Efficacy and safety of mRNA1273 SARS-CoV-2 vaccination in hematopoietic stem cell transplant recipients: Single center experience

Background: COVID-19 represents a worldwide pandemic and vaccination remains the most effective preventive strategy. Among hematological patients, COVID-19 has been associated with a high mortality rate. Vaccination against SARS-CoV-2 has shown high efficacy in reducing community transmission, hospitalization and deaths related to severe COVID-19 disease. However, patients with impaired immunity may have lower sero-responsiveness to vaccination.MethodsThis study focuses on hematopoietic stem cell transplantation (HSCT) recipients. We performed a unicenter, prospective, observational study of a cohort of 31 allogeneic and 56 autologous-HSCT recipients monitored between March 2021 and May 2021 for serological response after COVID-19 vaccination with two doses of mRNA1273 vaccine (Moderna). In order to determine seroconversion, serological status before vaccination was studied.ResultsAt a median range of 75 days after the second vaccine dose, seroconversion rates were 84% and 85% for the autologous and allogeneic-HSCT groups, respectively. We confirmed some potential risk factors for a negative serological response, such as receiving anti-CD20 therapy in the previous year before vaccination, a low B-lymphocyte count and hypogammaglobulinemia. Neutralizing antibodies were quantified in 44 patients, with a good correlation with serological tests. Adverse events were minimal.ConclusionmRNA1273 vaccination is safe and effective in HSCT recipients, especially in those presenting recovered immunity. (AU)

Introducción: Entre los pacientes hematológicos, la COVID-19 se ha asociado a una mayor mortalidad. La vacunación frente a SARS-CoV-2 es la principal estrategia de prevención y ha demostrado eficacia en la reducción de la transmisión, de la hospitalización y de la tasa de mortalidad. Aun así, los pacientes oncohematológicos con un sistema inmunológico disfuncional podrían presentar una respuesta menor a la vacunación.MétodosEstudio unicéntrico, prospectivo y observacional, con una cohorte de 31 receptores de un trasplante alogénico de progenitores hematopoyéticos y de 56 receptores de un trasplante autólogo que recibieron la vacunación frente a SARS-CoV-2 entre marzo de 2021 y mayo de 2021, con 2 dosis de la vacuna mRNA1273 (Moderna). Para poder determinar la tasa de seroconversión, se determinó el estado serológico previamente a la vacunación y posteriormente se monitorizó la respuesta serológica.ResultadosCon un tiempo medio de seguimiento de 75 días después de la segunda vacuna, la tasa de seroconversión fue del 84%, y del 85% en el grupo receptor de trasplante autólogo y alogénico, respectivamente. Se confirmaron algunos potenciales factores de riesgo para la ausencia de respuesta serológica, como haber recibido terapias anti-CD20, un recuento bajo de linfocitos B y la hipogammaglobulinemia. En 44 pacientes se cuantificaron títulos de anticuerpos neutralizantes, con buena correlación con los test serológicos. Los efectos adversos de la vacuna fueron mínimos.ConclusiónLa vacunación con mRNA1273 es segura y efectiva en los pacientes receptores de un trasplante de progenitores hematopoyéticos, especialmente en los que presentan reconstitución inmune previa. (AU)

Self-Assembled STING-Activating Coordination Nanoparticles for Cancer Immunotherapy and Vaccine Applications.

The cGAS-STING pathway plays a crucial role in innate immune activation against cancer and infections, and STING agonists based on cyclic dinucleotides (CDN) have garnered attention for their potential use in cancer immunotherapy and vaccines. However, the limited drug-like properties of CDN necessitate an efficient delivery system to the immune system. To address these challenges, we developed an immunostimulatory delivery system for STING agonists. Here, we have examined aqueous coordination interactions between CDN and metal ions and report that CDN mixed with Zn2+ and Mn2+ formed distinctive crystal structures. Further pharmaceutical engineering led to the development of a functional coordination nanoparticle, termed the Zinc-Mn-CDN Particle (ZMCP), produced by a simple aqueous one-pot synthesis. Local or systemic administration of ZMCP exerted robust antitumor efficacy in mice. Importantly, recombinant protein antigens from SARS-CoV-2 can be simply loaded during the aqueous one-pot synthesis. The resulting ZMCP antigens elicited strong cellular and humoral immune responses that neutralized SARS-CoV-2, highlighting ZMCP as a self-adjuvant vaccine platform against COVID-19 and other infectious pathogens. Overall, this work establishes a paradigm for developing translational coordination nanomedicine based on drug-metal ion coordination and broadens the applicability of coordination medicine for the delivery of proteins and other biologics.

Spatial clusters of human and livestock anthrax define high-risk areas requiring intervention in Lao Cai Province, Vietnam 1991-2022.

Anthrax, a widespread zoonosis in low and middle-income countries with low disease awareness and insufficient livestock vaccination coverage, has been known in Lao Cai Province in northern Vietnam for years before its apparent absence in 2009, which requires investigation as this infection is frequently reported from neighbouring provinces and countries. We aimed to describe the seasonal patterns of anthrax (1991-2008), compare livestock anthrax vaccine coverage to disease occurrence (1991- 2022), and delineate the high-risk areas to inform local disease surveillance in the province. We illustrated the seasonal pattern of anthrax and provided a comparison between livestock vaccine coverage and disease occurrence by purely spatial SaTScan (Poisson model, 25% population at risk) to detect spatial clusters of human and livestock anthrax using population derived from zonal statistics routines. The number of cases, crude cumulative incidence, and spatial clusters of human and livestock anthrax were mapped in QGIS. Results indicate peak anthrax incidence from May to October. Buffalo, domestic cattle, and horses accounted for 75% of total animal cases. Horse anthrax was more common in Lao Cai than in its neighbours and often occurred in years with human mortality. Vaccination covered less than 30% of the livestock population. We found an apparent pattern where anthrax was controlled from 1998-2003 with higher vaccine coverage (>20%) and identified spatial clusters of human and livestock anthrax in Muong Khuong, Bao Thang, and Bac Ha districts of Lao Cai. The local public health and veterinary agencies are recommended to revisit the high-risk areas and communicate with neighbouring provinces for a regional approach to anthrax surveillance and control.

The global patent landscape of emerging infectious disease monkeypox.

BACKGROUND: Monkeypox is an emerging infectious disease with confirmed cases and deaths in several parts of the world. In light of this crisis, this study aims to analyze the global knowledge pattern of monkeypox-related patents and explore current trends and future technical directions in the medical development of monkeypox to inform research and policy. METHODS: A comprehensive study of 1,791 monkeypox-related patents worldwide was conducted using the Derwent patent database by descriptive statistics, social network method and linear regression analysis. RESULTS: Since the 21st century, the number of monkeypox-related patents has increased rapidly, accompanied by increases in collaboration between commercial and academic patentees. Enterprises contributed the most in patent quantity, whereas the initial milestone patent was filed by academia. The core developments of technology related to the monkeypox include biological and chemical medicine. The innovations of vaccines and virus testing lack sufficient patent support in portfolios. CONCLUSIONS: Monkeypox-related therapeutic innovation is geographically limited with strong international intellectual property right barriers though it has increased rapidly in recent years. The transparent licensing of patent knowledge is driven by the merger and acquisition model, and the venture capital, intellectual property and contract research organization model. Currently, the patent thicket phenomenon in the monkeypox field may slow the progress of efforts to combat monkeypox. Enterprises should pay more attention to the sharing of technical knowledge, make full use of drug repurposing strategies, and promote innovation of monkeypox-related technology in hotspots of antivirals (such as tecovirimat, cidofovir, brincidofovir), vaccines (JYNNEOS, ACAM2000), herbal medicine and gene therapy.

Side effects of COVID-19 vaccines in paediatric patients: a review systematic and meta-analysis protocol.

INTRODUCTION: The paediatric population represents a quarter of the world's population, and like adult patients, they have also suffered immeasurably from the SARS-CoV-2 pandemic. Immunisation is an effective strategy for reducing the number of COVID-19 cases. With the advancements in vaccination for younger age groups, parents or guardians have raised doubts and questions about adverse effects and the number of doses required. Therefore, systematic reviews focusing on this population are needed to consolidate evidence that can help in decision-making and clinical practice. This protocol aims to assess the safety of COVID-19 vaccines in paediatric patients and evaluate the correlation between the number of vaccine doses and side effects. METHODS AND ANALYSIS: We will search the PubMed, ClinicalTrials.gov, Web of Science, Embase, CINAHL, Latin American and Caribbean Health Sciences Literature, Scopus and Cochrane databases for randomised and quasi-randomised clinical trials that list the adverse effects of the COVID-19 vaccine and assess its correlation with the number of doses, without any language restrictions. Two reviewers will select the studies according to the inclusion and exclusion criteria, extract data and asses for risk of bias using the Cochrane risk-of-bias tool. The Review Software Manager (RevMan V.5.4.1) will be used to synthesise the data. We will use the Working Group's Grading of Recommendations Assessment, Development and Evaluations to grade the strength of the evidence of the results. ETHICS AND DISSEMINATION: Formal ethical approval is not required as no primary data are collected. This systematic review will be disseminated through a peer-reviewed publication. PROSPERO REGISTRATION NUMBER: CRD42023390077.

Incidence and outcome of COVID-19 following vaccine and hybrid immunity in patients on immunosuppressive therapy: identification of protective post-immunisation anti-RBD antibody levels in a prospective cohort study.

OBJECTIVES: To assess incidence, severity and predictors of COVID-19, including protective post-vaccination levels of antibodies to the receptor-binding domain of SARS-CoV-2 spike protein (anti-RBD), informing further vaccine strategies for patients with immune-mediated inflammatory diseases (IMIDs) on immunosuppressive medication. METHODS: IMIDs on immunosuppressives and healthy controls (HC) receiving SARS-CoV-2 vaccines were included in this prospective observational study. COVID-19 and outcome were registered and anti-RBD antibodies measured 2-5 weeks post-immunisation. RESULTS: Between 15 February 2021 and 15 February 2023, 1729 IMIDs and 350 HC provided blood samples and self-reported COVID-19. The incidence of COVID-19 was 66% in patients and 67% in HC, with re-infection occurring in 12% of patients. Severe COVID-19 was recorded in 22 (2%) patients and no HC. No COVID-19-related deaths occurred. Vaccine-induced immunity gave higher risk of COVID-19 (HR 5.89 (95% CI 4.45 to 7.80)) than hybrid immunity. Post-immunisation anti-RBD levels <6000 binding antibody units/mL were associated with an increased risk of COVID-19 following three (HR 1.37 (95% CI 1.08 to 1.74)) and four doses (HR 1.28 (95% CI 1.02 to 1.62)), and of COVID-19 re-infection (HR 4.47 (95% CI 1.87 to 10.67)). CONCLUSION: Vaccinated patients with IMID have a low risk of severe COVID-19. Hybrid immunity lowers the risk of infection. High post-immunisation anti-RBD levels protect against COVID-19. These results suggest that knowledge on COVID-19 history, and assessment of antibody levels post-immunisation can help individualise vaccination programme series in high-risk individuals. TRIAL REGISTRATION NUMBER: NCT04798625.

Building confidence in the COVID-19 vaccine in a polio-endemic country: strategic communication lessons from Pakistan.

In a health emergency, governments rely on public trust in their policy, and anticipate its compliance to protect health and save lives. Vaccine hesitancy compromises this process when an emergency involves infections. The prevailing discourse on vaccine hesitancy often describes it as a static phenomenon, ignoring its expanse and complexity, and neglecting the exploration of tools to address it. This article diverges from the conventional perspective by explaining the case of Pakistan and its communication strategy for the COVID-19 vaccine. Decades of polio vaccine hesitancy, rooted in the country's fight against terrorism, constitute its history. On the other hand, the first-ever launch of typhoid conjugate vaccine involving 35 million kids during 2019-2021 was a success. Against this backdrop, the country considered vaccine hesitancy as a dynamic phenomenon, interwoven with the social ecology and the responsiveness of the healthcare system. Its communication strategy facilitated those willing to receive the vaccine, while being responsive to the information needs of those still in the decision-making process. In the face of both hesitancy and a scarcity of vaccine doses, the country successfully inoculated nearly 70% (160 million) of its population in just over 1 year. People's perceptions about the COVID-19 vaccine also improved over time. This achievement offers valuable insights and tools for policymakers and strategists focused on the demand side of vaccine programmes. The lessons can significantly contribute to the global discourse on improving vaccine confidence and bolstering global health security.

Modelling the impact of hybrid immunity on future COVID-19 epidemic waves.

BACKGROUND: Since the emergence of SARS-CoV-2 (COVID-19), there have been multiple waves of infection and multiple rounds of vaccination rollouts. Both prior infection and vaccination can prevent future infection and reduce severity of outcomes, combining to form hybrid immunity against COVID-19 at the individual and population level. Here, we explore how different combinations of hybrid immunity affect the size and severity of near-future Omicron waves. METHODS: To investigate the role of hybrid immunity, we use an agent-based model of COVID-19 transmission with waning immunity to simulate outbreaks in populations with varied past attack rates and past vaccine coverages, basing the demographics and past histories on the World Health Organization Western Pacific Region. RESULTS: We find that if the past infection immunity is high but vaccination levels are low, then the secondary outbreak with the same variant can occur within a few months after the first outbreak; meanwhile, high vaccination levels can suppress near-term outbreaks and delay the second wave. Additionally, hybrid immunity has limited impact on future COVID-19 waves with immune-escape variants. CONCLUSIONS: Enhanced understanding of the interplay between infection and vaccine exposure can aid anticipation of future epidemic activity due to current and emergent variants, including the likely impact of responsive vaccine interventions.

Clonal structure and the specificity of vaccine-induced T cell response to SARS-CoV-2 Spike protein.

Adenovirus vaccines, particularly the COVID-19 Ad5-nCoV adenovirus vaccine, have emerged as promising tools in the fight against infectious diseases. In this study, we investigated the structure of the T cell response to the Spike protein of the SARS-CoV-2 virus used in the COVID-19 Ad5-nCoV adenoviral vaccine in a phase 3 clinical trial (NCT04540419). In 69 participants, we collected peripheral blood samples at four time points after vaccination or placebo injection. Sequencing of T cell receptor repertoires from Spike-stimulated T cell cultures at day 14 from 17 vaccinated revealed a more diverse CD4+ T cell repertoire compared to CD8+. Nevertheless, CD8+ clonotypes accounted for more than half of the Spike-specific repertoire. Our longitudinal analysis showed a peak T cell response at day 14, followed by a decline until month 6. Remarkably, multiple T cell clonotypes persisted for at least 6 months after vaccination, as demonstrated by ex vivo stimulation. Examination of CDR3 regions revealed homologous sequences in both CD4+ and CD8+ clonotypes, with major CD8+ clonotypes sharing high similarity with annotated sequences specific for the NYNYLYRLF peptide, suggesting potential immunodominance. In conclusion, our study demonstrates the immunogenicity of the Ad5-nCoV adenoviral vaccine and highlights its ability to induce robust and durable T cell responses. These findings provide valuable insight into the efficacy of the vaccine against COVID-19 and provide critical information for ongoing efforts to control infectious diseases.

Nonstructural barriers to adult vaccination.

Adult vaccination coverage remains low, despite vaccine recommendations, improved access, and reimbursement. Low vaccination coverage and an aging population at higher risk from vaccine-preventable diseases lead to preventable disability and deaths, straining healthcare systems. An Advisory Board meeting was, therefore, held to identify non-structural barriers to adult vaccination and discuss potential solutions to increase uptake. Many non-structural factors can influence vaccine uptake, such as heterogeneity in the population, (fear of) vaccine shortages, incentives, or mandates for vaccination, understanding of disease burden and personal risks, time and opportunity for healthcare providers (HCPs) to discuss and deliver vaccines during general practice or hospital visits, trust in the health system, and education. To address these barriers, push-pull mechanisms are required: to pull patients in for vaccination and to push HCP performance on vaccination delivery. For patients, the focus should be on lifelong prevention and quality of life benefits: personal conversations are needed to increase confidence and knowledge about vaccination, and credible communication is required to build trust in health services and normalize vaccination. For providers, quality measurements are required to prioritize vaccination and ensure opportunities to check vaccination status, discuss and deliver vaccines are not missed. Financial and quality-based incentives may help increase uptake.

What is the context?● As populations age, healthcare systems are increasingly struggling with the burden of adult disease. Multiple vaccines are already recommended for adults throughout their lifetime, and more are coming soon, however, even in countries with subsidized programs, few adults are fully vaccinated, leading to frequent cases of illness, disability, hospitalization, or death, which could have been prevented.What is new?● Experts from Europe and the US joined an Advisory Board meeting to find out what is stopping people from getting vaccinated, particularly when vaccines are free, and how this can be helped in future.● The decision to get vaccinated can vary for different subgroups of the population, and can be influenced by vaccine shortages, rules about vaccination, and understanding the disease severity and need for vaccination. In addition, doctors may not have enough time and opportunity to discuss and provide vaccines during visits or may not feel comfortable raising the issue of vaccination with their patients.● To overcome these issues, both patients and doctors must change. Patients need: greater awareness of how illness impacts overall health and quality of life; better conversations with their doctors to address vaccination concerns; and trustworthy information from health services. For providers, vaccination prioritization should be linked to quality measurements, with collaboration from trusted community members to reinforce the importance of prevention, thus ensuring opportunities are not missed to discuss prevention and vaccinate. Normalizing adult vaccination is important for this.What is the impact?● Taking a patient centered prevention approach will help protect adults and ease the burden of vaccine-preventable disease.

Knowledge-attitude and practice of Anthrax and brucellosis: Implications for zoonotic disease surveillance and control in pastoral communities of Afar and Somali region, Ethiopia.

BACKGROUND: Anthrax and brucellosis are endemic national priority zoonotic diseases in Ethiopia. This study assess the possible factors explaining the current limited information available on animal and human cases in pastoral communities. METHODS: Two questionnaire surveys gathered data from 509 pastoralists and 51 healthcare providers between February and April 2019 in five districts of Afar and the Somali region (SRS). RESULTS: Among the 51 healthcare providers, 25 (49%) and 38 (74.5%) had heard of brucellosis, and anthrax, respectively. Of those, only 3 (12%) and 14 (36.8%) knew the symptoms of brucellosis and Anthrax. None of the Health Extension Workers knew any disease symptoms. Healthcare providers recalled two human cases of brucellosis and 39 cases of Anthrax in the last 12 months, based on symptom-based diagnosis. Pastoralists had a moderate level of knowledge about diseases in their animals, with over half (52.4%; n = 267/509) understanding that animals can transmit diseases to people. Overall, 280 out of 508 (55.1%) and 333 out of 507 (65.7%) pastoralists had heard of brucellosis and Anthrax, respectively. Among the latter, 282 (51.3%) knew at least one preventive measure for Anthrax. However, disease knowledge among women was poor. Despite their knowledge, pastoralists engaged in risky unprotected animal handling, animal product consumption/usage as well as husbandry behaviors exposing them to pathogens and favoring the spread of diseases. They identified Anthrax as the most important zoonosis (47.6%) and as one of top three diseases suspected to cause mortality in their livestock. Pastoralists highlighted lack of vaccine coverage, availability and their timely administration. Both, pastoralists and healthcare providers stated the lack of disease awareness and the unavailability of drugs in the market as important challenges. Health facilities lacked protocols and standard operating procedures for managing zoonotic diseases, and did not have access to laboratory confirmation of pathogens. CONCLUSION: Our study revealed significant under-reporting of Anthrax and brucellosis, and weak prevention and response in humans, mostly associated with poor disease knowledge of healthcare providers. Ability to respond to animal outbreaks was limited by vaccine and drugs availability, timely vaccine administration and the mobility of pastoralists.

Programmatic considerations and evidence gaps for chikungunya vaccine introduction in countries at risk of chikungunya outbreaks: Stakeholder analysis.

Chikungunya can have longstanding effects on health and quality of life. Alongside the recent approval of the world's first chikungunya vaccine by the US Food and Drug Administration in November 2023 and with new chikungunya vaccines in the pipeline, it is important to understand the perspectives of stakeholders before vaccine rollout. Our study aim is to identify key programmatic considerations and gaps in Evidence-to-Recommendation criteria for chikungunya vaccine introduction. We used purposive and snowball sampling to identify global, national, and subnational stakeholders from outbreak prone areas, including Latin America, Asia, and Africa. Semi-structured in-depth interviews were conducted and analysed using qualitative descriptive methods. We found that perspectives varied between tiers of stakeholders and geographies. Unknown disease burden, diagnostics, non-specific disease surveillance, undefined target populations for vaccination, and low disease prioritisation were critical challenges identified by stakeholders that need to be addressed to facilitate rolling out a chikungunya vaccine. Future investments should address these challenges to generate useful evidence for decision-making on new chikungunya vaccine introduction.

COVID-19 Vaccine Injury Compensation Program: Lessons Learned From a Review of 10 Implementing Countries.

National vaccine injury compensation serves as a crucial and significant safety net for individuals affected by government-recommended vaccines during a pandemic, contributing to the community's overall safety. In the Republic of Korea, compensation for adverse events resulting from coronavirus disease 2019 (COVID-19) vaccinations has been provided through the National Vaccine Injury Compensation Program introduced in 1995. However, there have been limitations with these measures during the COVID-19 pandemic owing to strict criteria for substantiating causality between the vaccine and injury, its nontransparent process of determining whether to compensate, and the compensation amount that is not practically calculated. This article reviewed the Vaccine Injury Compensation Programs in 10 major countries to present implications for improving the Korean system. Expanding the scope of national accountability is essential to compensate for the consequences of adhering to national policies during public health crises. Therefore, valuable insight can be obtained from examining the systems in Germany, Japan, and Taiwan, which have implemented more relaxed criteria for determining causality in compensation cases; Thailand's system, which provides the mandatory payment of preliminary compensation for damage caused by vaccination; systems in Germany, France, and Japan, which offer compensation for vaccine injuries from a practical perspective; and systems in France and the United Kingdom, which have a process allowing the assessment records to be shared with the claimants. Furthermore, a dedicated agency for vaccine injury compensation, as seen in France, the United Kingdom, and Australia, is necessary to enhance the efficiency of the Korean system.

Perceptions of dengue risk and acceptability of a dengue vaccine in residents of Puerto Rico.

Dengvaxia is the first dengue vaccine recommended in the United States (U.S.). It is recommended for children aged 9-16 y with laboratory-confirmed previous dengue infection and living in areas where dengue is endemic. We conducted focus groups with parents and in-depth interviews with key informants (i.e. practicing pediatricians, physicians from immunization clinics, university researchers, and school officials) in Puerto Rico (P.R.) to examine acceptability, barriers, and motivators to vaccinate with Dengvaxia. We also carried out informal meetings and semi-structured interviews to evaluate key messages and educational materials with pediatricians and parents. Barriers to vaccination included lack of information, distrust toward new vaccines, vaccine side effects and risks, and high cost of/lack of insurance coverage for laboratory tests and vaccines. Motivators included clear information about the vaccine, a desire to prevent future dengue infections, the experience of a previous dengue infection or awareness of dengue fatality, vaccine and laboratory tests covered by health insurance, availability of rapid test results and vaccine appointments. School officials and parents agreed parents would pay a deductible of $5-20 for Dengvaxia. For vaccine information dissemination, parents preferred an educational campaign through traditional media and social media, and one-on-one counseling of parents by healthcare providers. Education about this vaccine to healthcare providers will help them answer parents' questions. Dengvaxia acceptability in P.R. will increase by addressing motivators and barriers to vaccination and by disseminating vaccine information in plain language through spokespersons from health institutions in P.R.

Who shares fake news on social media? Evidence from vaccines and infertility claims in sub-Saharan Africa.

The widespread dissemination of misinformation on social media is a serious threat to global health. To a large extent, it is still unclear who actually shares health-related misinformation deliberately and accidentally. We conducted a large-scale online survey among 5,307 Facebook users in six sub-Saharan African countries, in which we collected information on sharing of fake news and truth discernment. We estimate the magnitude and determinants of deliberate and accidental sharing of misinformation related to three vaccines (HPV, polio, and COVID-19). In an OLS framework we relate the actual sharing of fake news to several socioeconomic characteristics (age, gender, employment status, education), social media consumption, personality factors and vaccine-related characteristics while controlling for country and vaccine-specific effects. We first show that actual sharing rates of fake news articles are substantially higher than those reported from developed countries and that most of the sharing occurs accidentally. Second, we reveal that the determinants of deliberate vs. accidental sharing differ. While deliberate sharing is related to being older and risk-loving, accidental sharing is associated with being older, male, and high levels of trust in institutions. Lastly, we demonstrate that the determinants of sharing differ by the adopted measure (intentions vs. actual sharing) which underscores the limitations of commonly used intention-based measures to derive insights about actual fake news sharing behaviour.

Minor envelope proteins from GP2a to GP4 contribute to the spread pattern and yield of type 2 PRRSV in MARC-145 cells.

In China, porcine reproductive and respiratory syndrome virus (PRRSV) vaccines are widely used. These vaccines, which contain inactivated and live attenuated vaccines (LAVs), are produced by MARC-145 cells derived from the monkey kidney cell line. However, some PRRSV strains in MARC-145 cells have a low yield. Here, we used two type 2 PRRSV strains (CH-1R and HuN4) to identify the genes responsible for virus yield in MARC-145 cells. Our findings indicate that the two viruses have different spread patterns, which ultimately determine their yield. By replacing the viral envelope genes with a reverse genetics system, we discovered that the minor envelope proteins, from GP2a to GP4, play a crucial role in determining the spread pattern and yield of type 2 PRRSV in MARC-145 cells. The cell-free transmission pattern of type 2 PRRSV appears to be more efficient than the cell-to-cell transmission pattern. Overall, these findings suggest that GP2a to GP4 contributes to the spread pattern and yield of type 2 PRRSV.

PD-L1+ macrophages suppress T cell-mediated anticancer immunity.

Recently, we showed that an autologous DC-based vaccine induces an increase in immunosuppressive PD-L1+ tumor-associated macrophages (TAM) both in the tumor and the tumor draining lymph nodes, thereby blunting the efficacy of therapeutic immunization. Only the combination of the DC vaccine with anti-PD-L1 immune checkpoint inhibition, but not the use of antibodies targeting PD-1 alone, was able to set off CD8+ cytotoxic T lymphocyte (CTL)-mediated tumor suppression in mice. In sum, we delineated a PD-L1 checkpoint blockade-based strategy to avoid TAM-induced T cell exhaustion during DC vaccine therapy.