Margaret Sällberg Chen

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Verified

Margaret verified their affiliation via an institutional email.

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• Professor PhD DDS
• Professor (Full) at Karolinska Institutet

Cross-presentation of cell-associated antigens plays an important role in regulating CD8+ T cell responses to proteins that are not expressed by antigen-presenting cells (APCs). Dendritic cells are the principal cross-presenting APCs in vivo and much progress has been made in elucidating the pathways that allow dendritic cells to capture and proces...

Objectives Intraductal papillary mucinous neoplasms (IPMNs) are pancreatic cysts that can progress to invasive pancreatic cancer. Associations between oncogenesis and oral microbiome alterations have been reported. This study aims to investigate a potential intracystic pancreatic microbiome in a pancreatic cystic neoplasm (PCN) surgery patient coho...

Opportunistic bacteria in apical periodontitis (AP) may pose a risk for systemic dissemination. Mucosal-associated invariant T (MAIT) cells are innate-like T cells with a broad and potent antimicrobial activity important for gut mucosal integrity. It was recently shown that MAIT cells are present in the oral mucosal tissue, but the involvement of M...

Background Immunocompromised individuals are highly susceptible to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. Whether vaccine-induced immunity in these individuals involves oral cavity, a primary site of infection, is presently unknown. Methods Immunocompromised patients (n=404) and healthy controls (n=82) participated...

Objectives Head and neck cancer (HNC) impairs patient immunity and increases susceptibility to oral fungal infections (OFIs). Effectively treating such infections requires accurate identification of the causative pathogens. This study aimed to characterize the mycobiota profile of OFIs in HNC patients undergoing radiation treatment (RT). Materials...

Background Immunocompromised patients with primary and secondary immunodeficiencies have shown impaired responses to SARS-CoV-2 mRNA vaccines, necessitating recommendations for additional booster doses. However, longitudinal data reflecting the real-world impact of such recommendations remains limited. Methods This study represents a two-year foll...

Background/purpose Dysbiosis of oral microbiota has been reported in late stage of chronic hepatitis B (CHB) infection with cirrhosis. CHB is characterized by the constant virus-induced liver injury which may lead to liver cirrhosis and hepatocellular carcinoma (HCC). However, some patients show normal liver function without antiviral treatment, as...

The gut and oral microbiome is altered in people living with HIV (PLWH). While antiretroviral treatment (ART) is pivotal in restoring immune function in PLWH, several studies have identified an association between specific antiretrovirals, particularly integrase inhibitors (INSTI), and weight gain. In our study, we explored the differences in the o...

Introduction Several novel vaccine platforms aim at mucosal immunity in the respiratory tract to block SARS-CoV-2 transmission. Standardized methods for mucosal sample collection and quantification of mucosal antibodies are therefore urgently needed for harmonized comparisons and interpretations across mucosal vaccine trials and real-world data. M...

Background: The gut and oral microbiome is altered in people living with HIV (PLWH). While antiretroviral treatment (ART) is pivotal in restoring immune function in PLWH, several studies have identified an association between specific antiretrovirals, particularly integrase inhibitors (INSTI), and weight gain. In our study, we have explored the dif...

Although mRNA SARS-CoV-2 vaccines are generally safe and effective, in certain immunocompromised individuals they can elicit poor immunogenic responses. Among these individuals, people living with HIV (PLWH) have poor immunogenicity to several oral and parenteral vaccines. As the gut microbiome is known to affect vaccine immunogenicity, we investig...

Background: Patients with chronic lymphocytic leukemia (CLL) are vulnerable to coronavirus disease 2019 (COVID-19) and are at risk of inferior response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination, especially if treated with the first-generation Bruton's tyrosine kinase inhibitor (BTKi) ibrutinib. We aimed to evaluat...

Background: Immunocompromised patients have varying responses to SARS-CoV-2 mRNA vaccination. However, there is limited information available from prospective clinical trial cohorts with respect to long-term immunogenicity-related responses in these patient groups following three or four vaccine doses, and in applicable cases infection. Methods:...

Suboptimal immunity to SARS-CoV-2 mRNA vaccination has frequently been observed in individuals with various immunodeficiencies. Given the increased antibody evasion properties of emerging SARS-CoV-2 subvariants, it is necessary to assess whether other components of adaptive immunity generate resilient and protective responses against infection. We...

Although mRNA SARS-CoV-2 vaccines are generally safe and effective, in certain immunocompromised individuals they can elicit poor immunogenic responses. Among these individuals, people living with HIV (PLWH) have poor immunogenicity to several oral and parenteral vaccines. As the gut microbiome is known to affect vaccine immunogenicity, we investig...

Evolutionary selection for survival and fitness favors bidirectional interactions between dynamic and malleable gut microbes and their hosts. By doing so, dynamic host inter-organ and gut microbiota-organ communications exchange information in an age and sex-dependent manner. An individual’s lifespan is determined by organ decline, “biological agin...

Coevolution of microbiome and immunity at mucosal sites is essential for our health. Whether the oral microbiome, the second largest community after the gut, contributes to the immunogenicity of COVID-19 vaccines is not known. We investigated the baseline oral microbiome in individuals in the COVAXID clinical trial receiving the BNT162b2 mRNA vacci...

Patients with chronic lymphocytic leukemia (CLL) were at high risk early in the COVID-19 pandemic. The Omicron SARS-CoV-2 variant is considered less aggressive, but a significant fatality rate was recently reported from CLL register studies. Here we report on Omicron hybrid immunity in CLL after vaccinations against SARS-CoV-2 followed by disease....

Mucosa-associated invariant T (MAIT) cells are unconventional T cells with innate-like capacity to rapidly respond to microbial infection via MR1-restricted antigen recognition. Emerging evidence indicate that they can also act as rapid sensors of viral infection via innate cytokine activation. However, their possible role in the immune response to...

Oral diseases and associated microbes are a risk factor for systemic diseases and can change the courses of these diseases. To date, epidemiological data on microbial oral infections are scarce, and longitudinal reports are lacking.

Background Previous studies have reported inconsistent results regarding the association between poor dental health and pancreatic cancer risk. This study aimed to assess this association using a well-functioning nationwide dental health registry in Sweden. Methods Information of exposures (dental caries, root canal infection, mild inflammation, a...

Many immunocompromised patients mount suboptimal humoral immunity after SARS-CoV-2 mRNA vaccination. Here, we assessed the single-cell profile of SARS-CoV-2-specific T cells post-mRNA vaccination in healthy individuals and patients with various forms of immunodeficiencies. Impaired vaccine-induced cell-mediated immunity was observed in many immunoc...

Cellular immunotherapies based on T cell receptor (TCR) transfer are promising approaches for the treatment of cancer and chronic viral infections. The discovery of novel receptors is expanding considerably; however, the clinical development of TCR-T cell therapies still lags. Here we provide a pipeline for process development and clinical-scale ma...

Background MAIT cells are innate-like T cells with specialized antimicrobial functions. Circulating MAIT cells are depleted in chronic HIV infection but studies examining this effect in peripheral tissues, such as the female genital tract, are lacking. Methods Flow cytometry was used to investigate circulating MAIT cells in a cohort of HIV+ and HI...

Hepatitis E virus (HEV) is endemic in Europe. However, standardized methods for the surveillance of HEV viremia in the general population are lacking. This study aimed to compare the incidence of HEV among blood donors in two European countries, Germany and Portugal, during the period 2015‐2018. The seasonal distribution of HEV infection, as well a...

Background: Previous research indicates that poor dental health increases risks for certain types of cancers, including esophageal cancer. This study aimed to investigate the association with esophageal cancer using Swedish Dental Health Register. Methods: This is a prospective cohort study. The exposures were dental diagnoses classified into he...

We studied clinical and immunological outcome of Covid-19 in consecutive CLL patients from a well-defined area during month 1–13 of the pandemic. Sixty patients (median age 71 y, range 43–97) were identified. Median CIRS was eight (4–20). Patients had indolent CLL (n = 38), had completed (n = 12) or ongoing therapy (n = 10). Forty-six patients (77%...

Adaptive immune responses have been studied extensively in the course of mRNA vaccination against COVID-19. Considerably fewer studies have assessed the effects on innate immune cells. Here, we characterized NK cells in healthy individuals and immunocompromised patients in the course of an anti-SARS-CoV-2 BNT162b2 mRNA prospective, open-label clini...

Herpes simplex virus type 1 (HSV-1) infects and persists in most of the human population. Interleukin-15 (IL-15) has an important role in the activation of cell-mediated immune responses and acts in complex with IL-15 receptor alpha (IL-15Rα) through cell surface trans-presentation. Here, we have examined the IL-15/IL-15Rα complex response dynamics...

Background Patients with immunocompromised disorders have mainly been excluded from clinical trials of vaccination against COVID-19. Thus, the aim of this prospective clinical trial was to investigate safety and efficacy of BNT162b2 mRNA vaccination in five selected groups of immunocompromised patients and healthy controls. Methods 539 study subje...

Background. Immunocompromised individuals are highly susceptible to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. Whether vaccine-induced immunity in these individuals involves the oral cavity, a primary site of infection, is presently unknown. Methods. Immunocompromised individuals (n=404) and healthy controls (n=82) part...

Background: Patients with immunocompromised disorders have mainly been excluded from clinical trials of vaccination against COVID-19. Thus, the aim of this prospective clinical trial was to investigate the safety and efficacy after two doses of BNT162b2 mRNA vaccination in five selected groups of immunocompromised patients and healthy controls. Met...

Background & Aims Virus-specific T cell dysfunction is a common feature of hepatitis B virus-related hepatocellular carcinoma (HBV-HCC). Conventional T (ConT) cells can be redirected towards viral antigens in HBV-HCC when they express an HBV-specific receptor; however, their efficacy can be impaired by liver-specific physical and metabolic features...

Background Declining humoral immunity in COVID-19 patients and the possibility of reinfection have raised concern. Mucosal immunity, particularly salivary antibodies, may be short-lived although long-term studies are lacking. Methods Using a multiplex bead-based array platform, we investigated antibodies specific to severe acute respiratory syndro...

Pancreatic cancer is the seventh leading cause of cancer-related death worldwide, with a 5 year survival rate as low as 9%. One factor complicating the management of pancreatic cancer is the lack of reliable tools for early diagnosis. While up to 50% of the adult population has been shown to develop precancerous pancreatic cysts, limited and insuff...

Background: Declining humoral immunity in COVID-19 patients and possibility of reinfections has raised concern. Mucosal immunity particularly salivary antibodies could be short-lived. However, long-term studies are sparse. Methods: Using a multiplex bead-based array platform, we investigated antibodies specific to severe acute respiratory syndrome...

Progress in our understanding of MR1-restricted Mucosa-associated Invariant T (MAIT) cells has raised an interest in harnessing these cells for immunotherapy. The innate-like response characteristics, abundance in the blood, donor-unrestricted nature, and tropism for tissues make MAIT cells suitable candidates for adoptive cell transfer therapies....

Emerging research suggests gut microbiome may play a role in pancreatic cancer initiation and progression, but cultivation of the cancer microbiome remains challenging. This pilot study aims to investigate the possibility to cultivate pancreatic microbiome from pancreatic cystic lesions associated with invasive cancer. Intra-operatively acquired pa...

Pancreatic cancer is the seventh leading cause of cancer-related death worldwide, with a 5-year survival rate as low as 9%. One factor complicating the management of pancreatic cancer is the lack of reliable tools for early diagnosis. While up to 50% of the adult population has been shown to develop precancerous pancreatic cysts, limited and insuff...

Objectives Intraductal papillary mucinous neoplasms (IPMNs) are cystic precursor lesions to pancreatic cancer. The presence of oral microbes in pancreatic tissue or cyst fluid has been associated with high-grade dysplasia (HGD) and cancer. The present study aims at investigating if humoral immunity to pancreas-associated oral microbes reflects IPMN...

Chronic infection with viral hepatitis is a major risk factor for liver injury and hepatocellular carcinoma (HCC). One major contributing factor to the chronicity is the dysfunction of virus-specific T cell immunity. T cells engineered to express virus-specific T cell receptors (TCRs) may be a therapeutic option to improve host antiviral responses...

T cell immunotherapy is a concept developed for the treatment of cancer and infectious diseases, based on cytotoxic T lymphocytes to target tumor- or pathogen-specific antigens. Antigen-specificity of the T cell receptors (TCRs) is an important selection criterion in the developmental design of immunotherapy. However, off-target specificity is a po...

Pancreatic cystic neoplasms (PCNs) are a highly prevalent disease of the pancreas. Among PCNs, Intraductal Papillary Mucinous Neoplasms (IPMNs) are common lesions that may progress from low-grade dysplasia (LGD) through high-grade dysplasia (HGD) to invasive cancer. Accurate discrimination of IPMN-associated neoplastic grade is an unmet clinical ne...

Background & aims: Immunosuppressed patients with chronic hepatitis E virus infection (cHEV), who are ineligible or have failed current treatment with off-label ribavirin, are a potential target population for T cell-based therapy. T cell responses are important for viral control. Herein, we aimed to identify human leukocyte antigen (HLA)-A2 restr...

Table 1. Healthy donor demographics Table 2. Statistical significance obtained using Wilcoxon matched‐pairs statistical test for data presented in Figure 5E. p‐values lower than 0.05 are highlighted. Table 3. Antibodies used for in situ microscopic analysis Table 4. Monoclonal antibodies used for flow cytometry Table S5. Primer sequences and anneal...

Peer review correspondence

Mucosa‐associated invariant T (MAIT) cells are unconventional T lymphocytes defined by their innate‐like characteristics and broad antimicrobial responsiveness. Whether MAIT cells are part of the tissue‐resident defense in the oral mucosal barrier is unknown. Here, we found MAIT cells present in the buccal mucosa, with a tendency to cluster near th...

Background & aims: Strategies to develop virus-specific T cells against hepatic viral infections have been hindered by safety concerns. We engineered non-lytic human T cells to suppress replication of hepatitis B virus (HBV) and hepatitis C virus (HCV) without overt hepatotoxicity, and investigated their antiviral activity. Methods: We electropo...

Mucosa-associated invariant T (MAIT) cells are a class of non-classical T lymphocytes defined by their invariant Vα7.2-containing MR1-restricted T cell receptor, as well as high expression of CD161. At present, the characteristics of MAIT cells in the oral mucosa are poorly defined. In this study, we have analyzed buccal biopsies and matched blood...

Therapy with genetically modified autologous T cells has shown great promise in cancer therapy. For an efficient control of hepatitis C virus (HCV) infection, cytotoxic T cells (CTL) are pivotal, but persistence of activated T cells may lead to liver toxicity. Here, anti-HCV T cell receptors (TCRs) recognizing the HCV nonstructural (NS) NS3 or NS5...

Ameloblastoma of the jaws remains the top difficult to treat odontogenic tumour and has a high recurrence rate. New evidence suggests that non-coding RNAs (ncRNAs) play a critical role in tumourgenesis and prognosis of cancer. However, ameloblastoma ncRNA expression data is lacking. Here we present the first report of ameloblastoma ncRNA signatures...

The hepatitis C virus nonstructural (NS) 3/4A and NS5A proteins are major targets for the new direct-acting antiviral compounds. Both viral proteins have been suggested as modulators of the response to the host cell. We have shown that NS3/4A- and NS5A-specific T cell receptors confer different effector functions, and that killing of NS3/4A-express...

The hepatitis B virus (HBV) is a global cause of liver disease. The preventive HBV vaccine has effectively reduced the disease burden. However, an estimated 340 million chronic HBV cases are in need of treatment. Current standard therapy for chronic HBV blocks reversed transcription. As this therapy blocks viral maturation and not viral protein exp...

DNA vaccination has historically failed to raise strong immune responses in humans. Recent delivery techniques such as the gene gun and in vivo electroporation (EP)/electrotransfer (ET) have completely changed the efficiency of DNA vaccines in humans. In vivo EP exerts multiple effects that contribute to its efficiency. The two central factors are...

Background: Previous studies have shown that a calcium (Ca) pre-rinse given before a 228 ppm fluoride (F) rinse greatly increased salivary fluoride. Objectives. The aim of this randomized controlled trial is to examine if Ca pre-rinse could increase the fluoride concentration in the overnight unstimulated saliva after a 905 ppm F-rinse. Materials...

Hepatitis C virus (HCV) is one of the major causes of hepatocellular carcinoma (HCC) around the world. HCV promotes characteristics of cancer stem cells and the infected cells are insensitive to apoptotic signals, which lead to persistent antigen stimulation and T cell exhaustion in the host. In spite of new effective antiviral drugs, new challenge...

Presently the development of new therapies for hepatitis C virus (HCV) is rapidly moving forward. Almost every week new data appear on how direct acting antivirals (DAAs) succeed or fail in clinical trials. Despite the potency of many of the DAA combinations, the effect exerted by ribavirin (RBV) is still needed for an effective therapy in many new...

The hepatitis C virus (HCV) nonstructural (NS) 5A protein has been shown to promote viral persistence by interfering with both innate and adaptive immunity. At the same time, the HCV NS5A protein has been suggested as a target for antiviral therapy. In this study, we performed a detailed characterization of HCV NS5A immunogenicity in wild-type (wt)...

Virus-specific CTL with high levels of functional avidity have been associated with viral clearance in hepatitis C virus (HCV) infection and with enhanced protective immunity. In chronic HCV infection, lack of antiviral CTL is frequently observed. In this study, we aim to investigate novel HCV TCRs that differ in Ag specificity. This involved isola...

Objectives: To examine the fluoride concentration in unstimulated saliva 10 hours after rinsing, comparing different concentrations of calcium lactate as pre-rinse to 905 ppm NaF. Methods: Nine subjects took part in the phase I RCT study. The study was double blind, 3-armed with cross over design to compare the efficacy of test rinse (placebo, 75...

Hepatitis C virus (HCV) is a major cause of severe liver disease, and one major contributing factor is thought to involve a dysfunction of virus-specific T-cells. T-cell receptor (TCR) gene therapy with HCV-specific TCRs would increase the number of effector T-cells to promote virus clearance. We therefore took advantage of HLA-A2 transgenic mice t...

The hepatitis C virus (HCV)-specific T cell response in patients with chronic HCV is dysfunctional. In this study, we aimed at restoring immunological function through therapeutic vaccination in a transgenic mouse model with impaired HCV-specific T cell responses due to a persistent presence of hepatic HCV nonstructural (NS)3/4A Ags. The HCV-specif...

Alphaviral replicon-based vectors induce potent immune responses both when given as viral particles (VREP) or as DNA (DREP). It has been suggested that the strong immune stimulatory effect induced by these types of vectors is mediated by induction of danger signals and activation of innate signalling pathways due to the replicase activity. To inves...

The without a doubt major obstacle for making DNA vaccines a commercial success is delivery. If delivery cannot be made simple, cheap and effective, DNA vaccines may not become a viable option for human use. Numerous clinical trials have confirmed that a standard needle and syringe simply do not do the job, i.e., delivering the DNA payload inside t...

To enhance the efficacy of a therapeutic immunisation strategy against human papillomavirus-induced cervical cancer we evaluated the adjuvant effect of interleukin-12 (IL12) expressed by a Semliki Forest virus vector (SFV) in mice. Depending on the dose and schedule, SFV-IL12 stimulated antigen-specific CTL responses elicited upon immunisation with...

Recombinants based on the attenuated vaccinia virus strains MVA and NYVAC are considered candidate vectors against different human diseases. In this study we have generated and characterized in BALB/c and in transgenic HHD mice the immunogenicity of two attenuated poxvirus vectors expressing in a single locus (TK) the codon optimized HIV-1 genes en...

While virus-infected dendritic cells (DCs) in certain instances have the capacity to activate naive T cells by direct priming, cross-priming by DCs via the uptake of antigens from infected cells has lately been recognized as another important pathway for the induction of antiviral immunity. During cross-priming, danger and stranger signals play imp...

The function of the hepatitis B virus (HBV) precore or HBeAg is largely unknown because it is not required for viral assembly, infection, or replication. However, the HBeAg does appear to play a role in viral persistence. It has been suggested that the HBeAg may promote HBV chronicity by functioning as an immunoregulatory protein. As a model of chr...

A successful vaccine against human RSV (HRSV) is likely to induce a Th1 or a balanced Th1/TH2 cytokine response. We tested a panel of HRSV immunostimulating complexes (ISCOMs) containing different Quillaja saponin fractions (QH-A, QH-C, and 703: a mixture of 70% QH-A and 30% QH-C) with different immunological properties for their capacity of induci...

A unique characteristic of the hepatitis B virus is the production of a secreted form (precore or HBeAg) of the structural nucleocapsid (core or HBcAg). By using T cell receptor (TCR) transgenic (Tg) and TCR x HBc/HBeAg double- and triple-Tg pairs, we demonstrate that HBeAg elicits T cell tolerance, whereas HBcAg is nontolerogenic in this system. I...

Respiratory syncytial virus (RSV) causes severe respiratory diseases in infants and young children. Inappropriate immunity to the virus can lead to disease enhancement upon subsequent infection. In this study, we have characterized the antiviral immunity elicited by the recombinant Semliki Forest virus (SFV) encoding the RSV fusion (F) and attachme...

Replicons based on alphaviruses are emerging as candidate vectors for vaccination and gene therapy purposes. We have reported previously that mice vaccinated with a recombinant Semliki Forest virus (a member of the alphavirus genus) carrying the gene encoding the P815A tumor antigen (rSFV/E-P1A) were protected against a lethal challenge with the P8...