Single-cell analysis of memory B cells from top neutralizers reveals multiple sites of vulnerability within HCMV Trimer and Pentamer.

Human cytomegalovirus (HCMV) can cause severe diseases in fetuses, newborns, and immunocompromised individuals. Currently, no vaccines are approved, and treatment options are limited. Here, we analyzed the human B cell response of four HCMV top neutralizers from a cohort of 9,000 individuals. By single-cell analyses of memory B cells targeting the pentameric and trimeric HCMV surface complexes, we identified vulnerable sites on the shared gH/gL subunits as well as complex-specific subunits UL128/130/131A and gO. Using high-resolution cryogenic electron microscopy, we revealed the structural basis of the neutralization mechanisms of antibodies targeting various binding sites. Moreover, we identified highly potent antibodies that neutralized a broad spectrum of HCMV strains, including primary clinical isolates, that outperform known antibodies used in clinical trials. Our study provides a deep understanding of the mechanisms of HCMV neutralization and identifies promising antibody candidates to prevent and treat HCMV infection.

Differential interferon-α subtype induced immune signatures are associated with suppression of SARS-CoV-2 infection.

Type I interferons (IFN-I) exert pleiotropic biological effects during viral infections, balancing virus control versus immune-mediated pathologies, and have been successfully employed for the treatment of viral diseases. Humans express 12 IFN-alpha (α) subtypes, which activate downstream signaling cascades and result in distinct patterns of immune responses and differential antiviral responses. Inborn errors in IFN-I immunity and the presence of anti-IFN autoantibodies account for very severe courses of COVID-19; therefore, early administration of IFN-I may be protective against life-threatening disease. Here we comprehensively analyzed the antiviral activity of all IFNα subtypes against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to identify the underlying immune signatures and explore their therapeutic potential. Prophylaxis of primary human airway epithelial cells (hAEC) with different IFNα subtypes during SARS-CoV-2 infection uncovered distinct functional classes with high, intermediate, and low antiviral IFNs. In particular, IFNα5 showed superior antiviral activity against SARS-CoV-2 infection in vitro and in SARS-CoV-2-infected mice in vivo. Dose dependency studies further displayed additive effects upon coadministration with the broad antiviral drug remdesivir in cell culture. Transcriptomic analysis of IFN-treated hAEC revealed different transcriptional signatures, uncovering distinct, intersecting, and prototypical genes of individual IFNα subtypes. Global proteomic analyses systematically assessed the abundance of specific antiviral key effector molecules which are involved in IFN-I signaling pathways, negative regulation of viral processes, and immune effector processes for the potent antiviral IFNα5. Taken together, our data provide a systemic, multimodular definition of antiviral host responses mediated by defined IFN-I. This knowledge will support the development of novel therapeutic approaches against SARS-CoV-2.

Comparison of post-COVID-19 symptoms in patients infected with the SARS-CoV-2 variants delta and omicron-results of the Cross-Sectoral Platform of the German National Pandemic Cohort Network (NAPKON-SUEP).

PURPOSE: The influence of new SARS-CoV-2 variants on the post-COVID-19 condition (PCC) remains unanswered. Therefore, we examined the prevalence and predictors of PCC-related symptoms in patients infected with the SARS-CoV-2 variants delta or omicron. METHODS: We compared prevalences and risk factors of acute and PCC-related symptoms three months after primary infection (3MFU) between delta- and omicron-infected patients from the Cross-Sectoral Platform of the German National Pandemic Cohort Network. Health-related quality of life (HrQoL) was determined by the EQ-5D-5L index score and trend groups were calculated to describe changes of HrQoL between different time points. RESULTS: We considered 758 patients for our analysis (delta: n = 341; omicron: n = 417). Compared with omicron patients, delta patients had a similar prevalence of PCC at the 3MFU (p = 0.354), whereby fatigue occurred most frequently (n = 256, 34%). HrQoL was comparable between the groups with the lowest EQ-5D-5L index score (0.75, 95% CI 0.73-0.78) at disease onset. While most patients (69%, n = 348) never showed a declined HrQoL, it deteriorated substantially in 37 patients (7%) from the acute phase to the 3MFU of which 27 were infected with omicron. CONCLUSION: With quality-controlled data from a multicenter cohort, we showed that PCC is an equally common challenge for patients infected with the SARS-CoV-2 variants delta and omicron at least for the German population. Developing the EQ-5D-5L index score trend groups showed that over two thirds of patients did not experience any restrictions in their HrQoL due to or after the SARS-CoV-2 infection at the 3MFU. CLINICAL TRAIL REGISTRATION: The cohort is registered at ClinicalTrials.gov since February 24, 2021 (Identifier: NCT04768998).

Antibody responses after sequential vaccination with PCV13 and PPSV23 in kidney transplant recipients.

PURPOSE: Vaccination against Streptococcus pneumoniae is recommended in transplant recipients to reduce the morbidity and mortality from invasive pneumococcal disease. Previous studies indicate that transplant recipients can produce specific antibodies after vaccination with the 13-valent pneumococcal conjugate vaccine Prevenar 13 (PCV13) or the pneumococcal polysaccharide vaccine Pneumovax 23 (PPSV23). National guidelines recommend sequential vaccination with PCV13 followed by PPSV23 in kidney transplant patients. However, there are currently no data on the serological response in kidney transplant recipients, who received a sequential vaccination with PCV13 and PPSV23. METHODS: In the current study, we sequentially vaccinated 46 kidney transplant recipients with PCV13 and PPSV23 and determined global and serotype-specific anti-pneumococcal antibody responses in the year following vaccination. RESULTS: Serotype-specific and global anti-pneumococcal antibody concentrations were significantly higher compared to baseline. We observed that serotype-specific antibody responses varied by serotype (between 2.2- and 2.9-fold increase after 12 months). The strongest responses after 12 months were detected against the serotypes 9N (2.9-fold increase) and 14 (2.8-fold increase). Global antibody responses also varied with respect to immunoglobulin class. IgG2 revealed the highest increase (2.7-fold), IgM the lowest (1.7-fold). Sequential vaccination with both vaccines achieved higher antibody levels in comparison with a historical cohort studied at our institute, that was vaccinated with PCV13 alone. During the 12-months follow-up period, none of the patients developed pneumococcal-associated pneumonia or vaccination-related allograft rejection. CONCLUSION: In conclusion, we strongly recommend sequential vaccination over single immunization in kidney transplant recipients.

Cellular Immunity in COVID-19 Convalescents with PCR-Confirmed Infection but with Undetectable SARS-CoV-2-Specific IgG.

We investigated immune responses against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among a group of convalescent, potential blood donors in Germany who had PCR-confirmed SARS-CoV-2 infection. Sixty days after onset of symptoms, 13/78 (17%) study participants had borderline or negative results to an ELISA detecting IgG against the S1 protein of SARS-CoV-2. We analyzed participants with PCR-confirmed infection who had strong antibody responses (ratio >3) as positive controls and participants without symptoms of SARS-CoV-2 infection and without household contact with infected patients as negative controls. Using interferon-γ ELISpot, we observed that 78% of PCR-positive volunteers with undetectable antibodies showed T cell immunity against SARS-CoV-2. We observed a similar frequency (80%) of T-cell immunity in convalescent donors with strong antibody responses but did not detect immunity in negative controls. We concluded that, in convalescent patients with undetectable SARS-CoV-2 IgG, immunity may be mediated through T cells.

Safety and Efficacy of 48 Weeks REP 2139 or REP 2165, Tenofovir Disoproxil, and Pegylated Interferon Alfa-2a in Patients With Chronic HBV Infection Naïve to Nucleos(t)ide Therapy.

BACKGROUND & AIMS: Nucleic acid polymers (NAPs) inhibit assembly and secretion of hepatitis B virus (HBV) subviral particles. We performed an open-label, phase 2 study of the safety and efficacy of the NAPs REP 2139 or REP 2165 combined with tenofovir disoproxil fumarate (TDF) and pegylated interferon alfa-2a (pegIFN) in patients with chronic HBV infection who were negative for hepatitis B e antigen. METHODS: Following 24 weeks TDF therapy, 40 patients were randomly assigned to groups that received 48 weeks of experimental therapy (TDF + pegIFN + REP 2139-Mg or REP 2165-Mg) or 24 weeks of control therapy (TDF + pegIFN) followed by 48 weeks of experimental therapy. Patients were then followed for a treatment-free period of 48 weeks. Primary outcomes were the safety and tolerability of REP 2139-Mg or REP 2165-Mg in combination with TDF + pegIFN compared with TDF + pegIFN alone through the first 48 weeks of therapy and subsequently throughout 48 weeks of NAP-based combination therapy (treatment weeks 24-72 in the experimental group and weeks 48-96 in the control group). Secondary outcomes were reductions in hepatitis B surface antigen (HBsAg) in control and experimental groups over the first 48 weeks of the study and throughout 48 weeks of combination therapy and virologic control (HBsAg positive, HBV DNA below 2000 IU/mL, normal level of alanine aminotransferase) or functional cure (HBsAg below 0.05 IU/mL, HBV DNA target not detected, normal level of alanine aminotransferase) after removal of all therapy. RESULTS: Levels of HBsAg, anti-HBs, and HBV DNA did not differ significantly between the groups given REP 2139 vs REP 2165. PegIFN-induced thrombocytopenia (P = .299 vs controls) and neutropenia (P = .112 vs controls) were unaffected by NAPs (REP 2139 vs REP 2165). Increases in levels of transaminases were significantly more frequent (P < .001 vs controls) and greater (P = .002 vs controls) in the NAP groups (but did not produce symptoms), correlated with initial decrease in HBsAg, and normalized during therapy and follow-up. During the first 24 weeks of TDF and pegIFN administration, significantly higher proportions of patients in NAP groups had decreases in HBsAg to below 1 IU/mL (P < .001 vs control) and HBsAg seroconversion (P = .046 vs control). At the time patients completed the TDF + pegIFN + NAP regimen, HBsAg levels were 0.05 IU/mL or lower in 24/40 participants (all with seroconversion up to 233,055 mIU/mL). During 48 weeks of treatment-free follow-up, virologic control persisted in 13 of 40 participants (2 lost to follow-up after 24 weeks), whereas functional cure persisted in 14 of 40 participants (all completing 48 weeks of follow-up) with persistent HBsAg seroconversion. One participant had a viral rebound during follow-up with hepatic decompensation and was placed on TDF therapy. CONCLUSIONS: In a phase 2 randomized trial, we found that addition of NAPs to TDF + pegIFN did not alter tolerability and significantly increased rates of HBsAg loss and HBsAg seroconversion during therapy and functional cure after therapy. Clinicaltrials.gov no: NCT02565719.

Cell Fusion Induced by a Fusion-Active Form of Human Cytomegalovirus Glycoprotein B (gB) Is Inhibited by Antibodies Directed at Antigenic Domain 5 in the Ectodomain of gB.

Human cytomegalovirus (HCMV) is a ubiquitous pathogen that can cause severe clinical disease in allograft recipients and infants infected in utero Virus-neutralizing antibodies defined in vitro have been proposed to confer protection against HCMV infection, and the virion envelope glycoprotein B (gB) serves as a major target of neutralizing antibodies. The viral fusion protein gB is nonfusogenic on its own and requires glycoproteins H (gH) and L (gL) for membrane fusion, which is in contrast to requirements of related class III fusion proteins, including vesicular stomatitis virus glycoprotein G (VSV-G) or baculovirus gp64. To explore requirements for gB's fusion activity, we generated a set of chimeras composed of gB and VSV-G or gp64, respectively. These gB chimeras were intrinsically fusion active and led to the formation of multinucleated cell syncytia when expressed in the absence of other viral proteins. Utilizing a panel of virus-neutralizing gB-specific monoclonal antibodies (MAbs), we could demonstrate that syncytium formation of the fusogenic gB/VSV-G chimera can be significantly inhibited by only a subset of neutralizing MAbs which target antigenic domain 5 (AD-5) of gB. This observation argues for differential modes of action of neutralizing anti-gB MAbs and suggests that blocking the membrane fusion function of gB could be one mechanism of antibody-mediated virus neutralization. In addition, our data have important implications for the further understanding of the conformation of gB that promotes membrane fusion as well as the identification of structures in AD-5 that could be targeted by antibodies to block this early step in HCMV infection.IMPORTANCE HCMV is a major global health concern, and antiviral chemotherapy remains problematic due to toxicity of available compounds and the emergence of drug-resistant viruses. Thus, an HCMV vaccine represents a priority for both governmental and pharmaceutical research programs. A major obstacle for the development of a vaccine is a lack of knowledge of the nature and specificities of protective immune responses that should be induced by such a vaccine. Glycoprotein B of HCMV is an important target for neutralizing antibodies and, hence, is often included as a component of intervention strategies. By generation of fusion-active gB chimeras, we were able to identify target structures of neutralizing antibodies that potently block gB-induced membrane fusion. This experimental system provides an approach to screen for antibodies that interfere with gB's fusogenic activity. In summary, our data will likely contribute to both rational vaccine design and the development of antibody-based therapies against HCMV.

Benefit of transaminase elevations in establishing functional cure of HBV infection during nap-based combination therapy.

Treatment of HBV infection with nucleic acid polymers and pegIFN is accompanied by transaminase elevations in 95% of participants. HBV viral rebound, partial cure (HBV DNA < 2000 IU/mL, normal ALT) or functional cure (HBV DNA target not detected, HBsAg 3X ULN while HBsAg was <1 IU/mL occurred in 3/11 (27%), 11/15 (74%) and 14/14 (100%) of participants experiencing viral rebound, partial or functional cure. ALT elevation >3X ULN during HBsAg <1 IU/mL and <10 IU/mL were the best predictors of partial and functional cure. In conclusion, elevations in ALT, AST or GGT while HBsAg <10 IU/ml during therapy with REP 2139 + pegIFN are associated with partial and functional cure. More potent HBsAg reduction during flare nadir is associated with the establishment of functional cure, suggesting a critical role for HBsAg-specific immunity to achieve this outcome. These on-therapy milestones may have similar positive prognostic value with other combination therapies.

SARS-CoV-2-specific humoral and cellular immunity in two renal transplants and two hemodialysis patients treated with convalescent plasma.

When patients with chronic kidney disease are infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) they can face two specific problems: virus-specific immune responses may be impaired and remdesivir, an antiviral drug described to shorten recovery, is contraindicated. Antiviral treatment with convalescent plasma (CP) could be an alternative treatment option. In this case report, we present two kidney transplant recipients and two hemodialysis patients who were infected with SARS-CoV-2 and received CP. Antibodies against the receptor-binding domain in the S1 subunit of the SARS-CoV-2 spike protein were determined sequentially by immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA) and neutralization assay and specific cellular responses by interferon-gamma ELISpot. Before treatment, in both kidney transplant recipients and one hemodialysis patient antibodies were undetectable by ELISA (ratio < 1.1), corresponding to low neutralizing antibody titers (≤1:40). ELISpot responses in the four patients were either weak or absent. After CP treatment, we observed an increase of SARS-CoV-2-specific antibodies (IgG ratio and neutralization titer) and of specific cellular responses. After intermittent clinical improvement, one kidney transplant recipient again developed typical symptoms on Day 12 after treatment and received a second cycle of CP treatment. Altogether, three patients clinically improved and could be discharged from the hospital. However, one 83-year-old multimorbid patient deceased. Our data suggest that the success of CP therapy may only be temporary in patients with chronic kidney disease; which requires close monitoring of viral load and antiviral immunity and possibly an adaptation of the treatment regimen.

Convalescent plasma treatment of critically ill intensive care COVID-19 patients.

BACKGROUND: Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may be life-threatening, and specific antiviral drugs are currently not available. However, first studies indicated that convalescent plasma treatment might improve the clinical outcome of coronavirus disease 2019 (COVID-19) patients. STUDY DESIGN AND METHODS: In the current study, we investigated the efficacy of convalescent plasma treatment in eight COVID-19 patients. All the patients were critically ill, and seven of them were SARS-CoV-2 RNA-positive when starting treatment. SARS-CoV-2-specific antibodies were determined by an enzyme-linked immunosorbent assay detecting immunoglobulin G (IgG) antibodies against the S1 protein (Euroimmun), and the neutralizing titers were determined with a cell-culture-based neutralization assay. Plasma treatment started between 4 and 23 days after the onset of symptoms. The patients were usually treated by three plasma units, each containing 200-280 ml, which was applied at day 1, 3, and 5. RESULTS: Donor sera had on average lower IgG antibody ratios and neutralizing titers than the COVID-19 patients before the onset of treatment (median ratio of 5.8 and neutralizing titer of 1:320 vs. 7.5 and 1:640, respectively). Nevertheless, we observed an increase of antibody ratios in seven and of neutralizing titers in five patients after treatment; which did, however, not correlate with patient survival. Plasma treatment was effective in three patients, but five deceased despite treatment. Patients who deceased had a later treatment onset than survivors and finally died from multiple organ failure. CONCLUSION: Our data indicate that the efficacy of convalescent plasma treatment of critically ill COVID-19 patients who already had developed strong antiviral immune responses and organ complications is limited.

Recent Antiviral Treatment and Vaccination Strategies Against SARS-CoV-2. / Aktuelle Möglichkeiten der antiviralen Therapie und Impfung bei SARS-CoV-2.

Since the end of 2019, the novel severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) has been spreading worldwide and has caused severe health and economic issues on a global scale. By the end of February 2021, more than 100 million SARS-CoV-2 cases had been reported worldwide. SARS-CoV-2 causes the coronavirus disease 2019 (COVID-19) that can be divided into three phases: An early phase with fever and cough (phase I), a pulmonary vascular disease (phase II) and a hyperinflammatory syndrome (phase III). Since viral replication plays a particularly important role in the early stage of the disease and the patient's immune system in the later course of infection, different therapeutic options arise depending on the stage of the disease. The antiviral nucleoside analogue remdesivir is the only antiviral compound with conditional approval in the European Union. Treatment with remdesivir should be initiated early (within the first seven days of symptom onset) in patients receiving supplemental oxygen without invasive ventilation. In turn, the anti-inflammatory corticosteroid dexamethasone should be administered later in the course of disease in patients receiving oxygen therapy. Since autopsies indicate an increased frequency of thromboembolic events due to COVID-19, additional treatment with anticoagulants is recommended. Since the development of novel antivirals may take years, the application of convalescent plasma from patients who recovered from a SARS-CoV-2 infection for the treatment of COVID-19 is reasonable. However, large-scale studies indicated low efficacy of convalescent plasma. Furthermore, vaccination of the population is essential to control the pandemic. Currently, the mRNA vaccine Tozinameran from BioNTech and Pfizer, the mRNA-1273 vaccine from Moderna as well as the vector vaccine AZD1222 from AstraZeneca are licensed in the European Union. All three vaccines have demonstrated high efficacy in large clinical trials. In addition to these licensed vaccines, many others are being tested in clinical trials. In the present article, an overview of therapeutic options for COVID-19 as well as vaccines for protection against SARS-CoV-2 is provided.

Virucidal Efficacy of Different Oral Rinses Against Severe Acute Respiratory Syndrome Coronavirus 2.

The ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic creates a significant threat to global health. Recent studies suggested the significance of throat and salivary glands as major sites of virus replication and transmission during early coronavirus disease 2019, thus advocating application of oral antiseptics. However, the antiviral efficacy of oral rinsing solutions against SARS-CoV-2 has not been examined. Here, we evaluated the virucidal activity of different available oral rinses against SARS-CoV-2 under conditions mimicking nasopharyngeal secretions. Several formulations with significant SARS-CoV-2 inactivating properties in vitro support the idea that oral rinsing might reduce the viral load of saliva and could thus lower the transmission of SARS-CoV-2.

Mutations in Hepatitis D Virus Allow It to Escape Detection by CD8+ T Cells and Evolve at the Population Level.

BACKGROUND & AIMS: Hepatitis D virus (HDV) superinfection in patients with hepatitis B virus (HBV) is associated with rapid progression to liver cirrhosis and hepatocellular carcinoma. Treatment options are limited, and no vaccine is available. Although HDV-specific CD8+ T cells are thought to control the virus, little is known about which HDV epitopes are targeted by virus-specific CD8+ T cells or why these cells ultimately fail to control the infection. We aimed to define how HDV escapes the CD8+ T-cell-mediated response. METHODS: We collected plasma and DNA samples from 104 patients with chronic HDV and HBV infection at medical centers in Europe and the Middle East, sequenced HDV, typed human leukocyte antigen (HLA) class I alleles from patients, and searched for polymorphisms in HDV RNA associated with specific HLA class I alleles. We predicted epitopes in HDV that would be recognized by CD8+ T cells and corresponded with the identified virus polymorphisms in patients with resolved (n = 12) or chronic (n = 13) HDV infection. RESULTS: We identified 21 polymorphisms in HDV that were significantly associated with specific HLA class I alleles (P < .005). Five of these polymorphisms were found to correspond to epitopes in HDV that are recognized by CD8+ T cells; we confirmed that CD8+ T cells in culture targeted these HDV epitopes. HDV variant peptides were only partially cross-recognized by CD8+ T cells isolated from patients, indicating that the virus had escaped detection by these cells. These newly identified HDV epitopes were restricted by relatively infrequent HLA class I alleles, and they bound most frequently to HLA-B. In contrast, frequent HLA class I alleles were not associated with HDV sequence polymorphisms. CONCLUSIONS: We analyzed sequences of HDV RNA and HLA class I alleles that present epitope peptides to CD8+ T cells in patients with persistent HDV infection. We identified polymorphisms in the HDV proteome that associate with HLA class I alleles. Some variant peptides in epitopes from HDV were only partially recognized by CD8+ T cells isolated from patients; these could be mutations that allow HDV to escape the immune response, resulting in persistent infection. HDV escape from the immune response was associated with uncommon HLA class I alleles, indicating that HDV evolves, at the population level, to evade recognition by common HLA class I alleles.

Induction of herpes simplex virus type 1 cell-to-cell spread inhibiting antibodies by a calcium phosphate nanoparticle-based vaccine.

Herpes simplex viruses 1 and 2 are among the most ubiquitous human infections and persist lifelong in their host. Upon primary infection or reactivation from ganglia, the viruses spread by direct cell-cell contacts (cell-to-cell spread) and thus escape from the host immune response. We have developed a monoclonal antibody (mAb 2c), which inhibits the HSV cell-to-cell spread, thereby protecting from lethal genital infection and blindness in animal models. In the present study we have designed a nanoparticle-based vaccine to induce protective antibody responses exceeding the cell-to-cell spread inhibiting properties of mAb 2c. We used biodegradable calcium phosphate (CaP) nanoparticles coated with a synthetic peptide that represents the conformational epitope on HSV-1 gB recognized by mAb 2c. The CaP nanoparticles additionally contained a TLR-ligand CpGm and were formulated with adjuvants to facilitate the humoral immune response. This vaccine effectively protected mice from lethal HSV-1 infection by inducing cell-to-cell spread inhibiting antibodies.

Identification of Elite Neutralizers With Broad and Potent Neutralizing Activity Against Human Cytomegalovirus (HCMV) in a Population of HCMV-Seropositive Blood Donors.

To improve the potency of anti-human cytomegalovirus (HCMV) immunoglobulin preparations, we intended to find elite neutralizers among 9000 HCMV-seropositive blood donors. We identified the top 2.6% neutralizers by use of high-throughput screening and further analyzed the 80 neutralizers with the most effective plasma for strain-independent activity. Of those, 58 had broad neutralizing activity against various HCMV strains and hence were regarded as elite neutralizers. All elite neutralizers were then analyzed to determine their effect on individual virus particles during entry. Most had plasma specimens that preferentially inhibited viral penetration, whereas 2 had exceptional plasma specimens that prevented adsorption of virus to cells. Furthermore, the neutralizing capacity of plasma samples from 3 randomly chosen elite neutralizers was up to 10-fold higher than that for commercial immunoglobulins. In a retrospective analysis of 6 selected donors, anti-HCMV neutralization titers in repeated donations were constantly high over 5 years. In conclusion, plasma samples from elite-neutralizing donors can be considered to improve antibody-based treatment of HCMV infections.

Overcoming drug-resistant herpes simplex virus (HSV) infection by a humanized antibody.

Despite the availability of antiviral chemotherapy, herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) infections remain a severe global health problem. Of particular concern is the growing incidence of drug resistance in immunocompromised patients, which stresses the urgency to develop new effective treatment alternatives. We have developed a humanized monoclonal antibody (mAb hu2c) that completely abrogates viral cell-to-cell spread, a key mechanism by which HSV-1/2 escapes humoral immune surveillance. Moreover, mAb hu2c neutralized HSV fully independent of complement and/or immune effector cell recruitment in a highly efficient manner. Prophylactic and therapeutic administration of mAb hu2c completely prevented infection-related mortality of severely immunodeficient mice being challenged with a lethal dose of HSV-1. The high neutralization capacity of mAb hu2c was fully maintained toward clinical HSV isolates being multiresistant to standard antiviral drugs, and infection was fully resolved in 7/8 nonobese diabetic/SCID mice being infected with a multidrug resistant HSV-1 patient isolate. Immunohistochemical studies revealed no significant cross-reactivity of the antibody toward human tissues. These features warrant further clinical development of mAb hu2c as an immunotherapeutic compound for the management of severe and particularly drug-resistant HSV infections.

Frequency of SARS-CoV-2 Infections among Healthcare Workers in Germany: 3-Year Follow-Up Study.

The emergence of SARS-CoV-2 in 2019 led to a global pandemic with a significant impact on healthcare systems. Healthcare workers were particularly vulnerable due to frequent contact with COVID-19 patients. Despite vaccination, they remained at higher risk as the vaccines provided limited protection against infection with viral variants, like Delta or Omicron BA.1 and BA.5. Three years after the onset of the pandemic, we evaluated SARS-CoV-2 infection frequencies among healthcare workers with varying levels of patient contact: high-risk (frequent COVID-19 patient contact), intermediate-risk (non-COVID-19 patient contact), and low-risk (no patient contact). We assessed their cellular and humoral immune responses based on their vaccination status and number of prior infections. SARS-CoV-2-specific antibodies were measured by immunoglobulin ELISA, and neutralizing antibody titers were determined against the viral variants D614G, Delta, and Omicron BA.1 and BA.5. Cellular immune responses were analyzed using an interferon-γ ELISpot. Notably, three years into the pandemic, healthcare workers in daily contact with COVID-19 patients did not have higher infection rates compared to healthcare workers with non-COVID-19 patient contact or no patient contact. Immune responses were similar across all groups, highlighting the effectiveness of vaccination and current hygiene standards in preventing virus transmission from patients to staff.

Antibody responses after sequential vaccination with PCV13 and PPSV23 in patients with moderate to severe plaque psoriasis under immunosuppressive therapy.

A crucial step in lowering the risk of invasive pneumococcal illness in high-risk populations, such as individuals with plaque psoriasis, is pneumococcal vaccination. The serologic response to the sequential vaccination with Prevenar 13 (PCV13) and Pneumovax 23 (PPSV23) in psoriasis patients under immunosuppressive therapy is still poorly characterized despite national recommendations suggesting vaccination for immunocompromised patients. In this prospective study, we investigated the serological response in 57 patients under active systemic treatment for moderate to severe plaque psoriasis who underwent sequential vaccination with PCV13 followed by PPSV23. Our analysis focused on global and serotype-specific anti-pneumococcal antibody responses over a 7-month period post-vaccination. Our findings reveal a robust serological response in patients with plaque psoriasis under systemic therapy. When comparing our results with a cohort of kidney transplant recipients who completed a similar sequential vaccination protocol, psoriasis patients showed higher antibody concentrations. In psoriasis patients, the mean levels of all global antibody classes tested (IgG, IgG2, IgA, IgM) increased more than 4-fold (P < 0.0001) and serotype-specific antibodies more than 1.9-fold (P < 0.01). In addition to providing strong evidence of the safety and effectiveness of sequential pneumococcal vaccination in individuals with plaque psoriasis, our work sheds light on the complex interactions that exist between immunosuppressive treatment, vaccination schedule, and antibody responses in various risk groups. IMPORTANCE: To protect against severe courses of infection with Streptococcus pneumoniae, the national guidelines recommend sequential vaccination for these patients. However, there are only studies on the efficacy of a single administration of these vaccines in this particular risk group. The immunological responses to the vaccine were correlated with clinical patient data. In summary, our study shows for the first time that sequential vaccination is immunogenic in patients with moderate to severe plaque psoriasis.

Immunogenicity of the Monovalent Omicron XBB.1.5-Adapted BNT162b2 COVID-19 Vaccine in People Living with HIV (PLWH).

While SARS-CoV-2 has transitioned to an endemic phase, infections caused by newly emerged variants continue to result in severe, and sometimes fatal, outcomes or lead to long-term COVID-19 symptoms. Vulnerable populations, such as PLWH, face an elevated risk of severe illness. Emerging variants of SARS-CoV-2, including numerous Omicron subvariants, are increasingly associated with breakthrough infections. Adapting mRNA vaccines to these new variants may offer improved protection against Omicron for vulnerable individuals. In this study, we examined humoral and cellular immune responses before and after administering adapted booster vaccinations to PLWH, alongside a control group of healthy individuals. Four weeks following booster vaccination, both groups exhibited a significant increase in neutralizing antibodies and cellular immune responses. Notably, there was no significant difference in humoral immune response between PLWH and the healthy controls. Immune responses declined rapidly in both groups three months post vaccination. However, PLWH still showed significantly increased neutralizing antibody titers even after three months. These findings demonstrate the efficacy of the adapted vaccination regimen. The results suggest that regular booster immunizations may be necessary to sustain protective immunity.