A universal design of restructured dimer antigens: Development of a superior vaccine against the paramyxovirus in transgenic rice.

The development of vaccines, which induce effective immune responses while ensuring safety and affordability, remains a substantial challenge. In this study, we proposed a vaccine model of a restructured "head-to-tail" dimer to efficiently stimulate B cell response. We also demonstrate the feasibility of using this model to develop a paramyxovirus vaccine through a low-cost rice endosperm expression system. Crystal structure and small-angle X-ray scattering data showed that the restructured hemagglutinin-neuraminidase (HN) formed tetramers with fully exposed quadruple receptor binding domains and neutralizing epitopes. In comparison with the original HN antigen and three traditional commercial whole virus vaccines, the restructured HN facilitated critical epitope exposure and initiated a faster and more potent immune response. Two-dose immunization with 0.5 µg of the restructured antigen (equivalent to one-127th of a rice grain) and one-dose with 5 µg completely protected chickens against a lethal challenge of the virus. These results demonstrate that the restructured HN from transgenic rice seeds is safe, effective, low-dose useful, and inexpensive. We provide a plant platform and a simple restructured model for highly effective vaccine development.

Catastrophic health expenditure and health-related quality of life among older adults in Shandong, China: the moderation effect of daily care by adult children.

BACKGROUND: Catastrophic health expenditure (CHE) has a considerable impact on older people in later life, but little is known about the relationship between catastrophic health expenditure and health-related quality of life (HRQOL). The aim of this study was to examine the relationship between catastrophic health expenditure and health-related quality of life in older people, and to explore whether the daily care provided by adult children is a moderator in this relationship. METHODS: Data from the sixth National Health Services Survey in Shandong Province, China. The sample consisted of 8599 elderly people (age ≥ 60 years; 51.7% of female). Health-related quality of life was measured by the health utility value of EQ-5D-3 L. Interaction effects were analyzed using Tobit regression models and marginal effects analysis. RESULTS: The catastrophic health expenditure prevalence was 60.5% among older people in Shandong, China. catastrophic health expenditure was significantly associated with lower health-related quality of life (ß= - 0.142, P < 0.001). We found that adult children providing daily care services to their parents mitigated the effect of catastrophic health expenditure on health-related quality of life among older people (ß = 0.027, P = 0.040). CONCLUSIONS: Our findings suggested that catastrophic health expenditure was associated with health-related quality of life and the caring role of older adult children moderated this relationship. Reducing the damage caused by catastrophic health expenditure helps to improve health-related quality of life in older people. Adult children should increase intergenerational contact, provide timely financial and emotional support to reduce the negative impact of catastrophic health expenditure on health-related quality of life.

Development of a unique sandwich enzyme-linked immunosorbent assay based on monoclonal antibodies for the specific detection of the egg drop syndrome virus.

RESEARCH HIGHLIGHTS: A sandwich ELISA was developed to detect EDSV using the mAbs 5G4 and HRP-6G6.The sandwich ELISA maintained high specificity and sensitivity.The sandwich ELISA had equivalent consistency with real-time PCR assay.

Activities of daily living limitations and the use of physical examination among older adults with informal care in China: do gender and residence make differences?

BACKGROUND: This study investigated the relationship between activities of daily living (ADL) limitations and the use of physical examination among older adults receiving informal care, and to further examine whether this relationship varies by gender and urban-rural areas. METHODS: The data in this study were obtained from the sixth Health Service of Shandong province, China. In total, 8,358 older adults aged 60 years or older who received informal care were included in the analysis. Binary logistic regression models were conducted to explore the association between ADL limitations and the use of physical examination and examine the differences between gender and urban-rural areas. RESULTS: The prevalence of limitations in ADL and physical examination utilization rate among older adults receiving informal care in Shandong Province were 14.12% and 72.31%, respectively. After adjusting for confounders, ADL limitations were negatively correlated with the utilization of physical examination services among older adults receiving informal care (OR = 0.74, 95% CI: 0.64, 0.87, P < 0.001), and there were gender and rural-urban differences. The association between ADL limitations and the use of physical examination was statistically significant in older women receiving informal care (OR = 0.65, 95% CI: 0.53, 0.80, P < 0.001). And only among urban older adults receiving informal care, those with ADL limitations had lower utilization of physical examination services than participants without ADL limitations (OR = 0.59, 95% CI: 0.47, 0.74, P < 0.001). CONCLUSIONS: Our study suggested that the relationship between ADL limitations and the use of physical examination among older adults receiving informal care differed by gender and urban-rural areas in Shandong, China. These findings implied that the government should provide more health resources and personalized physical examination service programs, especially to meet the differential needs of women and urban old adults receiving informal care, to contribute to the implementation of healthy aging strategies.

Rice-produced classical swine fever virus glycoprotein E2 with herringbone-dimer design to enhance immune responses.

Pestiviruses, including classical swine fever virus, remain a concern for global animal health and are responsible for major economic losses of livestock worldwide. Despite high levels of vaccination, currently available commercial vaccines are limited by safety concerns, moderate efficacy, and required high doses. The development of new vaccines is therefore essential. Vaccine efforts should focus on optimizing antigen presentation to enhance immune responses. Here, we describe a simple herringbone-dimer strategy for efficient vaccine design, using the classical swine fever virus E2 expressed in a rice endosperm as an example. The expression of rE2 protein was identified, with the rE2 antigen accumulating to 480 mg/kg. Immunological assays in mice, rabbits, and pigs showed high antigenicity of rE2. Two immunizations with 284 ng of the rE2 vaccine or one shot with 5.12 µg provided effective protection in pigs without interference from pre-existing antibodies. Crystal structure and small-angle X-ray scattering results confirmed the stable herringbone dimeric conformation, which had two fully exposed duplex receptor binding domains. Our results demonstrated that rice endosperm is a promising platform for precise vaccine design, and this strategy can be universally applied to other Flaviviridae virus vaccines.

Physical Mobility, Social Isolation and Cognitive Function: Are There Really Gender Differences?

OBJECTIVE: This study aimed to examine the mediating role of social isolation between physical mobility and cognitive function, and whether there are gender differences in the above mediating effects among Chinese older adults. METHODS: This is a prospective and cohort study. We obtained data from the 2011 (Time 1, T1), 2015 (Time 2, T2) and 2018 (Time 3, T3) waves of China Health and Retirement Longitudinal Study, including 3,395 participants aged 60 years or above. Cognition was evaluated by Telephone Interview of Cognitive Status, words recall, and figure drawing, which was widely used in previous research. We used a cross-lagged model to test the hypothesis that social isolation mediated the association between physical mobility and cognitive function among Chinese older adults. RESULTS: The total effects of T1 physical mobility limitations on T3 cognitive function (ß = -0.055, bootstrap p < 0.001) were significantly negative. Social isolation played a mediating role among both males and females (male: ß = -0.008, bootstrap p = 0.012; female: ß = -0.006, bootstrap p = 0.023), demonstrating that the mediating effect of social isolation between physical mobility and cognitive function was not gender specific. CONCLUSION: This study confirmed that social isolation mediated the association between physical mobility and cognitive function among both Chinese male and female older adults. These findings indicate that reversing social isolation can be a priority intervention target for cognitive decline prevention and promote successful ageing, particularly among older adults with impaired physical mobility.

The relationship between handgrip strength and cognitive function among older adults in China: Functional limitation plays a mediating role.

BACKGROUND: The deterioration of cognitive function with age has become a major public health issue. To date, the underlying mechanisms of the association between handgrip strength and cognitive function were poorly understood. This study aimed to examine the mediating effect of functional limitation in the longitudinal relationship between handgrip strength and subsequent cognitive function. METHODS: This research recruited 4416 participants aged 60 and above from wave 2015 and 2018 of the China Longitudinal Study of Health and Retirement (CHARLS). We conducted the linear regression model and bootstrap analyses to test the mediating role of functional limitation in the relationship between handgrip strength and cognitive function. RESULTS: After adjusting the confounders, handgrip strength was positively associated with subsequent cognitive function (ß = 0.12, P < 0.001) and was negatively associated with functional limitation (ß = -0.14, P < 0.001). The mediation effect of functional limitation accounted for 23.33 % of the total effect regarding the handgrip strength with cognitive function, and the magnitude of mediation effect was a*b = 0.021 (95%CI: 0.017-0.027). LIMITATIONS: The variable of functional limitations was self-reported. And this study did not analyse the severity and duration of handgrip strength loss and functional limitations, which may lose some information. CONCLUSIONS: Our findings revealed that handgrip strength not only directly influenced cognitive function among older individuals but also indirectly via functional limitation over 3-year follow-up. Physical exercise targeting handgrip strength and functional limitation may be an effective approach to prevent and delay cognitive decline.

Thiolated chitosan encapsulation constituted mucoadhesive nanovaccine confers broad protection against divergent influenza A viruses.

Influenza A virus (IAV) poses a significant threat to human and animal health, necessitating the development of universal influenza vaccines that can effectively activate mucosal immunity. Intranasal immunization has attracted significant attention due to its capacity to induce triple immune responses, including mucosal secretory IgA. However, inducing mucosal immunity through vaccination is challenging due to the self-cleansing nature of the mucosal surface. Thiolated chitosan (TCS) were explored for mucosal vaccine delivery, capitalizing on biocompatibility and bioadhesive properties of chitosan, with thiol modification enhancing mucoadhesive capability. The focus was on developing a universal nanovaccine by utilizing TCS-encapsulated virus-like particles displaying conserved B-cell and T-cell epitopes from M2e and NP proteins of IAV. The optimal conditions for nanoparticle formation were investigated by adjusting the thiol groups content of TCS and the amount of sodium tripolyphosphate. The nanovaccine induced robust immune responses and provided complete protection against IAVs from different species following intranasal immunization. The broad protective effect of nanovaccines can be attributed to the synergistic effect of antibodies and T cells. This study developed a universal intranasal nanovaccine and demonstrated the potential of TCS in the development of mucosal vaccines for respiratory infectious diseases.

The impact of hypertension follow-up management on the choices of signing up family doctor contract services: does socioeconomic status matter?

BACKGROUND: This study aimed to explore the association between hypertension follow-up management and family doctor contract services, as well as to examine whether socioeconomic status (SES) had an interaction effect on this relationship among older adults in China. METHODS: We used data from the sixth National Health Service Survey of Shandong Province, China, including 3,112 older adults (age ≥ 60 years) with hypertension in 2018. Logistic regression models and a margins plot were used to analyze the role of SES in the relationship between hypertension follow-up management and family doctor contract services. RESULTS: The regular hypertension follow-up management rate and family doctor contracting rate were 81.8% and 70.9%, respectively, among older adults with hypertension. We found that participants with regular hypertension follow-up management were more likely to sign family doctor contract services (OR=1.28, 95%CI: 1.04, 1.58, P=0.018). The interaction effect occurred in the groups who lived in rural areas (OR=1.55, 95%CI: 1.02, 2.35), with high education level (OR=0.53, 95%CI: 0.32, 0.88) and had high incomes (OR=0.53, 95%CI: 0.35, 0.81). CONCLUSIONS: Our findings suggested that regular hypertension follow-up management was associated with family doctor contract services and SES influenced this relationship. Primary health care should improve the contracting rate of family doctors by strengthening follow-up management of chronic diseases. Family doctors should focus on improving services quality and enriching the content of service packages especially for older adults with higher income and education level.

Development and Evaluation of a Blocking Lateral Flow Assay Strip for Detection of Newcastle Disease Virus Antibodies.

Newcastle disease (ND) is an acute septicemic infectious disease caused by Newcastle disease virus (NDV). Considering that vaccination is currently the main modality for the prevention of ND, it is essential to assess the effectiveness of clinical immunization. In this study, we have developed a blocking lateral flow assay (bLFA) strip for the rapid detection of NDV antibodies using the monoclonal antibody 9C1 against haemagglutinin-neuraminidase (HN), which allows for the determination of an NDV-specific antibody titer within 10 min at room temperature. In addition, the bLFA strip has no cross-reactivity with the positive serum of other avian pathogens including avian influenza subtypes H5, H7, and H9, MD, IBD, IB, EDS, and avian adenovirus. The ability of the bLFA strip for detecting a neutralizing antibody was also estimated. The results showed that the chicken NDV hyperimmunized serum had a complete blocking (100%) titer of 11 log 2, and half-blocking titer of 13 log 2, which are 4 times less than and the same as that of the HI test (13 log 2), and 8 and 2 times less than that of the VN test (14 log 2), respectively. A total of 510 clinical samples were tested for NDV antibodies. The coincidence rate between the results of the bLFA strip and HI test was 97.65%. Therefore, it is an ideal alternative method for assessing the clinical immunity of ND vaccines in the field in real-time.

Activities of daily living limitations and family doctor contract services among overweight and obese older adults: is there a rural-urban difference?

BACKGROUND: The purpose of this study was to evaluate the relationship between activities of daily living (ADL) limitations and family doctor contract services among overweight and obese older adults, as well as to examine whether this association varies by urban-rural residence. METHODS: Data for the present study were obtained from the sixth Health Service of Shandong province, China. A total of 4,249 overweight and obese older adults were included in this study. Binary logistic regression models were used to evaluate the relationship between ADL limitations and family doctor contract services, to examine the potential differences between urban and rural areas. RESULTS: Of 4,249 overweight and obese older adults, the prevalence of limitations in ADL and family doctor service contracting rate in Shandong province were 12.47% and 66.46%, respectively. The results of the regression analyses revealed that overweight and obese older adults with ADL limitations were more likely to sign up for family doctor services than those without ADL limitations (OR = 1.27, 95%CI: 1.02-1.58, P = 0.033). Only among rural overweight and obese older adults, the relationship between ADL limitations and family doctor contract services was statistically significant (OR = 1.50, 95%CI: 1.13-1.99, P = 0.005). CONCLUSIONS: Our study found a significant association between ADL limitations and family doctor contract services among overweight and obese older adults in Shandong, China. This relationship differed by urban-rural residence. To promote the positive development of the family doctor contract service system, the government should increase publicity, provide personalized contracted services, and prioritize the healthcare needs of overweight and obese older adults with ADL limitations, with special attention to rural areas.

Emerging Hypervirulent Marek's Disease Virus Variants Significantly Overcome Protection Conferred by Commercial Vaccines.

As one of the most important avian immunosuppressive and neoplastic diseases, Marek's disease (MD), caused by oncogenic Marek's disease virus (MDV), has caused huge economic losses worldwide over the past five decades. In recent years, MD outbreaks have occurred frequently in MD-vaccinated chicken flocks, but the key pathogenic determinants and influencing factors remain unclear. Herein, we analyzed the pathogenicity of seven newly isolated MDV strains from tumor-bearing chickens in China and found that all of them were pathogenic to chicken hosts, among which four MDV isolates, SDCW01, HNXZ05, HNSQ05 and HNSQ01, were considered to be hypervirulent MDV (HV-MDV) strains. At 73 days of the virus infection experiment, the cumulative incidences of MD were 100%, 93.3%, 90% and 100%, with mortalities of 83.3%, 73.3%, 60% and 86.7%, respectively, for the four viruses. The gross occurrences of tumors were 50%, 33.3%, 30% and 63.3%, respectively, accompanied by significant hepatosplenomegaly and serious atrophy of the immune organs. Furthermore, the immune protection effects of four commercial MD vaccines against SDCW01, CVI988, HVT, CVI988+HVT, and 814 were explored. Unexpectedly, during the 67 days of post-virus challenge, the protection indices (PIs) of these four MD vaccines were only 46.2%, 38.5%, 50%, and 28%, respectively, and the birds that received the monovalent CVI988 or HVT still developed tumors with cumulative incidences of 7.7% and 11.5%, respectively. To our knowledge, this is the first demonstration of the simultaneous comparison of the immune protection efficacy of multiple commercial MD vaccines with different vaccine strains. Our study revealed that the HV-MDV variants circulating in China could significantly break through the immune protection of the classical MD vaccines currently widely used. For future work, there is an urgent need to develop novel, more effective MD vaccines for tackling the new challenge of emerging HV-MDV strains or variants for the sustainable control of MD.

Pathogenicity and Pathotype Analysis of Henan Isolates of Marek's Disease Virus Reveal Long-Term Circulation of Highly Virulent MDV Variant in China.

In recent years, outbreaks of Marek's disease (MD) have been frequently reported in vaccinated chicken flocks in China. Herein, we have demonstrated that four Marek's disease virus (MDV) isolates, HN502, HN302, HN304, and HN101, are all pathogenic and oncogenic to hosts. Outstandingly, the HN302 strain induced 100% MD incidence, 54.84% mortality, and 87.10% tumor incidence, together with extensive atrophy of immune organs. Pathotyping of HN302 was performed in comparison to a standard very virulent (vv) MDV strain Md5. We found that both CVI988 and HVT vaccines significantly reduced morbidity and mortality induced by HN302 or Md5 strains, but the protection indices (PIs) provided by these two vaccines against HN302 were significantly lower (27.03%) or lower (33.33%) than that against Md5, which showed PIs of 59.89% and 54.29%, respectively. These data suggested that HN302 possesses a significant higher virulence than Md5 and at least could be designated as a vvMDV strain. Together with our previous phylogenetic analysis on MDV-1 meq genes, we have presently suggested HN302 to be a typical highly virulent MDV variant belonging to an independent Chinese branch. To our knowledge, this is the first report to provide convincible evidence to identify a pathogenic MDV variant strain with a higher virulence than Md5 in China, which may have emerged and circulating in poultry farms in China for a long time and involved in the recent MD outbreaks.

Marek's disease virus encoded miR-M6 and miR-M10 are dispensable for virus replication and pathogenesis in chickens.

MicroRNAs (miRNAs) are a class of approximately 22 nucleotides long non-coding RNAs, and virus-encoded miRNAs play an important role in pathogenesis. Marek's disease virus (MDV) is an oncogenic avian alphaherpesvirus that causes immunosuppression and tumors in its natural host, chicken. In the MDV genome, 14 miRNA precursors and 26 mature miRNAs were identified, thus MDV has been used as a model to study the function of viral miRNAs in vivo. Recently, a cluster of miRNAs encoded by MDV, Cluster 3 miRNAs (miR-M8-M10), has been shown to restrict early cytolytic replication and pathogenesis of MDV. In this study, we further analyzed the role of miR-M6 and miR-M10, members of cluster miR-M8-M10, in MDV replication and pathogenicity. We found that, compared to parental MDV, deletion of miR-M6-5p significantly enhanced the replication of MDV in cell culture, but not in chickens. The replication of miR-M6-5p deletion MDV was restored once the deleted sequences were re-inserted. Our results also showed that deletion of miR-M10-5p did not affect the replication of MDV in vitro and in vivo. In addition, our animal study results showed that deletion of miR-M6-5p or miR-M10-5p did not alter the pathogenesis of MDV. In conclusion, our study shows that both miR-M6 and miR-M10 are dispensable for MDV replication and pathogenesis in chickens, while also suggests a repressive role of miR-M6 in MDV replication in cell culture.

Virus-encoded microRNA-M7 restricts early cytolytic replication and pathogenesis of Marek's disease virus.

MicroRNAs (miRNAs) are a class of ∼22 nucleotides non-coding RNAs that are encoded by a wide range of hosts. Viruses, especially herpesviruses, encode a variety of miRNAs that involved in disease progression. Recently, a cluster of virus-encoded miRNAs, miR-M8-M10, have been shown to restrict early cytolytic replication and pathogenesis of Marek's disease virus (MDV), an oncogenic avian alphaherpesvirus that causes lymphoproliferative disease in chickens. In this study, we specifically dissected the role of miR-M7, a member of cluster miR-M8-M10, in regulating MDV replication and pathogenesis. We found that deletion of miR-M7-5p did not affect the virus plaque size and growth in cell culture. However, compared to parental virus, infection of miR-M7-5p deletion virus significantly increased MDV genome copy number at 5 days post infection, suggesting that miR-M7 plays a role to restrict MDV replication during early cytolytic phase. In addition, our results showed that infection of miR-M7-5p deletion virus significantly enhanced the mortality of chickens, even it induced lymphoid organ atrophy similar to parental and revertant viruses. Taken together, our study revealed that the miR-M7 acts as a repressive factor of MDV replication and pathogenesis.

A novel linear epitope at the C-terminal region of the classical swine fever virus E2 protein elicits neutralizing activity.

Classical swine fever virus (CSFV) is a member of the genus Pestivirus, which causes serious economic losses. The re-emergence of the disease in Japan in 2018 has increased awareness of CSFV. In this study, Balb/c mice were immunized with plant-derived E2 protein, and four monoclonal antibodies (mAbs) 4B11, 7B3, 11A5 and 6F3 were generated. Two of these mAbs, 4B11 and 7B3, effectively blocked CSFV infection of PK-15 cells. Both mAbs recognized a novel linear epitope, 256CLIGNTTVKVHASDER271. The neutralizing ability of anti-CSFV serum decreased 63%, when pre-incubated with the linear peptide at 200 µg/mL. Structural analysis showed that this linear epitope is present at the border of Domain C and Domain D on the surface of the E2 protein. Alignment of amino acid sequences showed that the epitope was conserved in different subgroups of CSFV but not in other members of the Pestivirus genus. Consistently with the analysis above, this epitope distinguished antibodies against CSFV from those against bovine viral diarrhea virus (BVDV). Our study provides an ideal candidate peptide for new vaccine design and differential diagnosis of CSFV. These findings will contribute to the control and eradication of classical swine fever.

Identification of a dominant linear epitope on the VP2 capsid protein of porcine parvovirus and characterization of two monoclonal antibodies with neutralizing abilities.

Porcine parvovirus (PPV) is a major cause of reproductive failure in swine, and has caused huge losses throughout the world. The structural viral protein VP2, which is able to self-assemble into empty capsids, known as virus-like particles (VLPs), is crucial to induce PPV-specific neutralizing antibodies and protective immunity. In this study, twelve monoclonal antibodies (mAbs) against PPV were generated. The mAbs were characterized by indirect enzyme-linked immunosorbent assay (ELISA), western blotting (WB) and virus neutralization (VN) assay. Two mAbs were defined to be able to neutralize the standard PPV 7909 strain. Subsequently, peptide scanning was applied to identify linear epitopes. The peptide, 89ESGVAGQMV97 was defined as a precise linear epitope. Results from structural analysis showed that the epitope was exposed on the virion surface. Multiple sequence alignment analysis indicated that peptide 89ESGVAGQMV97 was not completely conserved, with a higher amino acid mutation rate at 91G, 92V and 93A position. Alanine-scanning mutagenesis further revealed that residues 89E, 90S, 91G, 92V and 94G were the core sites involved in antibody recognition. These findings may facilitate further understanding the function of the VP2 protein and development of diagnostic tools.

The broad-spectrum and ultra-sensitive detection of zeranol and its analogues by an enzyme-linked immunosorbent assay in cattle origin samples.

Zeranol (α-zearalanol) has been used as a growth promoter in livestock since 1969 in some non-EU countries; the residues of zeranol and its five analogues in animal origin foods may endanger human health due to their strong estrogenic and anabolic activities. Therefore, it is urgent to establish simple, rapid, real-time, broad-spectrum and high-sensitivity detection methods for the residues of zeranol and its analogues. In this study, an ultrasensitive indirect-competition enzyme-linked immunosorbent assay (ic-ELISA) was established for the rapid multi-residue detection of zeranol and its five analogues in cattle origin samples, which was based on a broad-spectrum monoclonal antibody (mAb) that specifically bound to zeranol and its analogues with high sensitivity. The half maximal inhibitory concentration (IC50) values for zeranol, ß-zearalanol, zearalanone, α-zearalenol, ß-zearalenol, and zearalenone were 0.103, 0.080, 0.161, 0.177, 0.254, and 0.194 ng mL-1, respectively, the recovery rates of cattle origin samples spiked with zeranol ranged from 79.2-104.2%, and the coefficient of variation (CV) values were less than 11.4%. Excellent correlation (R 2 = 0.9845) was obtained between the results of HPLC-MS/MS and ic-ELISA. In conclusion, the developed ic-ELISA could be employed as an ultrasensitive and broad-spectrum detection method for monitoring trace ZEN residues in cattle origin foods.

Marek's Disease Virus (Gallid alphaherpesvirus 2)-Encoded miR-M2-5p Simultaneously Promotes Cell Proliferation and Suppresses Apoptosis Through RBM24 and MYOD1-Mediated Signaling Pathways.

MicroRNAs (miRNAs) have been demonstrated for their involvement in virus biology and pathogenesis, including functioning as key determinants of virally-induced cancers. As an important oncogenic α-herpesvirus affecting poultry health, Marek's disease virus serotype 1 [Gallid alphaherpesvirus 2 (GaHV-2)] induces rapid-onset T-cell lymphomatous disease commonly referred to as Marek's disease (MD), an excellent biological model for the study of virally-induced cancer in the natural hosts. Previously, we have demonstrated that GaHV-2-encoded miRNAs (especially those within the Meq-cluster) have the potential to act as critical regulators of multiple processes such as virus replication, latency, pathogenesis, and/or oncogenesis. In addition to miR-M4-5p (miR-155 homolog) and miR-M3-5p, we have recently found that miR-M2-5p possibly participate in inducing MD lymphomagenesis. Here, we report the identification of two tumor suppressors, the RNA-binding protein 24 (RBM24) and myogenic differentiation 1 (MYOD1), being two biological targets for miR-M2-5p. Our experiments revealed that as a critical miRNA, miR-M2-5p promotes cell proliferation via regulating the RBM24-mediated p63 overexpression and MYOD1-mediated IGF2 signaling and suppresses apoptosis by targeting the MYOD1-mediated Caspase-3 signaling pathway. Our data present a new strategy of a single viral miRNA exerting dual role to potentially participate in the virally-induced T-cell lymphomagenesis by simultaneously promoting the cell proliferation and suppressing apoptosis.

Lorf9 deletion significantly eliminated lymphoid organ atrophy induced by meq-deleted very virulent Marek's disease virus.

Marek's disease virus (MDV) is a highly contagious alphaherpesvirus that causes rapid onset of T cell lymphomas in chickens. MDV continues to break through vaccinal immunity due to the emergence of highly virulent field strains. Earlier studies revealed that deletion of the meq gene from MDV results in attenuated vaccines that protect against disease when chickens are infected with highly virulent strains. However, meq-deleted viruses still retain the ability to induce lymphoid organ atrophy, which raises safety concerns. In an earlier study, we found that deletion of lorf9 counteracts this lymphoid organ atrophy. Here, we describe the generation of a double deletion mutant virus lacking virus-encoded meq and lorf9. In vitro studies revealed that during replication, the mutant virus had kinetic characteristics similar to the parental virus; however, in vivo the replication capability was significantly reduced. Results of animal studies revealed no obvious MDV-specific symptoms and lesions. Importantly, the double deletion mutant virus lost the capacity to induce lymphoid organ atrophy, which has been the main obstacle during development of a good vaccine candidate.