Historically platelets are mostly known for their crucial contribution to hemostasis, but there is growing understanding of their role in inflammation and immunity. The immunomodulatory role of... Show moreHistorically platelets are mostly known for their crucial contribution to hemostasis, but there is growing understanding of their role in inflammation and immunity. The immunomodulatory role of platelets entails interaction with pathogens, but also with immune cells including macrophages and dendritic cells (DCs), to activate adaptive immune responses. In our previous work, we have demonstrated that splenic CD169(+) macrophages scavenge liposomes and collaborate with conventional type 1 DCs (cDC1) to induce expansion of CD8(+) T cells. Here, we show that platelets associate with liposomes and bind to DNGR-1/Clec9a and CD169/Siglec-1 receptors in vitro. In addition, platelets interacted with splenic CD169(+) macrophages and cDC1 and further increased liposome internalization by cDC1. Most importantly, platelet depletion prior to liposomal immunization resulted in significantly diminished antigen-specific CD8(+) T cell responses, but not germinal center B cell responses. Previously, complement C3 was shown to be essential for platelet-mediated CD8(+) T cell activation during bacterial infection. However, after liposomal vaccination CD8(+) T cell priming was not dependent on complement C3. While DCs from platelet-deficient mice exhibited unaltered maturation status, they did express lower levels of CCR7. In addition, in the absence of platelets, CCL5 plasma levels were significantly reduced. Overall, our findings demonstrate that platelets engage in a cross-talk with CD169(+) macrophages and cDC1 and emphasize the importance of platelets in induction of CD8(+) T cell responses in the context of liposomal vaccination. Show less
Arend, B.W.H. van der; Bloemhof, M.M.; Schoor, A.G. van der; Zwet, E.W. van; Terwindt, G.M. 2023
BackgroundThis longitudinal cohort study aimed to investigate changes in migraine-related outcomes following COVID-19 infection and vaccination.MethodsWe identified 547 clinically diagnosed... Show moreBackgroundThis longitudinal cohort study aimed to investigate changes in migraine-related outcomes following COVID-19 infection and vaccination.MethodsWe identified 547 clinically diagnosed migraine patients from the Leiden Headache Center who kept a headache E-diary during the COVID-19 pandemic (February 2020 to August 2022). We sent a questionnaire to register their COVID-19 infection and/or vaccination dates. After applying inclusion criteria, n = 59 participants could be included in the infection analysis and n = 147 could be included in the vaccination analysis. Primary outcome was the change in monthly migraine days (MMD) between 1 month prior and 1 month post COVID-19 infection or vaccination. Secondary outcome variables were change in monthly headache days (MHD) and monthly acute medication days (MAMD).ResultsVaccination against COVID-19 was associated with an increase in MMD (1.06; 95% confidence interval [CI] = 0.57–1.55; p < 0.001), MHD (1.52; 95% CI = 0.91–2.14; p < 0.001) and MAMD (0.72; 95% CI = 0.33–1.12; p < 0.001) in the first month post-vaccination. COVID-19 infection solely increased the number of MAMD (1.11; 95% CI = 0.10–1.62; p < 0.027), but no statistically significant differences in MMD or MHD were observed.ConclusionsOur findings imply that vaccination against COVID-19 is associated with an increase in migraine, indicating a possible role of inflammatory mediators in migraine pathophysiology. Show less
Background: Nursing home (NH) staff and residents have been prioritized to receive COVID-19 vaccinations. However, NH staff have been hesitant. This study explored what strategies were used to... Show moreBackground: Nursing home (NH) staff and residents have been prioritized to receive COVID-19 vaccinations. However, NH staff have been hesitant. This study explored what strategies were used to overcome this hesitancy and which of these were found to be important by NH staff to increase their willingness to take a COVID-19 vaccine. Methods: This study employed a sequential exploratory qualitative design. The COVID-19 MINUTES study aimed to describe the challenges presented by, responses to, and impact of the COVID-19 pandemic in NHs. The minutes of COVID-19 outbreak teams (COTs) in Dutch long-term care organizations (n = 41) were collected and coded using content analysis. Textual units from December 2020 to April 2021 that regarded strategies to increase staff's vaccination willingness (n = 67) were selected. Subsequently, to validate these data, two panels of NH healthcare workers (HCWs) and policy workers (PWs) (n = 8) selected, discussed, and ranked the strategies that they found to be important using a modified nominal group technique. Results: The strategies described in the minutes included financial reimbursements, personal contact, story sharing, logistics support, role models, visual information, and written information. Except for financial reimbursement, all these strategies were considered important or very important by the panel participants. Some organizations combined multiple strategies. Conclusion: The strategies that were found important in combination may be used more broadly and should be developed further with the involvement of HCWs. Show less
Background: The new types of mRNA-containing lipid nanoparticle vaccines BNT162b2 and mRNA-1273 and the adenovirus-based vaccine AZD1222 were developed against SARS-CoV-2 and code for its spike (S)... Show moreBackground: The new types of mRNA-containing lipid nanoparticle vaccines BNT162b2 and mRNA-1273 and the adenovirus-based vaccine AZD1222 were developed against SARS-CoV-2 and code for its spike (S) protein. Several studies have investigated short-term antibody (Ab) responses after vaccination. Objective: However, the impact of these new vaccine formats with unclear effects on the long-term Ab response - including isotype, subclass, and their type of Fc glycosylation - is less explored. Methods: Here, we analyzed anti-S Ab responses in blood serum and the saliva of SARS-CoV-2 naive and non-hospitalized pre-infected subjects upon two vaccinations with different mRNA- and adenovirus-based vaccine combinations up to day 270. Results: We show that the initially high mRNA vaccine-induced blood and salivary anti-S IgG levels, particularly IgG1, markedly decrease over time and approach the lower levels induced with the adenovirus-based vaccine. All three vaccines induced, contrary to the short-term anti-S IgG1 response with high sialylation and galactosylation levels, a long-term anti-S IgG1 response that was characterized by low sialylation and galactosylation with the latter being even below the corresponding total IgG1 galactosylation level. Instead, the mRNA, but not the adenovirus-based vaccines induced long-term IgG4 responses - the IgG subclass with inhibitory effector functions. Furthermore, salivary anti-S IgA levels were lower and decreased faster in naive as compared to pre-infected vaccinees. Predictively, age correlated with lower long-term anti-S IgG titers for the mRNA vaccines. Furthermore, higher total IgG1 galactosylation, sialylation, and bisection levels correlated with higher long-term anti-S IgG1 sialylation, galactosylation, and bisection levels, respectively, for all vaccine combinations. Conclusion: In summary, the study suggests a comparable "adjuvant" potential of the newly developed vaccines on the anti-S IgG Fc glycosylation, as reflected in relatively low long-term anti-S IgG1 galactosylation levels generated by the long-lived plasma cell pool, whose induction might be driven by a recently described T-H1-driven B cell response for all three vaccines. Instead, repeated immunization of naive individuals with the mRNA vaccines increased the proportion of the IgG4 subclass over time which might influence the long-term Ab effector functions. Taken together, these data shed light on these novel vaccine formats and might have potential implications for their long-term efficacy. Show less
Simple Summary Photodynamic therapy (PDT) by means of a photosensitizer is a clinically used therapeutic treatment in a variety of cancers. To further improve the anti-cancer efficiency of PDT,... Show moreSimple Summary Photodynamic therapy (PDT) by means of a photosensitizer is a clinically used therapeutic treatment in a variety of cancers. To further improve the anti-cancer efficiency of PDT, combination therapy with immune agents is a promising option. In this study, we used a viral vaccine as the immune therapeutic partner for PDT. We studied the biological properties of single and combined modalities. Our research suggests that combination therapy enhances innate and humoral immunity, improved survival, and generated a long-term memory capacity in the MC-38 murine colorectal tumor model to prevent a recurrence. Photodynamic therapy (PDT), which combines light and oxygen with a photosensitizer to induce reactive oxygen species (ROS)-mediated killing of primary tumor cells, benefits from non-invasive properties and its negligible toxicity to surrounding healthy tissues. In this study, we have shown that the second-generation photosensitizer FOSCAN can be internalized by tumor cells and effectively induce tumor cell death when exposed to laser irradiation in vitro. In addition, these dying tumor cells can be phagocytosed by dendritic cells and lead to their activation and maturation as assessed by in vitro co-culture models. While PDT induces immunogenic tumor cell apoptosis, its application for the treatment of tumors located in deep tissues and advanced malignancies has been limited. In this study, we demonstrate that hepatitis B core virus-like particles (HBc VLPs) can serve as a vaccine to enhance PDT-induced anti-cancer immunity by priming humoral immune responses and inducing CD8(+) T cell responses. The combination of PDT and HBc VLPs increased the survival rate of MC-38 tumor-bearing mice to 55%, compared to 33% in PDT alone and no tumor-free mice in vaccine alone. Moreover, the combination effectively prevented tumor recurrence in vivo through enhanced immune memory T cells after therapy. Therefore, as both are clinically approved techniques, this combination provides a promising strategy for cancer therapy. Show less
Gordon, A.L.; Achterberg, W.P.; Delden, J.J.M. van 2022
The COVID-19 pandemic has particularly adversely affected older people with frailty and functional dependency. Essential regular contact with care staff has been evidenced as an important source of... Show moreThe COVID-19 pandemic has particularly adversely affected older people with frailty and functional dependency. Essential regular contact with care staff has been evidenced as an important source of infection for this group. Vaccinating care staff can reduce the incidence, duration and severity of infection, preventing onward transmission to older people and minimising the harm associated with discontinuity caused by staff absence. Voluntary vaccination programmes for staff are more likely to be effective when associated with information and education, community engagement and financial incentives, but programmes using all of these approaches have failed to establish consistently high vaccination rates among care staff during the pandemic. Mandatory vaccination, proposed as a solution in some countries, can increase vaccination rates. It is only ethical if a vaccine is effective and cost-effective, the risk associated with vaccinating care workers is proportionate to the risk reduction achieved through vaccination, and where all efforts to encourage voluntary vaccination have been exhausted. Even when these conditions have been met, careful attention is required to ensure that the penalties associated with conscientious objection are proportionate and to ensure that implementation is equitable in a way that does not disadvantage particular groups of staff. Show less
Objectives Perform a systematic literature review (SLR) on risk and prognosis of SARS-CoV-2 infection and vaccination against SARS-CoV-2 in patients with rheumatic and musculoskeletal diseases ... Show moreObjectives Perform a systematic literature review (SLR) on risk and prognosis of SARS-CoV-2 infection and vaccination against SARS-CoV-2 in patients with rheumatic and musculoskeletal diseases (RMDs). Methods Literature was searched up to 31 May 2021, including (randomised) controlled trials and observational studies with patients with RMD. Pending quality assessment, data extraction was performed and risk of bias (RoB) was assessed. Quality assessment required provision of (1) an appropriate COVID-19 case definition, and (2a) a base incidence (for incidence data) or (2b) a comparator, >10 cases with the outcome and risk estimates minimally adjusted for age, sex and comorbidities (for risk factor data). Results Of 5165 records, 208 were included, of which 90 passed quality assessment and data were extracted for incidence (n=42), risk factor (n=42) or vaccination (n=14). Most studies had unclear/high RoB. Generally, patients with RMDs do not face more risk of contracting SARS-CoV-2 (n=26 studies) or worse prognosis of COVID-19 (n=14) than individuals without RMDs. No consistent differences in risk of developing (severe) COVID-19 were found between different RMDs (n=19). Disease activity is associated with worse COVID-19 prognosis (n=2), possibly explaining the increased risk seen for glucocorticoid use (n=13). Rituximab is associated with worse COVID-19 prognosis (n=7) and possibly Janus kinase inhibitors (n=3). Vaccination is generally immunogenic, though antibody responses are lower than in controls. Vaccine immunogenicity is negatively associated with older age, rituximab and mycophenolate. Conclusion This SLR informed the July 2021 update of the European Alliance of Associations for Rheumatology recommendations for the management of RMDs in the context of SARS-CoV-2. Show less
Khatri, I.; Diks, A.M.; Akker, E.B. van den; Oosten, L.E.M.; Zwaginga, J.J.; Reinders, M.J.T.; ... ; Berkowska, M.A. 2021
To mount an adequate immune response against pathogens, stepwise mutation and selection processes are crucial functions of the adaptive immune system. To better characterize a successful... Show moreTo mount an adequate immune response against pathogens, stepwise mutation and selection processes are crucial functions of the adaptive immune system. To better characterize a successful vaccination response, we performed longitudinal (days 0, 5, 7, 10, and 14 after Boostrix vaccination) analysis of the single-cell transcriptome as well as the B-cell receptor (BCR) repertoire (scBCR-rep) in plasma cells of an immunized donor and compared it with baseline B-cell characteristics as well as flow cytometry findings. Based on the flow cytometry knowledge and literature findings, we discriminated individual B-cell subsets in the transcriptomics data and traced over-time maturation of plasmablasts/plasma cells (PB/PCs) and identified the pathways associated with the plasma cell maturation. We observed that the repertoire in PB/PCs differed from the baseline B-cell repertoire e.g., regarding expansion of unique clones in post-vaccination visits, high usage of IGHG1 in expanded clones, increased class-switching events post-vaccination represented by clonotypes spanning multiple IGHC classes and positive selection of CDR3 sequences over time. Importantly, the Variable gene family-based clustering of BCRs represented a similar measure as the gene-based clustering, but certainly improved the clustering of BCRs, as BCRs from duplicated Variable gene families could be clustered together. Finally, we developed a query tool to dissect the immune response to the components of the Boostrix vaccine. Using this tool, we could identify the BCRs related to anti-tetanus and anti-pertussis toxoid BCRs. Collectively, we developed a bioinformatic workflow which allows description of the key features of an ongoing (longitudinal) immune response, such as activation of PB/PCs, Ig class switching, somatic hypermutation, and clonal expansion, all of which are hallmarks of antigen exposure, followed by mutation & selection processes. Show less
Lammers-van der Holst, H.M.; Lammers, G.J.; Horst, G.T.J. van der; Chaves, I.; Vries, R.D. de; GeurtsvanKessel, C.H.; ... ; Kuy, H.M. van der 2021
This protocol describes an innovative study to investigate the relationship between sleep, shift work and the immune response to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2;... Show moreThis protocol describes an innovative study to investigate the relationship between sleep, shift work and the immune response to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2; coronavirus disease 2019 [COVID-19]) vaccination. As the COVID-19 pandemic is a global crisis with devastating health, social and economic impacts, there is a pressing need for effective vaccination programmes. Previous influenza and hepatitis vaccination studies suggest that lack of sleep can negatively alter immune responsiveness, while circadian misalignment most likely may also play an important role in the immune response to vaccination. Our present study will be the first to address this question in actual shift workers and in relation to COVID-19 vaccination. We hypothesise that the occurrence of recent night shifts and diminished sleep will negatively alter the immune response to vaccination in shift workers compared to dayworkers. We aim to recruit 50 shift workers and 50 dayworkers. Participants will receive an mRNA-based vaccination, through the Dutch vaccination programme. To assess immune responsiveness, blood will be drawn at baseline (before first vaccination), 10 days after first vaccination, the day prior to the second vaccination; and 28 days, 6 and 12 months after the second vaccination. Actigraphy and daily sleep e-diaries will be implemented for 7 days around each vaccination to assess sleep. The Pittsburgh Sleep Quality Index will be used to monitor sleep in the long term. Optimising the efficacy of the COVID-19 vaccines is of outmost importance and results of this study could provide insights to develop sleep and circadian-based interventions to enhance vaccination immunity, and thereby improve global health. Show less
Ng, X. le; Betzler, B.K.; Testi, I.; Ho, S.L.; Tien, M.; Ngo, W.K.; ... ; Agrawal, R. 2021
Purpose The COVID-19 pandemic has galvanized the development of new vaccines at an unprecedented pace. Since the widespread implementation of vaccination campaigns, reports of ocular adverse... Show morePurpose The COVID-19 pandemic has galvanized the development of new vaccines at an unprecedented pace. Since the widespread implementation of vaccination campaigns, reports of ocular adverse effects after COVID-19 vaccinations have emerged. This review summarizes ocular adverse effects possibly associated with COVID-19 vaccination, and discusses their clinical characteristics and management. Methods Narrative Literature Review. Results Ocular adverse effects of COVID-19 vaccinations include facial nerve palsy, abducens nerve palsy, acute macular neuroretinopathy, central serous retinopathy, thrombosis, uveitis, multiple evanescent white dot syndrome, Vogt-Koyanagi-Harada disease reactivation, and new-onset Graves' Disease. Studies in current literature are primarily retrospective case series or isolated case reports - these are inherently weak in establishing association or causality. Nevertheless, the described presentations resemble the reported ocular manifestations of the COVID-19 disease itself. Hence, we hypothesize that the human body's immune response to COVID-19 vaccinations may be involved in the pathogenesis of the ocular adverse effects post-COVID-19 vaccination. Conclusion Ophthalmologists and generalists should be aware of the possible, albeit rare, ocular adverse effects after COVID-19 vaccination. Show less
Background: Effector functions of IgG Abs are regulated by their Fc N-glycosylation pattern. IgG Fc glycans that lack galactose and terminal sialic acid residues correlate with the severity of... Show moreBackground: Effector functions of IgG Abs are regulated by their Fc N-glycosylation pattern. IgG Fc glycans that lack galactose and terminal sialic acid residues correlate with the severity of inflammatory (auto)immune disorders and have also been linked to protection against viral infection and discussed in the context of vaccine-induced protection. In contrast, sialylated IgG Abs have shown immunosuppressive effects.Objective: We sought to investigate IgG glycosylation programming during the germinal center (GC) reaction following immunization of mice with a foreign protein antigen and different adjuvants.Methods: Mice were analyzed for GC T-cell, B-cell, and plasma cell responses, as well as for antigen-specific serum IgG subclass titers and Fc glycosylation patterns.Results: Different adjuvants induce distinct IgG(+) GC B-cell responses with specific transcriptomes and expression levels of the alpha 2,6-sialyltransferase responsible for IgG sialylation that correspond to distinct serum IgG Fc glycosylation patterns. Low IgG Fc sialylation programming in GC B cells was overall highly dependent on the Foxp3(-) follicular helper T (TFH) cell-inducing cytokine IL-6, here in particular induced by water-inoil adjuvants and Mycobacterium tuberculosis. Furthermore, low IgG Fc sialylation programming was dependent on adjuvants that induced IL-27 receptor-dependent IFN-gamma(+) TFH1 cells, IL-6/IL-23-dependent IL-17A(+) T-FH17 cells, and high ratios of TFH cells to Foxp31 follicular regulatory T cells. Here, the 2 latter were dependent on M tuberculosis and its cord factor.Conclusion: This study's findings regarding adjuvant-dependent GC responses and IgG glycosylation programming may aid in the development of novel vaccination strategies to induce IgG Abs with both high affinity and defined Fc glycosylation patterns in the GC. Show less
Grein, I.H.R.; Pinto, N.F.; Lobo, A.; Groot, N.; Sztajnbok, F.; Silva, C.A.A. da; ... ; Pileggi, G. 2020
ObjectiveThis study aimed to assess the safety and immunogenicity of the quadrivalent human papillomavirus (qHPV) vaccination in childhood-onset systemic lupus erythematosus (cSLE) patients... Show moreObjectiveThis study aimed to assess the safety and immunogenicity of the quadrivalent human papillomavirus (qHPV) vaccination in childhood-onset systemic lupus erythematosus (cSLE) patients.MethodsVolunteer cSLE patients aged 9-20 years and healthy controls (HC) were enrolled to receive a two- or three-dose qHPV vaccination schedule from March 2014 to March 2016. Study visits were performed before the first dose, one month after the second and third doses and one year after the first dose. In each study visit, disease activity and adverse events following vaccination were analyzed, and a serum sample was collected for testing antibody concentrations. Participant recruitment was conducted in 15 Brazilian paediatric rheumatology units. Of the 256 cSLE patients included, 210 completed the two- or three-dose schedules; 15 had previously received one dose, and 18 had received two doses of the vaccine. The analysis was based on intention-to-treat so that participants who did not complete the entire study protocol were also included.ResultsNo severe adverse events were related to the vaccination. Disease activity was generally low and remained stable or even improved. The HC presented 100% seropositivity to HPV16 and HPV18, whereas the two- and three-dose cSLE groups presented 93% and 83% versus 97% and 91%, respectively. One year after the first dose, seropositivity of the three-dose cSLE group was 91% to HPV16 and 84% to HPV18.ConclusionsHPV vaccination in cSLE patients is safe and immunogenic. Since the seropositivity to HPV16 and HPV18 was higher for the three-dose schedule group, this regimen should be recommended for cSLE patients. Show less
Gracht, E.T.I. van der; Schoonderwoerd, M.J.; Duikeren, S. van; Yilmaz, A.N.; Behr, F.M.; Colston, J.M.; ... ; Arens, R. 2020
Background Adenoviral vectors emerged as important platforms for cancer immunotherapy. Vaccination with adenoviral vectors is promising in this respect, however, their specific mechanisms of action... Show moreBackground Adenoviral vectors emerged as important platforms for cancer immunotherapy. Vaccination with adenoviral vectors is promising in this respect, however, their specific mechanisms of action are not fully understood. Here, we assessed the development and maintenance of vaccine-induced tumor-specific CD8(+) T cells elicited upon immunization with adenoviral vectors. Methods Adenoviral vaccine vectors encoding the full-length E7 protein from human papilloma virus (HPV) or the immunodominant epitope from E7 were generated, and mice were immunized intravenously with different quantities (10(7), 10(8) or 10(9) infectious units). The magnitude, kinetics and tumor protection capacity of the induced vaccine-specific T cell responses were evaluated. Results The adenoviral vaccines elicited inflationary E7-specific memory CD8(+) T cell responses in a dose-dependent manner. The magnitude of these vaccine-specific CD8(+) T cells in the circulation related to the development of E7-specific CD8(+) tissue-resident memory T (T-RM) cells, which were maintained for months in multiple tissues after vaccination. The vaccine-specific CD8(+) T cell responses conferred long-term protection against HPV-induced carcinomas in the skin and liver, and this protection required the induction and accumulation of CD8(+) T-RM cells. Moreover, the formation of CD8(+) T-RM cells could be enhanced by temporal targeting CD80/CD86 costimulatory interactions via CTLA-4 blockade early after immunization. Conclusions Together, these data show that adenoviral vector-induced CD8(+) T cell inflation promotes protective T-RM cell populations, and this can be enhanced by targeting CTLA-4. Show less
Nejad, E.B.; Labrie, C.; Abdulrahman, Z.; Elsas, M.J. van; Rademaker, E.; Kleinovink, J.W.; ... ; Burg, S.H. van der 2020
Background Immunotherapy of cancer is successful but tumor regression often is incomplete and followed by escape. Understanding the mechanisms underlying this acquired resistance will aid the... Show moreBackground Immunotherapy of cancer is successful but tumor regression often is incomplete and followed by escape. Understanding the mechanisms underlying this acquired resistance will aid the development of more effective treatments. Methods We exploited a mouse model where tumor-specific therapeutic vaccination results in tumor regression, followed by local recurrence and resistance. In depth studies on systemic, local and tumor intrinsic changes were performed with flow and mass cytometry, immunohistochemistry, transcriptomics and several perturbation studies with inhibitors or agonistic antibodies in mice. Main findings were recapitulated in vaccinated patients. Results Full tumor regression and cure of tumor-bearing mice is dependent on the magnitude of the vaccine-induced T-cell response. Recurrence of tumors did not involve classical immune escape mechanisms, such as antigen-presentation alterations, immune checkpoint expression, resistance to killing or local immune suppression. However, the recurrent tumors displayed a changed transcriptome with alterations in p53, tumor necrosis factor-alpha and transforming growth factor-beta signaling pathways and they became immunologically cold. Remarkably, ex vivo cell-sorted recurrent tumors, directly reinjected in naive hosts retained their resistance to vaccination despite a strong infiltration with tumor-specific CD8(+)T cells, similar to that of vaccine-responsive tumors. The influx of inflammatory mature myeloid effector cells in the resistant tumors, however, was impaired and this turned out to be the underlying mechanisms as restoration of inflammatory myeloid cell infiltration reinstated the sensitivity of these refractory tumors to vaccination. Notably, impaired myeloid cell infiltration after vaccination was also associated with vaccine resistance in patients. Conclusion An immunotherapy-induced disability of tumor cells to attract innate myeloid effector cells formed a major mechanism underlying immune escape and acquired resistance. These data not only stresses the importance of myeloid effector cells during immunotherapy but also demands for new studies to harness their tumoricidal activities. Show less
An outbreak of measles in the Netherlands in 2013-2014 provided an opportunity to assess the effect of MMR vaccination on severity and infectiousness of measles. Measles is notifiable in the... Show moreAn outbreak of measles in the Netherlands in 2013-2014 provided an opportunity to assess the effect of MMR vaccination on severity and infectiousness of measles. Measles is notifiable in the Netherlands. We used information on vaccination, hospitalisation, complications, and most likely source(s) of infection from cases notified during the outbreak. When a case was indicated as a likely source for at least one other notified case, we defined it as infectious. We estimated the age-adjusted effect of vaccination on severity and infectiousness with logistic regression. Of 2676 notified cases, 2539 (94.9%) were unvaccinated, 121 (4.5%) were once-vaccinated and 16 (0.6%) were at least twice-vaccinated; 328 (12.3%) cases were reported to have complications and 172 (6.4%) cases were hospitalised. Measles in twice-vaccinated cases led less often to complications and/or hospitalisation than measles in unvaccinated cases (0% and 14.5%, respectively, aOR 0.1 (95% CI 0-0.89), P = 0.03). Of unvaccinated, once-vaccinated and twice-vaccinated cases, respectively, 194 (7.6%), seven (5.1%) and 0 (0%) were infectious. These differences were not statistically significant (P > 0.05). Our findings suggest a protective effect of vaccination on the occurrence of complications and/or hospitalisation as a result of measles and support the WHO recommendation of a two-dose MMR vaccination schedule. Show less
Hos, B.J.; Camps, M.G.M.; Bulk, J. van den; Tondini, E.; Ende, T.C. van den; Ruano, D.; ... ; Ossendorp, F. 2020
The murine MC-38 colorectal cancer model is a commonly used model for cancer with high mutational burden, which is sensitive for immune checkpoint immunotherapy. We set out to analyze endogenous... Show moreThe murine MC-38 colorectal cancer model is a commonly used model for cancer with high mutational burden, which is sensitive for immune checkpoint immunotherapy. We set out to analyze endogenous CD8(+) T cell responses to MC-38 neo-antigens in tumor-bearing mice and after anti-PD-L1 checkpoint therapy. Through combination of whole-exome sequencing analysis with mass spectrometry of MHC class I eluted peptides we could identify eight candidate epitopes. Of these, a neo-epitope encoded by a point-mutation in the sequence of the ribosomal protein L18 (Rpl18) strongly dominated the CD8(+) T cell response to our MC-38 cell-line in comparison to a previously described neo-epitope in the Adpgk protein. Therapeutic vaccination with synthetic peptides induced CD8(+) T cell responses against the mutated Rpl18 epitope, which controlled tumor growth in vivo. This immunologically dominant response to mutated Rpl18 is of great importance in the development and optimization of immunotherapeutic strategies with the MC-38 tumor model. Show less
Lau, S.P.; Montfoort, N. van; Kinderman, P.; Lukkes, M.; Klaase, L.; Nimwegen, M. van; ... ; Eijck, C.H.J. van 2020
Background Pancreatic ductal adenocarcinoma (PDAC) is notoriously resistant to treatment including checkpoint-blockade immunotherapy. We hypothesized that a bimodal treatment approach consisting of... Show moreBackground Pancreatic ductal adenocarcinoma (PDAC) is notoriously resistant to treatment including checkpoint-blockade immunotherapy. We hypothesized that a bimodal treatment approach consisting of dendritic cell (DC) vaccination to prime tumor-specific T cells, and a strategy to reprogram the desmoplastic tumor microenvironment (TME) would be needed to break tolerance to these pancreatic cancers. As a proof-of-concept, we investigated the efficacy of combined DC vaccination with CD40-agonistic antibodies in a poorly immunogenic murine model of PDAC. Based on the rationale that mesothelioma and pancreatic cancer share a number of tumor associated antigens, the DCs were loaded with either pancreatic or mesothelioma tumor lysates. Methods Immune-competent mice with subcutaneously or orthotopically growing KrasG12D/+;Trp53R172H/+;Pdx-1-Cre (KPC) PDAC tumors were vaccinated with syngeneic bone marrow-derived DCs loaded with either pancreatic cancer (KPC) or mesothelioma (AE17) lysate and consequently treated with FGK45 (CD40 agonist). Tumor progression was monitored and immune responses in TME and lymphoid organs were analyzed using multicolor flow cytometry and NanoString analyzes. Results Mesothelioma-lysate loaded DCs generated cross-reactive tumor-antigen-specific T-cell responses to pancreatic cancer and induced delayed tumor outgrowth when provided as prophylactic vaccine. In established disease, combination with stimulating CD40 antibody was necessary to improve survival, while anti-CD40 alone was ineffective. Extensive analysis of the TME showed that anti-CD40 monotherapy did improve CD8 +T cell infiltration, but these essential effector cells displayed hallmarks of exhaustion, including PD-1, TIM-3 and NKG2A. Combination therapy induced a strong change in tumor transcriptome and mitigated the expression of inhibitory markers on CD8 +T cells. Conclusion These results demonstrate the potency of DC therapy in combination with CD40-stimulation for the treatment of pancreatic cancer and provide directions for near future clinical trials. Show less
