Pre-existing humoral immunity and CD4+ T cell response correlate with cross-reactivity against SARS-CoV-2 Omicron subvariants after heterologous prime-boost vaccination.

BACKGROUND: Information regarding the heterologous prime-boost COVID vaccination has been fully elucidated. The study aimed to evaluate both humoral, cellular immunity and cross-reactivity against variants after heterologous vaccination. METHODS: We recruited healthcare workers previously primed with Oxford/AstraZeneca ChAdOx1-S vaccines and boosted with Moderna mRNA-1273 vaccine boost to evaluate the immunological response. Assay used: anti-spike RBD antibody, surrogate virus neutralizing antibody and interferon-γ release assay. RESULTS: All participants exhibited higher humoral and cellular immune response after the booster regardless of prior antibody level, but those with higher antibody level demonstrated stronger booster response, especially against omicron BA.1 and BA.2 variants. The pre-booster IFN-γ release by CD4+ T cells correlates with post-booster neutralizing antibody against BA.1 and BA.2 variant after adjustment with age and gender. CONCLUSIONS: A heterologous mRNA boost is highly immunogenic. The pre-existing neutralizing antibody level and CD4+ T cells response correlates with post-booster neutralization reactivity against the Omicron variant.

Negative regulation of type I interferon signaling by integrin-linked kinase permits dengue virus replication.

Dengue virus (DENV) infection can induce life-threatening dengue hemorrhagic fever/dengue shock syndrome in infected patients. DENV is a threat to global health due to its growing numbers and incidence of infection in the last 50 years. During infection, DENV expresses ten structural and nonstructural proteins modulating cell responses to benefit viral replication. However, the lack of knowledge regarding the cellular proteins and their functions in enhancing DENV pathogenesis impedes the development of antiviral drugs and therapies against fatal DENV infection. Here, we identified that integrin-linked kinase (ILK) is a novel enhancing factor for DENV infection by suppressing type I interferon (IFN) responses. Mechanistically, ILK binds DENV NS1 and NS3, activates Akt and Erk, and induces NF-κB-driven suppressor of cytokine signaling 3 (SOCS3) expression. Elevated SOCS3 in DENV-infected cells inhibits phosphorylation of STAT1/2 and expression of interferon-stimulated genes (ISGs). Inhibiting ILK, Akt, or Erk activation abrogates SOCS3 expression. In DENV-infected mice, the treatment of an ILK inhibitor significantly reduces viral loads in the brains, disease severity, and mortality rate. Collectively, our results show that ILK is a potential therapeutic target against DENV infection.

COVID-19 associated mold infections: Review of COVID-19 associated pulmonary aspergillosis and mucormycosis.

COVID-19-associated mold infection (CAMI) is defined as development of mold infections in COVID-19 patients. Co-pathogenesis of viral and fungal infections include the disruption of tissue barrier following SARS CoV-2 infection with the damage in the alveolar space, respiratory epithelium and endothelium injury and overwhelming inflammation and immune dysregulation during severe COVID-19. Other predisposing risk factors permissive to fungal infections during COVID-19 include the administration of immune modulators such as corticosteroids and IL-6 antagonist. COVID-19-associated pulmonary aspergillosis (CAPA) and COVID-19-associated mucormycosis (CAM) is increasingly reported during the COVID-19 pandemic. CAPA usually developed within the first month of COVID infection, and CAM frequently arose 10-15 days post diagnosis of COVID-19. Diagnosis is challenging and often indistinguishable during the cytokine storm in COVID-19, and several diagnostic criteria have been proposed. Development of CAPA and CAM is associated with a high mortality despiteappropriate anti-mold therapy. Both isavuconazole and amphotericin B can be used for treatment of CAPA and CAM; voriconazole is the primary agent for CAPA and posaconazole is an alternative for CAM. Aggressive surgery is recommended for CAM to improve patient survival. A high index of suspicion and timely and appropriate treatment is crucial to improve patient outcome.

A novel chimeric dengue vaccine candidate composed of consensus envelope protein domain III fused to C-terminal-modified NS1 protein.

There is an urgent need for a safe and effective vaccine against dengue virus (DENV) which infects about 390 million humans per year. In the present study we combined modifications of two DENV proteins, the nonstructural protein 1 (NS1) and the envelope (E) protein, to produce a DENV vaccine candidate with enhanced features. One of these modified proteins was a C-terminal-deleted fragment of NS1 called ΔC NS1 which we have shown previously to be protective without the potentially harmful effects of cross-reactive epitopes common to surface antigens on platelets and endothelial cells. The other modified protein was an envelope protein domain III (cEDIII) containing a consensus amino acid sequence among the four serotypes of DENV, which induces neutralizing antibody against all four DENV serotypes. The cEDIII and ΔC NS1 were expressed as a fusion protein cEDIII-ΔC NS1 and its protective effects against DENV were evaluated in a mouse model. C3H/HeN mice were immunized three times with cEDIII-ΔC NS1 fusion protein mixed with alum as adjuvant. Sera collected from cEDIII-ΔC NS1-immunized mice neutralized four serotypes of DENV and also caused complement-mediated cytolysis of HMEC-1 cells infected with each of the four different DENV serotypes. Mice immunized with cEDIII-ΔC NS1 and challenged with DENV showed reduced serum virus titer, soluble NS1 and bleeding time, compared with mice infected with DENV alone. The results reveal that antibodies induced by cEDIII-ΔC NS1 not only show anti-viral efficacy by in vitro assays but also provide protective effects against DENV infection in a mouse model. The cEDIII-ΔC NS1 thus represents a novel, effective DENV vaccine candidate.

DNA-induced 2'3'-cGAMP enhances haplotype-specific human STING cleavage by dengue protease.

The cytosolic DNA sensor cGMP-AMP synthase (cGAS) synthesizes the noncanonical cyclic dinucleotide 2'3'-cGAMP to activate the adaptor protein stimulator of IFN genes (STING), thus awakening host immunity in response to DNA pathogen infection. However, dengue virus (DENV), an RNA virus without a DNA stage in its life cycle, also manipulates cGAS-STING-mediated innate immunity by proteolytic degradation of STING. Here, we found that the sensitivity of STING to DENV protease varied with different human STING haplotypes. Exogenous DNA further enhanced DENV protease's ability to interact and cleave protease-sensitive STING. DNA-enhanced STING cleavage was reduced in cGAS-knockdown cells and triggered by the cGAS product 2'3'-cGAMP. The source of DNA may not be endogenous mitochondrial DNA but rather exogenous reactivated viral DNA. Cells producing 2'3'-cGAMP by overexpressing cGAS or with DNA virus reactivation enhanced STING cleavage in neighboring cells harboring DENV protease. DENV infection reduced host innate immunity in cells with the protease-sensitive STING haplotype, whose homozygote genotype frequency was found significantly reduced in Taiwanese people with dengue fever. Therefore, the human STING genetic background and DNA pathogen coinfection may be the missing links contributing to DENV pathogenesis.

Comparative study of clinical and epidemiological characteristics of major pediatric adenovirus epidemics in southern Taiwan.

BACKGROUND: Human adenoviruses (HAdV) are important pathogens of pediatric respiratory tract infections in Taiwan. There were two major HAdV epidemics in southern Taiwan in 2011 and 2014, respectively. METHODS: The demographic, clinical characteristics, and risk factors for hospitalization of pediatric patients with HAdV infection in the two outbreaks were retrospectively compared. The epidemic was defined as > 7% HAdV detection rate for six consecutive weeks. HAdV infection was defined as positive HAdV isolates from respiratory tract specimens. HAdV genotype was determined by PCR-based hexon gene sequencing. RESULTS: A total of 1145 pediatric patients were identified (635 cases in 2011; 510 cases in 2014). HAdV genotype 3 and 7 contributed to both epidemics, although the proportion of HAdV3 decreased significantly (64.7% in 2011 to 25.5% in 2014, p < 0.001) and was replaced by other genotypes (type 1, 4, and 6) in the 2014 epidemic. Among the hospitalized patients, there were more patients hospitalized with bronchopneumonia/or pneumonia in the 2011 epidemic (10.6% vs 5.1%, p < 0.001), while more patients hospitalized with acute pharyngitis/pharyngoconjunctival fever (63.9% vs. 38.6%, p < 0.001) in the 2014 epidemic. In both epidemics, hospitalized patients had higher WBC and C-reactive protein (CRP) levels than non-hospitalized patients. Using multivariate regression analysis, underlying disease and elevated CRP levels were independent risk factors for hospitalization in both epidemics. CONCLUSION: There were significant differences in clinical, viral characteristics and risk factors of hospitalization between the 2011 and 2014 epidemics. Understanding changes in the epidemiological and clinical characteristics of HAdV epidemics is important from a public health perspective.

Clinical features of community acquired adenovirus pneumonia during the 2011 community outbreak in Southern Taiwan: role of host immune response.

BACKGROUND: Human adenovirus 7 (HAdV-7) was responsible for a significant number of fatalities during the 2011 community outbreak in Taiwan. The mechanisms underlying the pathogenesis of severe adenovirus infections in non-immunocompromised individuals remain unclear. Adenovirus pneumonia was associated with pleural effusion in a number of patients from the 2011 outbreak suggesting that similar to bacterial pneumonia, patients diagnosed with adenovirus pneumonia who have pleural effusion are more severely and systemically infected, and may have a more protracted disease course. We hypothesized that the host immunological response determines the severity of adenoviral infection. METHODS: This retrospective case series study included patients diagnosed with severe lower respiratory tract infections at the National Cheng Kung University Hospital in southern Taiwan between December 2010 and October 2011. The main inclusion criteria were 1) presence of multifocal patchy infiltrates, lobar consolidation or reticular interstitial opacities in chest X-rays, and 2) presence of adenovirus isolated from respiratory specimens. All patients had adenovirus isolated from respiratory specimens, and were negative for other viruses. Pleural effusion was confirmed in all patients using chest echography. Clinical features and laboratory data were compared in patients with (n = 12) and without (n = 15) parapneumonic effusion. RESULTS: Presence of parapneumonic effusion was significantly associated with a longer febrile duration, more complicated clinical management, and a greater risk of extrapulmonary involvement, notably hepatitis. Patients without pleural effusion had significantly higher numbers of WBCs, platelets, and absolute segment cell counts (ASCs) compared to patients with pleural effusion (all p < 0.05). Patients without pleural effusion had significantly higher counts of CD4+, CD8+, and CD20+ T cells (all p < 0.05) compared to patients with pleural effusion. CONCLUSION: Our data indicated that presence of parapneumonic effusion in adenoviral pneumonia was associated with longer febrile duration, more complicated clinical management, a greater risk of hepatitis, and suppression of host cellular immunity. Further prospective, large-scale studies are needed to validate our results.

Resveratrol treatment reveals a novel role for HMGB1 in regulation of the type 1 interferon response in dengue virus infection.

Dengue is one of the most significant mosquito-borne virus diseases worldwide, particularly in tropical and subtropical regions. This study sought to examine the antiviral activity of resveratrol (RESV), a phytoalexin secreted naturally by plants, against dengue virus (DENV) infection. Our data showed that RESV inhibits the translocation of high mobility group box 1 (HMGB1), a DNA binding protein that normally resides in the nucleus, into the cytoplasm and extracellular milieu. HMGB1 migrates out of the nucleus during DENV infection. This migration is inhibited by RESV treatment and is mediated by induction of Sirt1 which leads to the retention of HMGB1 in the nucleus and consequently helps in the increased production of interferon-stimulated genes (ISGs). Nuclear HMGB1 was found to bind to the promoter region of the ISG and positively regulated the expression of ISG. The enhanced transcription of ISGs by nuclear HMGB1 thus contributes to the antiviral activity of RESV against DENV. To the best of our knowledge, this is the first report to demonstrate that RESV antagonizes DENV replication and that nuclear HMGB1 plays a role in regulating ISG production.

Bloodstream infections in pediatric patients with acute leukemia: Emphasis on gram-negative bacteria infections.

BACKGROUND/PURPOSE: Acute leukemia is the most common pediatric hematological malignancy. Bloodstream infections (BSIs) are severe complications in these patients during chemotherapy. This study aims to explore clinical features, laboratory, and microbiological characteristics of BSIs in acute leukemic children. METHODS: Patients aged < 18 years, diagnosed with acute myeloid leukemia or acute lymphocytic leukemia with BSIs from January 2004 to December 2013 were enrolled. BSIs was defined as positive isolate(s) of blood culture and associated with clinical findings. Clinical presentations, demographic features, and microbiological findings were retrospectively reviewed. RESULTS: In total, 126 isolates of 115 episodes of BSIs were identified from 69 patients (acute lymphocytic leukemia 56; acute myeloid leukemia 13). Gram-negative bacteria (GNB), gram-positive cocci, and fungi constituted 56.3%, 42.3%, and 2.4% of the pathogens, respectively. Eighty-three and a half percent of BSIs occurred along with neutropenia, and 73% had severe neutropenia. GNB was the leading pathogen of BSIs. The major GNBs were Escherichia coli, Klebsiella pneumonia, and Pseudomonas aeruginosa. White blood cell counts, absolute neutrophil counts, and platelet counts were significantly lower in patients of BSIs caused by GNB than gram-positive cocci. Plasma level of C-reactive protein was significant high in patients of GNB BSIs (179.8 mg/L vs. 127.2 mg/L; p = 0.005). Eighty-two percent of patients of E. coli, K. pneumonia, and P. aeruginosa BSIs had sepsis related organ failure or organ dysfunction. P. aeruginosa BSIs had the highest case-mortality (40%). CONCLUSION: Neutropenia was the major risk factor of BSIs in pediatric leukemic patients. BSIs of GNB were associated with severe neutropenia, systemic inflammatory responses, and high mortality.

Monoclonal antibodies for diagnosis of enterovirus 71.

Enterovirus 71 (EV71), one of the major causative agents of hand, foot, and mouth disease (HFMD), is now recognized as an emerging neurotropic virus in Asia and may cause severe neurologic complications and mortalities. Laboratory diagnosis of EV71 infection must be efficient and accurate, which could be accomplished by various immunoassays. In this study we use a live EV71 isolate, Tainan/4643/98, with genotype C2 as an immunogen to sensitize BALB/c (H-2(d)) mice and then generate the EV71-specific murine monoclonal antibodies. Five hybridoma clones were established and their monoclonal antibodies were characterized. All five clones are applicable in immunofluorescence staining but with different sensitivities-that is, MAbs 22, 24, and 27 were sensitive in IFA detection, and MAbs 22 and 24 were also confirmed in flow cytometry. None of these cross-reacted with coxsackievirus A16 (CVA16) or Echovirus type 6 (ECHO6), but each varied in binding to different EV71 subgenogroups (B1, B4, B5, C2, and C4). Western blot analysis revealed that all of these MAbs reacted with EV71 VP1 capsid proteins, and in addition MAbs 22 and 24 exhibited potent neutralizing activities against EV71 and protected cells from infection. Further, mapping the epitopes for each MAb revealed that only MAb 27 showed positive for the linear epitope DVIESSIGDSVSRAL, which was located at the N-terminus (a.a. 6-20) of EV71 VP1 and highly conserved among all EV71 subgenotypes. Thus, these MAbs may provide valuable tools for the laboratory diagnosis of EV71 infection and for vaccine development.

Clinical and laboratory characteristics of human immunodeficiency virus-infected adolescents: experience from a single medical center.

BACKGROUND: Recently, the proportion of adolescents diagnosed with human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) has increased. The aim of this study is to evaluate the clinical and laboratory characteristics of HIV-infected adolescents in southern Taiwan. METHODS: From June 1997 to December 2010, a total of 40 HIV-infected adolescents who sought medical care in a university hospital in southern Taiwan were enrolled in the study. They were classified into three HIV at-risk groups, men who have sex with men (MSM), heterosexuals, and intravenous drug users (IDUs). Clinical and laboratory data were obtained from medical records. RESULTS: The median age of the 40 HIV-infected adolescents was 19 years. The HIV at-risk groups were MSM (22/40, 55%), heterosexuals (7/40, 17.5%), IDUs (5/40, 12.5%), and unknown (6/40, 15%). The initial median CD4 count and log plasma HIV viral load were 318 cells/mm(3) and 4.61, respectively. The seroprevalence of anti-HAV, anti-HBc, anti-HCV antibodies and HBsAg was 5.3%, 26.1%, 13% and 13%, respectively. Among 17 adolescents who had regular follow-ups more than twice, 7 (41.2%) had a concurrent sexually transmitted disease (STD). The most common STD was genital warts (41.2%) followed by syphilis (11.8%). Among 7 patients who received highly active antiretroviral agents (HAART) for more than 12 months, 5 (71.4%) had sustained virologic suppression. CONCLUSION: MSM are the largest risk group in HIV-infected adolescents in southern Taiwan and are characterized by a high prevalence of anogenital warts and low seroprevalence of anti-HAV.