previously described genetic polymorphisms in candidate genes that are associated with inter-individual variations in antibody responses to mumps vaccination. To expand upon our previous work, we performed a genome-wide association study (GWAS) to discover host genetic variants associated with mumps vaccine-induced cellular immune responses.

METHODS

We performed a GWAS of mumps-specific immune response outcomes (11 secreted cytokines/chemokines) in a cohort of 1,406 subjects.

RESULTS

Among the 11 cytokine/chemokines we studied, four (IFN-γ, IL-2, IL-1β, and TNFα) demonstrated GWAS signals reaching genome-wide significance (p < 5 × 10-8). A genomic region (encoding Sialic acid-binding immunoglobulin-type lectins/SIGLEC) located on chromosome 19q13 (p < 5 × 10-8) was associated with both IL-1β and TNFα responses. The SIGLEC5/SIGLEC14 region contained 11 statistically significant single nucleotide polymorphisms (SNPs), including the intronic SIGLEC5 rs872629 (p = 1.3E-11) and rs1106476 (p = 1.32E-11) whose alternate alleles were significantly associated with decreased levels of mumps-specific IL-1β (rs872629, p = 1.77E-09; rs1106476, p = 1.78E-09) and TNFα (rs872629, p = 1.3E-11; rs1106476, p = 1.32E-11) production.

CONCLUSIONS

Our results suggest that SNPs in the SIGLEC5/SIGLEC14 genes play a role in cellular and inflammatory immune responses to mumps vaccination. These findings motivate further research into the functional roles of SIGLEC genes in the regulation of mumps vaccine-induced immunity.

Safety analysis of a live attenuated mumps vaccine in healthy adolescents in China: A phase 4, observational, open-label trial

Mumps is an acute infectious disease, which was well controlled in the past, but recently it has resurged in some areas. This study aimed to evaluate the safety profile of the live attenuated mumps vaccine after large-scale vaccination. We conducted an observational, open-label phase 4 trial in Shaanxi, China from October 2020 to March 2021. Eligible participants were freshmen of junior high school who were not above 14 years old. Adverse events following immunization (AEFI) monitoring was carried out by active and passive surveillance. Safety follow-ups were conducted during the study participation. Overall, 10057 subjects were enrolled in the active surveillance analysis. A total of 214 subjects reported adverse reactions with an incidence of 2.13% (214/10057). Most adverse reactions were grade 1, and the incidence of grade 1 adverse reactions was 1.44% (145/10057); 0.60% for grade 2 (60/10057); and 0.09% for grade 3 (9/10057). The majority of adverse reactions were solicited (1.73%, 174/10057). Injection-site pain was the most frequently reported local adverse reaction (0.71%, 71/10057), followed by redness (0.29%, 29/10057). The most common systemic adverse reactions were nausea (0.19%, 19/10057) and fever (0.16%, 16/10057). For passive AEFI surveillance, 57 AEFI cases were reported, with an incidence of 19.28/100000 (57/287608). And most AEFI cases were common adverse reactions (66.67%, 38/57). In total, the live attenuated mumps vaccine evaluated in this trial has a favorable safety profile and can be used for large-scale inoculation.

Genome-Wide Determinants of Cellular Immune Responses to Mumps Vaccine

Background

We have previously described genetic polymorphisms in candidate genes that are associated with inter-individual variations in antibody responses to mumps vaccination. To expand upon our previous work, we performed a genome-wide association study (GWAS) to discover host genetic variants associated with mumps vaccine-induced cellular immune responses.

Methods

We performed a GWAS of mumps-specific immune response outcomes (11 secreted cytokines/chemokines) in a cohort of 1,406 subjects.

Results

Among the 11 cytokine/chemokines we studied, four (IFN-γ, IL-2, IL-1β, and TNFα) demonstrated GWAS signals reaching genome-wide significance (p<5 x 10 -8 ). A genomic region (encoding Sialic acid-binding immunoglobulin-type lectins/SIGLEC) located on chromosome 19q13 (p<5×10 -8 ) was associated with both IL-1β and TNFα responses. The SIGLEC5/SIGLEC14 region contained 11 statistically significant single nucleotide polymorphisms (SNPs), including the intronic SIGLEC5 rs872629 (p=1.3E-11) and rs1106476 (p=1.32E-11) whose alternate alleles were significantly associated with decreased levels of mumps-specific IL-1β (rs872629, p=1.77E-09; rs1106476, p=1.78E-09) and TNFα (rs872629, p=1.3E-11; rs1106476, p=1.32E-11) production.

Conclusions

Our results suggest that SNPs in the SIGLEC5/SIGLEC14 genes play a role in cellular and inflammatory immune responses to mumps vaccination. These findings motivate further research into the functional roles of SIGLEC genes in the regulation of mumps vaccine-induced immunity.

On the potentials of sialic acid derivatives as inhibitors for the mumps virus: A molecular dynamics and quantum chemistry investigation

Mumps virus is an infectious pathogen causing major health problems for humans such as encephalitis, orchitis, and parotitis. Therefore, designing an inhibitor for this virus is of great medical and public health importance. With this goal in mind, we investigate the affinity of different sialic acid-based compounds (ligands) against the hemagglutinin-neuraminidase (HN) protein of the mumps virus, using a combination of molecular dynamics (MD) simulations and quantum chemistry calculations. Our MD simulation results indicate that the ligands form stable complexes with the HN protein through a combination of electrostatic, van der Waals (vdW), and hydrogen bond (H-bond) interactions, which the electrostatic interactions play a more important role in the complexation process. Based on the obtained results from the structural analysis Arg381, Arg291, and Arg49 play a key role in the binding site interactions with the different ligands, in comparison with other residues. There are some candidates such as Neu5Acα2-6Galβ1-4GlcNAcβ, Neu5Acα2-3Galβ1-3GlcNacβ1-3Galβ1-4Glc, and Neu5Acα2-6Galβ1-4GlcNAcβ1-3Galβ1-4Glc that form more stable complexes with the HN than the α2-3-Sialyllactose confirmed by the calculated Gibbs binding energies (-39.65, -46.93, and -36.49 kcal.mol^-1, respectively). To investigate the relationship between the molecular properties of the selected compounds and their affinity to the HN receptor, density functional theory dispersion corrected (DFT-D3) calculations were employed. According to our DFT-D3 results, neutral sialic acid-based compounds have lower reactivity to the mumps virus than the negativity charge structures. Moreover, by increasing the electronic chemical potential (μ) the vdW and H-bond interactions between drugs and the HN protein increase. In other words, by elevating the electron tendency of the selected ligands their affinity to the mumps virus increases. Our quantum chemistry calculations reveal that in addition to the structural features the molecular properties of the drugs can play important roles in their affinity and reactivity against the virus. The results of this study can provide useful details to design new compounds or improve their properties against the mumps virus.

Mumps virus outbreak related to a water pipe (narghile) shared smoking

INTRODUCTION

This study describes a mumps outbreak among a group of young people who shared a same narghile to smoking. Saliva and blood samples were obtained from 3 cases for RT-PCR and serology respectively.

METHODS

The notification of a mumps case started an epidemiological investigation. Information of other 6 additional symptomatic persons who had gathered with the case in a discotheque where they smoking in a same narghile was achieved. RT-PCR positive samples were genotyped by sequencing.

RESULTS

The 7 patients resided in 3 different municipalities, and they do not have get together for more than a month until the meeting in the discotheque. Four cases were confirmed by RT-PCR and/or IgM determinations. The genomic investigation showed identical nucleic sequences.

CONCLUSIONS

This outbreak is consequence of the common use of a narghile to smoking. The public usage of these water pipes should be regulated.

Preparation of glycopolymers having sialyl α2 → 3 lactose moieties as the potent inhibitors for mumps virus

A water-soluble glycomonomer having a sialyl α2 → 3 lactose (SLac) moiety was prepared from a known imidate derivative of the SLac and an acrylamide alcohol by means of Schmidt's protocol followed by transesterification. Polymerization of the monomer proceeded in water as the solvent in the presence of ammonium persulfate (APS)-tetramethylethylenediamine (TEMED). Since acryl amide (AAm) was used as a regulator for the arrangement of sugar density, three kinds of glycopolymers having different sugar densities were obtained. Infection inhibition assays of mumps virus (MuV) for Vero cells using the glycopolymers were performed, and the results showed that a glycopolymer having a low sugar density has the highest inhibitory potency. In comparison to sialyl Lewis X (SLe^X) as the strongest inhibitor in a previous study, SLac polymer with the low sugar density showed ten-times stronger inhibitory potency than that of SLe^x. This finding suggested that multivalent conversion of the monomeric SLac with appropriate spatial arrangement are able to effectively inhibit the interaction between the attachment glycoprotein of MuV and glycan receptors on Vero cells.

Mumps virus outbreak related to a water pipe (narghile) shared smoking

INTRODUCTION

This study describes a mumps outbreak among a group of young people who shared a same narghile to smoking. Saliva and blood samples were obtained from 3cases for RT-PCR and serology respectively.

METHODS

The notification of a mumps case started an epidemiological investigation. Information of other 6additional symptomatic persons who had gathered with the case in a discotheque where they smoking in a same narghile was achieved. RT-PCR positive samples were genotyped by sequencing.

RESULTS

The 7patients resided in 3different municipalities, and they do not have get together for more than a month until the meeting in the discotheque. Four cases were confirmed by RT-PCR and/or IgM determinations. The genomic investigation showed identical nucleic sequences.

CONCLUSIONS

This outbreak is consequence of the common use of a narghile to smoking. The public usage of these water pipes should be regulated.

Mumps Outbreaks in Vaccinated Populations-Is It Time to Re-assess the Clinical Efficacy of Vaccines?

History illustrates the remarkable public health impact of mass vaccination, by dramatically improving life expectancy and reducing the burden of infectious diseases and co-morbidities worldwide. It has been perceived that if an individual adhered to the MMR vaccine schedule that immunity to mumps virus (MuV) would be lifelong. Recent mumps outbreaks in individuals who had received two doses of the Measles Mumps Rubella (MMR) vaccine has challenged the efficacy of the MMR vaccine. However, clinical symptoms, complications, viral shedding and transmission associated with mumps infection has been shown to be reduced in vaccinated individuals, demonstrating a benefit of this vaccine. Therefore, the question of what constitutes a good mumps vaccine and how its impact is assessed in this modern era remains to be addressed. Epidemiology of the individuals most affected by the outbreaks (predominantly young adults) and variance in the circulating MuV genotype have been well-described alluding to a collection of influences such as vaccine hesitancy, heterogeneous vaccine uptake, primary, and/or secondary vaccine failures. This review aims to discuss in detail the interplay of factors thought to be contributing to the current mumps outbreaks seen in highly vaccinated populations. In addition, how mumps diagnoses has progressed and impacted the understanding of mumps infection since a mumps vaccine was first developed, the limitations of current laboratory tests in confirming protection in vaccinated individuals and how vaccine effectiveness is quantified are also considered. By highlighting knowledge gaps within this area, this state-of-the-art review proposes a change of perspective regarding the impact of a vaccine in a highly vaccinated population from a clinical, diagnostic and public perspective, highlighting a need for a paradigm shift on what is considered vaccine immunity.

Roles of Sialic Acid, AXL, and MER Receptor Tyrosine Kinases in Mumps Virus Infection of Mouse Sertoli and Leydig Cells

The mumps virus (MuV) causes epidemic parotitis. MuV also frequently infects the testis and induces orchitis, an important etiological factor contributing to male infertility. However, mechanisms underlying MuV infection of the testis remain unknown. Here, we describe that sialic acid, AXL, and MER receptor tyrosine kinases regulate MuV entry and replication in mouse major testicular cells, including Sertoli and Leydig cells. Sialic acid, AXL, and MER were present in Sertoli and Leydig cells. Sialic acid specifically mediated MuV entry into Sertoli and Leydig cells, whereas both AXL and MER facilitated MuV replication within cells through the inhibition of cellular innate antiviral responses. Mechanistically, the inhibition of type 1 interferon signaling by AXL and MER is essential for MuV replication in Sertoli and Leydig cells. Our findings provide novel insights into the mechanisms behind MuV infection and replication in the testis.

Epidemiology of laboratory-confirmed mumps infections in South Africa, 2012-2017: a cross-sectional study

Background

Data on the burden of mumps in South Africa are limited and the epidemiology of mumps in this setting is not well understood. We present an analysis of mumps data in South Africa from 2012 to 2017.

Methods

This cross-sectional study included secondary data on laboratory-confirmed mumps infections from 2012 to 2017, archived at the South African National Health Laboratory Services’ data repository as well as from four private laboratories. Mumps-specific immunoglobulin M (IgM) and/or viral nucleic acid positive results represented acute infections. We used age-specific mid-year population estimates for each study year as denominators when calculating annual cumulative incidence. Seasonality was based on the season that showed a peak in infections.

Results

Out of 48,580 records obtained from the public and private sectors, 46,713 (96.2%) were from the private sector. Over the study period, there were 7494 acute infections, 7085 (94.5%) of which were recorded in the private sector. Of these 7494 infections, 3924 (52.4%) occurred in males. The proportion of samples tested that were IgM positive was 18.6% (1058/5682) in 2012, 15% (1016/6790) in 2013, 15.8% (1280/8093) in 2014, 15.5% (1384/8944) in 2015, 13.1% (1260/9629) in 2016 and 15.8% (1496/9442) in 2017. The cumulative incidence rate per 100,000 was highest in children between one and 9 years throughout the study period. The cumulative incidence of infections was highest in the Western Cape, Gauteng and the Northern Cape. Infections peaked in June and November.

Conclusion

Laboratory-confirmed mumps infections predominantly occurred in spring, affecting children below 10 years of age and individuals who were male. There were fewer tests performed in the public sector compared to the private sector. Since only laboratory data was analysed our results represent and underestimate of disease burden. Further studies that include clinical data are required to provide better estimates of disease burden in South Africa.

Structural basis for Glycan-receptor binding by mumps virus hemagglutinin-neuraminidase

Mumps virus is one of the main cause of respiratory illnesses in humans, especially children. Among the viral surface glycoproteins, the hemagglutinin - neuraminidase, MuV-HN, plays key roles in virus entry into host cells and infectivity, thus representing an ideal target for the design of novel inhibitors. Here we report the detailed analysis of the molecular recognition of host cell surface sialylated glycans by the viral glycoprotein MuV-HN. By a combined use of NMR, docking, molecular modelling and CORCEMA-ST, the structural features of sialoglycans/MuV-HN complexes were revealed. Evidence for a different enzyme activity toward longer and complex substrates compared to unbranched ligands was also examined by an accurate NMR kinetic analysis. Our results provide the basis for the structure-based design of effective drugs against mumps-induced diseases.

Immunogenicity and Safety of an F-Genotype Attenuated Mumps Vaccine in Healthy 8- to 24-Month-Old Children

Background

Mumps vaccine immunizations have reduced the incidence of this disease. With the variation of mumps circulating strain, novel vaccine strains are always important.

Methods

A 2-center parallel, randomized, double-blind noninferiority trial was performed to compare an F-genotype attenuated mumps vaccine (SP strain) to the A-genotype vaccine (S-79, Jeryl-Lynn strain) in 1080 healthy children aged 8-24 months in Hubei, China.

Results

Participants were randomly assigned to receive a high or low dose of the SP or S79 vaccine and then assessed clinically at 30 minutes and 1-28 days postinoculation. No differences in local or systemic reactivity were observed. A similar incidence of severe adverse events associated with the vaccine was observed in the high-dose group and the positive control group. Based on throat swab collections, no viral shedding was present at the 4th and 10th days in any group. Neutralizing and hemagglutination-inhibiting antibody assays with the F- or A-genotype strains showed similar trends in geometric mean titers in the high-dose SP and S79 groups. Increased cytotoxic T lymphocyte responses were observed in all groups.

Conclusions

The F-genotype attenuated mumps vaccine is safe, offers immunogenicity against a homologous virus, and is noninferior to the A-genotype vaccine in 8- to 24-month-old children.

Molecular Mechanism of the Flexible Glycan Receptor Recognition by Mumps Virus

Mumps virus (MuV) is an important aerosol-transmitted human pathogen causing epidemic parotitis, meningitis, encephalitis, and deafness. MuV preferentially uses a trisaccharide containing α2,3-linked sialic acid as a receptor. However, given the MuV tropism toward glandular tissues and the central nervous system, an additional glycan motif(s) may also serve as a receptor. Here, we performed a large-scale glycan array screen with MuV hemagglutinin-neuraminidase (MuV-HN) attachment proteins by using 600 types of glycans from The Consortium for Functional Glycomics Protein-Glycan Interaction Core in an effort to find new glycan receptor motif(s). According to the results of the glycan array, we successfully determined the crystal structures of MuV-HN proteins bound to newly identified glycan motifs, sialyl LewisX (SLeX) and the oligosaccharide portion of the GM2 ganglioside (GM2-glycan). Interestingly, the complex structures showed that SLeX and GM2-glycan share the same configuration with the reported trisaccharide motif, 3'-sialyllactose (3'-SL), at the binding site of MuV-HN, while SLeX and GM2-glycan have several unique interactions compared with those of 3'-SL. Thus, MuV-HN protein can allow an additional spatial modification in GM2-glycan and SLeX at the second and third carbohydrates from the nonreducing terminus of the core trisaccharide structure, respectively. Importantly, MuV entry was efficiently inhibited in the presence of 3'-SL, SLeX, or GM2-glycan derivatives, which indicates that these motifs can serve as MuV receptors. The α2,3-sialylated oligosaccharides, such as SLeX and 3'-sialyllactosamine, are broadly expressed in various tissues, and GM2 exists mainly in neural tissues and the adrenal gland. The distribution of these glycan motifs in human tissues/organs may have bearing on MuV tropism.IMPORTANCE Mumps virus (MuV) infection is characterized by parotid gland swelling and can cause pancreatitis, orchitis, meningitis, and encephalitis. MuV-related hearing loss is also a serious complication because it is usually irreversible. MuV outbreaks have been reported in many countries, even in high-vaccine-coverage areas. MuV has tropism toward glandular tissues and the central nervous system. To understand the unique MuV tropism, revealing the mechanism of receptor recognition by MuV is very important. Here, using a large-scale glycan array and X-ray crystallography, we show that MuV recognizes sialyl LewisX and GM2 ganglioside as receptors, in addition to a previously reported MuV receptor, a trisaccharide containing an α2,3-linked sialic acid. The flexible recognition of these glycan receptors by MuV may explain the unique tropism and pathogenesis of MuV. Structures will also provide a template for the development of effective entry inhibitors targeting the receptor-binding site of MuV.

MMRdb: Measles, mumps, and rubella viruses database and analysis resource

Measles, mumps, and rubella viruses are well known human pathogens that cause mild to severe illnesses. Despite the existence of MMR vaccines since 1971, outbreaks have been largely documented even in highly vaccinated populations. There is a pressing need to develop a resource to monitor genetic and antigenic variations among these viruses. Here, we introduced MMRdb, a web central database and analysis resource for measles, mumps, and rubella viruses. Users can search viruses at gene level and obtain sequence information based on gene product, geographic location, year, or host. The MMRdb also catalogs experimentally verified B cells and T cells antigenic epitopes data. A set of computation tools such as multiple sequence alignment, Geo Chart, and sequence similarity BLAST search has been implemented in a user-friendly database. The main features of this database will assist researchers in monitoring genetics and antigenic variations, tracking geographic spread with regards of sequence information, and facilitate the development of diagnostics, vaccines, and immunotherapeutics. Database URL: http://mmrdb.org.

Differential durability of immune responses to measles and mumps following MMR vaccination

The development and wide-spread use of mumps vaccine resulted in a dramatic and sustained decrease in the incidence of mumps disease; however, since 2000, an increase in the size and number of mumps outbreaks in the United States and other countries has sparked renewed interest in the durability of mumps-specific immunity elicited by mumps vaccination. The most likely explanation for mumps cases in previously immunized persons may be secondary vaccine failure, or waning immunity. In the current study, we examined changes in markers of measles and mumps immunity at two timepoints, approximately 7 and 17 years after two-dose MMR-II® vaccination, in a cohort of 98 healthy adults. Our results indicate that mumps IgG titers exhibited a large and significant decline during this time period, while mumps neutralizing Ab titers were relatively stable. There was a similar discrepancy with measles-specific immune responses. For both pathogens, neutralizing antibody titers were fairly low and, given the length of time since vaccination, may have already declined. These data suggest that specific immune outcomes may wane at different rates and highlight our currently incomplete understanding of protective immune responses to mumps and measles.

Imaging of Sialidase Activity and Its Clinical Application

Sialidase releases sialic acid residues from the ends of sugar chains. The sialidases are involved in many physiological processes including cell differentiation and proliferation and immune function as well as pathophysiological conditions such as various human cancers and infections. Therefore visualization of sialidase activities with high sensitivity could provide valuable insights into these isozyme's activity. We developed novel fluorescent sialidase substrates, 2-benzothiazol-2-yl-phenol derivatives-based N-acetylneuraminic acid (Neu5Ac) (BTP-Neu5Ac) substrates, for highly sensitive and specific visualization of sialidase activity in living mammalian tissues and virus-infected cells. We found that BTP-Neu5Ac can visualize sialidase activities sensitively and selectively in rat tissues including brain slices. BTP-Neu5Ac can also clearly detect cancer cells implanted orthotopically in mouse colons and human colon cancers. In this review, I describe imaging of sialidase activity with BTP-Neu5Ac in animal tissues, detection of colon cancer, memory formation, detection of virus-infected cells, and application to drug-resistant influenza virus detection and separation.

Molecular characteristics of mumps viruses isolated in Taiwan from 2006 to 2016

Sixteen mumps virus (MuV) sequences collected in Taiwan between 2006 and 2016 were characterized as genotype F (n = 1), G (n = 7), H (n = 4), J (n = 2), and K (n = 2). Mumps genotype F strain was imported from China in 2008 which was in accordance with the epidemic genotype in China. The Philippines was indicated as export country of three genotype H strains in 2007-2010 and Vietnam as export country of one genotype K strain in 2016 that matched with genotypes described in previous reports. Four strains of genotype G were imported from Japan, Thailand, Malaysia and Myanmar individually indicated that genotype G spreads widely in Asia as well as in the global. In this study, mumps strains of genotype G was first reported in relation to import from Malaysia and Myanmar. Furthermore, Indonesia was referred to export MuV of genotype J in 2007 for the first time. Molecular genotyping benefits the differentiation of circulating mumps viruses and can be used to investigate the transmission pathways. The dynamic genotypes of imported cases revealed the epidemic genotypes in nearby countries.

Three Complete Genome Sequences of Genotype G Mumps Virus from the 2016 Outbreak in Arkansas, USA

We present here the complete genome sequences of three mumps virus (MuV) strains isolated from patients who tested positive for the mumps virus during a mumps outbreak in Springdale, AR (USA), in 2016. The virus genomes, sequenced with Oxford Nanopore technology, belong to genotype G and have an average length of 15,342 nucleotides (nt).

Two-year antibody persistence in children vaccinated at 12-15 months with a measles-mumps-rubella virus vaccine without human serum albumin

One combined measles-mumps-rubella (MMR) vaccine without Human Serum Albumin (HSA) is currently licensed in the USA (M-M-R II; Merck, USA) and another has been developed (Priorix™ [MMR-RIT, GSK, Belgium]). In this follow-up study, children from USA or Puerto Rico, who had received one dose of M-M-R II or MMR-RIT at 12-15 months of age in the primary study (NCT00861744), were followed-up for 2 y post-vaccination. Anti-measles and anti-rubella antibodies were measured using Enzyme-Linked Immunosorbent Assay (ELISA), and anti-mumps antibodies using ELISA and plaque reduction neutralization (PRN) assays. Serious adverse events (SAEs) were recorded during the entire follow-up. The according-to-protocol (ATP) persistence cohort included 752 children (M-M-R II = 186, MMR-RIT = 566), who received primary vaccination at a mean age of 12.3 ( ± 0.67) months. 104 children were revaccinated with MMR-containing vaccines; therefore, serology results for timepoints after revaccination were excluded from the analysis. Seropositivity for measles (Year 1≥ 98.3%; Year 2≥ 99.4%) and rubella (Year 1≥ 98.9%; Year 2 = 100%) remained as high at Year 2 as at Day 42. Similarly, seropositivity for mumps determined by ELISA (Year 1≥ 90.1%; Year 2≥ 94.1%) and PRN assays (Year 1≥ 87.5%; Year 2≥ 91.7%) persisted. Thirty-three SAEs were recorded in 23 children; 2 SAEs (inguinal adenitis and idiopathic thrombocytopenic purpura) and one SAE (febrile convulsion) were considered as potentially related to MMR-RIT and M-M-R II, respectively. This study showed that antibodies against measles, mumps and rubella persisted for up to 2 y post-vaccination with either MMR vaccine in children aged 12-15 months, and that both vaccines were well-tolerated during the follow-up period.

A mumps model with seasonality in China

BACKGROUND

Mumps, an infectious viral disease, classically manifested by inflammation of salivary glands and is best known as a common childhood viral disease with no specific treatment. Although it can be protected by vaccine, there are more than 100,000 reported mumps cases according to the Chinese Center for Disease Control and Prevention. However, the factors and mechanisms behind the persistence and prevalence of mumps have not been well understood.

METHODS

A mumps model with seasonal fluctuation is formulated and investigated. We evaluate the basic reproduction number ℛ0 and analyze the dynamical behavior of the model. We also use the model to simulate the monthly data of mumps cases and carry out some sensitivity analysis of ℛ0 in terms of various model parameters.

RESULTS

It is shown that there exists only disease-free solution which is globally asymptotically stable if ℛ0 < 1, and there exists a positive periodic solution if ℛ0 > 1. ℛ0 is a threshold parameter, and its magnitude determines the extinction or persistence of the disease.

CONCLUSION

Our analysis shows that vaccination rate and invalid vaccination rate play important roles in the spread of mumps. Hence, Our study suggests to increase the vaccine coverage and make two doses of MMR (Measles, mumps and rubella vaccine) vaccine freely available in China.

[Molecular basis for negative-strand RNA virus entry and neutralization by antibodies]

Mononegaviruses are non-segmented negative-strand RNA viruses, and include measles, mumps, Marburg, and Ebola viruses. Measles virus and mumps virus, members of the family Paramyxoviridae, are immunotropic and neurotropic, respectively. Marburg virus and Ebola virus, members of the family Filoviridae, cause highly lethal hemorrhagic fever. In this paper, I summarize the recent structural and functional studies on the viral glycoproteins (GPs) of these viruses, which have shed light on virus entry and the humoral response. The structural and functional analyses of the interaction between viral GPs and receptors/antibodies also illuminate directions toward therapeutics against the viruses.

Trisaccharide containing α2,3-linked sialic acid is a receptor for mumps virus

Mumps virus (MuV) remains an important pathogen worldwide, causing epidemic parotitis, orchitis, meningitis, and encephalitis. Here we show that MuV preferentially uses a trisaccharide containing α2,3-linked sialic acid in unbranched sugar chains as a receptor. Crystal structures of the MuV attachment protein hemagglutinin-neuraminidase (MuV-HN) alone and in complex with the α2,3-sialylated trisaccharide revealed that in addition to the interaction between the MuV-HN active site residues and sialic acid, other residues, including an aromatic residue, stabilize the third sugar of the trisaccharide. The importance of the aromatic residue and the third sugar in the MuV-HN-receptor interaction was confirmed by computational energy calculations, isothermal titration calorimetry studies, and glycan-binding assays. Furthermore, MuV-HN was found to bind more efficiently to unbranched α2,3-sialylated sugar chains compared with branched ones. Importantly, the strategically located aromatic residue is conserved among the HN proteins of sialic acid-using paramyxoviruses, and alanine substitution compromised their ability to support cell-cell fusion. These results suggest that not only the terminal sialic acid but also the adjacent sugar moiety contribute to receptor function for mumps and these paramyxoviruses. The distribution of structurally different sialylated glycans in tissues and organs may explain in part MuV's distinct tropism to glandular tissues and the central nervous system. In the crystal structure, the epitopes for neutralizing antibodies are located around the α-helices of MuV-HN that are not well conserved in amino acid sequences among different genotypes of MuV. This may explain the fact that MuV reinfection sometimes occurs.