Design and synthesis of HLA-A*02-restricted Hantaan virus multiple-antigenic peptide for CD8+ T cells.

BACKGROUND: Hantaan virus (HTNV) can cause hemorrhagic fever with renal syndrome (HFRS) in humans with severe morbidity and high mortality. Although inactivated HFRS vaccines are given annually for prevention in populations, China still has the highest number of HFRS cases and deaths worldwide. Consequently, vaccination for HFRS requires the development of novel, more effective vaccines. Epitope peptide vaccines have been developed rapidly in recent years and are considered a novel approach for the prevention of infection. Specifically, the multiple antigenic peptide (MAP) design with preferable immunogenicity can arouse a satisfactory immune response for vaccination. However, there are few reports on the design and evaluation of MAP for HTNV. METHODS: Three HLA-A*02-restricted 9-mer cytotoxic T lymphocyte (CTL) epitopes on HTNV glycoprotein and one HLA-A*02-restricted 9-mer CTL epitope on the HTNV nucleocapsid, which have been proven to be immunoprotective in our previous study, were selected for the design of HTNV MAP. A four-branched HTNV MAP was evaluated by the IFN-γ-secreting enzyme-linked immunospot assay and proliferation induction capacity of CD8+ T cells and compared with the single HTNV CTL epitope in 17 HLA-A*02+ patients with HFRS. The Mann-Whitney U test was used for comparison of parameters between different subject groups. RESULTS: The macromolecular HTNV MAP was designed with a polylysine core and four radially branched single CTL epitope chains. Importantly, HTNV MAP could stimulate CD8+ T cell secretion of IFN-γ in HLA-A*02+ patients with HFRS. The frequency of IFN-γ-secreting CD8+ T cells in the MAP stimulation group was significantly higher than that in the single HTNV CTL epitope stimulation groups (P < 0.005). Meanwhile, the activity of IFN-γ-secreting CD8+ T cells in the HTNV MAP group was also higher than that of the single CTL epitope groups (P < 0.05). Moreover, there was a much stronger ability of HTNV MAP to stimulate CD8+ T cell proliferation compared with that of a single HTNV CTL epitope. CONCLUSIONS: The designed HTNV MAP could induce CTL responses ex vivo and may be considered a candidate for the design and development of novel HTNV peptide vaccines.

Protective CD8+ T-cell response against Hantaan virus infection induced by immunization with designed linear multi-epitope peptides in HLA-A2.1/Kb transgenic mice.

BACKGROUND: An effective vaccine that prevents disease caused by hantaviruses is a global public health priority, but up to now, no vaccine has been approved for worldwide use. Therefore, novel vaccines with high prophylaxis efficacy are urgently needed. METHODS: Herein, we designed and synthesized Hantaan virus (HTNV) linear multi-epitope peptide consisting of HLA-A*02-restricted HTNV cytotoxic T cell (CTL) epitope and pan HLA-DR-binding epitope (PADRE), and evaluated the immunogenicity, as well as effectiveness, of multi-epitope peptides in HLA-A2.1/Kb transgenic mice with interferon (IFN)-γ enzyme-linked immunospot assay, cytotoxic mediator detection, proliferation assay and HTNV-challenge test. RESULTS: The results showed that a much higher frequency of specific IFN-γ-secreting CTLs, high levels of granzyme B production, and a strong proliferation capacity of specific CTLs were observed in splenocytes of mice immunized with multi-epitope peptide than in those of a single CTL epitope. Moreover, pre-immunization of multi-epitope peptide could reduce the levels of HTNV RNA loads in the liver, spleen and kidneys of mice, indicating that specific CTL responses induced by multi-epitope peptide could reduce HTNV RNA loads in vivo. CONCLUSIONS: This study may provide an important foundation for the development of novel peptide vaccines for HTNV prophylaxis.

A case-control study on the risk factors for hemorrhagic fever with renal syndrome.

BACKGROUND: Hemorrhagic fever with renal syndrome (HFRS) is an endemic communicable disease in China, accounting for 90% of total reported cases worldwide. In this study, the authors want to investigate the risk factors for HFRS in recent years to provide the prevention and control advices. METHODS: A community-based, 1:2 matched case-control study was carried out to investigate the risk factors for HFRS. Cases were defined as laboratory-confirmed cases that tested positive for hantavirus-specific IgM antibodies. Two neighbourhood controls of each case were selected by sex, age and occupation. Standardized questionnaires were used to collect information and identify the risk factors for HFRS. RESULTS: Eighty-six matched pairs were investigated in the study. The median age of the cases was 55.0 years, 72.09% were male, and 73.26% were farmers. In the multivariate logistic regression analysis, cleaning spare room at home (OR = 3.310, 95%CI 1.335-8.210) was found to be risk factor for infection; storing food and crops properly (OR = 0.279 95%CI 0.097-0.804) provided protection from infection. CONCLUSION: Storing food and crops properly seemed to be protective factor, which was important for HFRS prevention and control. More attention should be paid to promote comprehensive health education and behaviour change among high-risk populations in the HFRS endemic area.

Recent Increase of Human Granulocytic Anaplasmosis and Co-Infection with Scrub Typhus or Korean Hemorrhagic Fever with Renal Syndrome in Korea.

We report 17 patients with human granulocytic anaplasmosis between January 2015 and September 2018 at two tertiary university hospitals in Korea. Monthly incidence peaked in May and June. Among these patients, we identified three who were co-infected with scrub typhus, and one patient with hemorrhagic fever with renal syndrome.

The Long Noncoding RNA NEAT1 Exerts Antihantaviral Effects by Acting as Positive Feedback for RIG-I Signaling.

Hantavirus infection, which causes zoonotic diseases with a high mortality rate in humans, has long been a global public health concern. Over the past decades, accumulating evidence suggests that long noncoding RNAs (lncRNAs) play key regulatory roles in innate immunity. However, the involvement of host lncRNAs in hantaviral control remains uncharacterized. In this study, we identified the lncRNA NEAT1 as a vital antiviral modulator. NEAT1 was dramatically upregulated after Hantaan virus (HTNV) infection, whereas its downregulation in vitro or in vivo delayed host innate immune responses and aggravated HTNV replication. Ectopic expression of NEAT1 enhanced beta interferon (IFN-ß) production and suppressed HTNV infection. Further investigation suggested that NEAT1 served as positive feedback for RIG-I signaling. HTNV infection activated NEAT1 transcription through the RIG-I-IRF7 pathway, whereas NEAT1 removed the transcriptional inhibitory effects of the splicing factor proline- and glutamine-rich protein (SFPQ) by relocating SFPQ to paraspeckles, thus promoting the expression of RIG-I and DDX60. RIG-I and DDX60 had synergic effects on IFN production. Taken together, our findings demonstrate that NEAT1 modulates the innate immune response against HTNV infection, providing another layer of information about the role of lncRNAs in controlling viral infections.IMPORTANCE Hantaviruses have attracted worldwide attention as archetypal emerging pathogens. Recently, increasing evidence has highlighted long noncoding RNAs (lncRNAs) as key regulators of innate immunity; however, their roles in hantavirus infection remain unknown. In the present work, a new unexplored function of lncRNA NEAT1 in controlling HTNV replication was found. NEAT1 promoted interferon (IFN) responses by acting as positive feedback for RIG-I signaling. This lncRNA was induced by HTNV through the RIG-I-IRF7 pathway in a time- and dose-dependent manner and promoted HTNV-induced IFN production by facilitating RIG-I and DDX60 expression. Intriguingly, NEAT1 relocated SFPQ and formed paraspeckles after HTNV infection, which might reverse inhibitive effects of SFPQ on the transcription of RIG-I and DDX60. To the best of our knowledge, this is the first study to address the regulatory role of the lncRNA NEAT1 in host innate immunity after HTNV infection. In summary, our findings provide additional insights regarding the role of lncRNAs in controlling viral infections.

Involvement of CD8+ T cells in the development of renal hemorrhage in a mouse model of hemorrhagic fever with renal syndrome.

Hemorrhagic fever with renal syndrome (HFRS) is caused by hantavirus infection. Although host immunity is thought to be involved in the pathogenesis of HFRS, the mechanism remains to be elucidated. A mouse model of HFRS, which showed renal hemorrhage similar to that seen in patients, has been developed previously. In this study, we aimed to clarify whether CD4+ and CD8+ T cells are involved in the development of renal hemorrhage in the mouse model. At 2 days before virus inoculation, CD4+ or CD8+ T cells in 6-week-old BALB/c mice were depleted by administration of antibodies. The CD4+ T cell-depleted mice developed signs of disease such as transient weight loss, ruffled fur and renal hemorrhage as in non-depleted mice. In contrast, the CD8+ T cell-depleted mice showed no signs of disease. After determination of CTL epitopes on the viral glycoprotein in BALB/c mice, the quantity of virus-specific CTLs was analyzed using an MHC tetramer. The quantity of virus-specific CTLs markedly increased in spleens and kidneys of virus-infected mice. However, the quantity in high-pathogenic clone-infected mice was comparable to that in low-pathogenic clone-infected mice. We previously reported that the high-pathogenic clone propagated more efficiently than the low-pathogenic clone in kidneys of mice during the course of infection. Therefore, there is a possibility that the balance between quantities of the target and effector is important for disease outcome. In conclusion, this study showed that CD8+ T cells are involved in the development of renal hemorrhage in a mouse model of HFRS.

HTNV-induced upregulation of miR-146a in HUVECs promotes viral infection by modulating pro-inflammatory cytokine release.

Increasing research has shown a link between viruses and miRNAs, such as miRNA-146a, in regulating virus infection and replication. In the current study, the association between miR-146a and hantaan virus (HTNV) infection in human umbilical vein endothelial cells (HUVECs) was investigated, with a focus on examining the expression of pro-inflammatory cytokines. The results showed that HTNV infection promoted the production of miR-146a in HUVECs and activated nuclear factor-κB (NF-κB) signaling, along with the upregulation of pro-inflammatory cytokines, including interleukin 8 (IL-8), C-C Motif Chemokine Ligand 5 (CCL5, also RANTES), interferon-inducible protein-10 (IP-10) and interferon beta (IFN-ß). Moreover, miR-146a exhibited a negative regulatory effect on the NF-κB pathway. Accordingly, a miR-146a inhibitor increased the expression of IL-8, CCL5, IP-10 and IFN-ß, whereas a miR-146a mimic reduced the levels of these cytokines. Consequently, exogenous transduction of miR-146a significantly enhanced HTNV replication in HUVEC cells. We also discovered that viral proteins (NP/GP) contributed to miR-146a expression via enhancement the activity of miR-146a promoter. In conclusion, these results imply the negative regulation of miR-146a on the production of HTNV-induced pro-inflammatory cytokines contributes to virus replication, which suggest that miR-146a may be regarded as a novel therapeutic target for HTNV infection.

Hantaan virus infection induces both Th1 and ThGranzyme B+ cell immune responses that associated with viral control and clinical outcome in humans.

Hantaviruses infection causing severe emerging diseases with high mortality rates in humans has become public health concern globally. The potential roles of CD4(+)T cells in viral control have been extensively studied. However, the contribution of CD4(+)T cells to the host response against Hantaan virus (HTNV) infection remains unclear. Here, based on the T-cell epitopes mapped on HTNV glycoprotein, we studied the effects and characteristics of CD4(+)T-cell responses in determining the outcome of hemorrhagic fever with renal syndrome. A total of 79 novel 15-mer T-cell epitopes on the HTNV glycoprotein were identified, among which 20 peptides were dominant target epitopes. Importantly, we showed the presence of both effective Th1 responses with polyfunctional cytokine secretion and ThGranzyme B(+) cell responses with cytotoxic mediators production against HTNV infection. The HTNV glycoprotein-specific CD4(+)T-cell responses inversely correlated with the plasma HTNV RNA load in patients. Individuals with milder disease outcomes showed broader epitopes targeted and stronger CD4(+)T-cell responses against HTNV glycoproteins compared with more severe patients. The CD4(+)T cells characterized by broader antigenic repertoire, stronger polyfunctional responses, better expansion capacity and highly differentiated effector memory phenotype(CD27-CD28-CCR7-CD45RA-CD127(hi)) would elicit greater defense against HTNV infection and lead to much milder outcome of the disease. The host defense mediated by CD4(+)T cells may through the inducing antiviral condition of the host cells and cytotoxic effect of ThGranzyme B+ cells. Thus, these findings highlight the efforts of CD4(+)T-cell immunity to HTNV control and provide crucial information to better understand the immune defense against HTNV infection.

Cytokine response to Hantaan virus infection in patients with hemorrhagic fever with renal syndrome.

Hantaan virus (HTNV) infection of the human body causes a severe acute infectious disease known as hemorrhagic fever renal syndrome (HFRS). The aim of this study was to correlate patient cytokine profiles to HFRS severity. In this study, we discuss the clinical significance of evaluating HFRS treatment outcomes using cytokine information. The levels of 18 cytokines were quantitatively determined in three groups: 34 HTNV IgM+ cases, 63 HTNV IgM- negative cases, and 78 healthy volunteers. The level of 14 serum cytokines were higher in the patient group than that in the healthy control group. In the 34 HTNV IgM+ patient sera, a set of 27 cytokines was further assessed. The cytokines of TNF-ß, IL-1ra, and IL-6 were detected at higher level in the IgM+ group than that in the IgM- group. The deterioration of HFRS was accompanied with multiple cytokines increased, such as IL-1ra, IL-12p70, IL-10, IP-10, IL-17, IL-2, and IL-6. Our data indicate that serum cytokine levels are associated with the progression of HFRS.

Comparison of serological assays to titrate Hantaan and Seoul hantavirus-specific antibodies.

BACKGROUND: Hantaan and Seoul viruses, in the Hantavirus genus, are known to cause hemorrhagic fever with renal syndrome (HFRS). The plaque reduction neutralization test (PRNT), as conventional neutralization test for hantaviruses, is laborious and time-consuming. Alternatives to PRNT for hantaviruses are required. METHODS: In this study, the methods for Hantaan and Seoul viruses serological typing including microneutralization test (MNT), pseudoparticle neutralization test (PPNT) and immunofluorescence assay based on viral glycoproteins (IFA-GP) were developed and compared with PRNT using a panel of 74 sera including 44 convalescent sera of laboratory confirmed HFRS patients and 30 patients sera of non-hantavirus infection. Antibody titres and serotyping obtained with different methods above were analyzed by paired-t, linear correlation, McNemar χ2 and Kappa agreement tests. RESULTS: Antibody titres obtained with MNT50, PPNT50 and IFA-GP were significantly correlated with that obtained with PRNT50 (p < 0.001). GMT determined by PPNT50 was statistically higher than that determined by PRNT50 (p < 0.001), while GMT determined by MNT50 and IFA-GP were equal with (p > 0.05) and less than (p < 0.001) that obtained with PRNT50 respectively. Serotyping obtained with MNT50 and PRNT50, PPNT50 and PRNT50 were highly consistent (p < 0.001), whereas that obtained with IFA-GP and PRNT50 were moderately consistent (p < 0.001). There were no significant differences for serotyping between PRNT50 and MNT50, as well as PRNT50 and PPNT50 (p > 0.05). IFA-GP was less sensitive than PRNT50 and MNT50 for serotyping of hantaviruses infection (p < 0.05). However, for 79.5% (35/44) samples, serotyping determined by IFA-GP and PRNT50 were consistent. CONCLUSIONS: MNT50 and PPNT50 both can be used as simple and rapid alternatives to PRNT50, and MNT50 is more specific while PPNT50 is more sensitive than other assays for neutralizing antibody determination. So far, this work has been the most comprehensive comparison of alternatives to PRNT.

CD8low CD100- T Cells Identify a Novel CD8 T Cell Subset Associated with Viral Control during Human Hantaan Virus Infection.

UNLABELLED: Hantaan virus (HTNV) infection can cause a severe lethal hemorrhagic fever with renal syndrome (HFRS) in humans. CD8(+) T cells play a critical role in combating HTNV infections. However, the contributions of different CD8(+) T cell subsets to the immune response against viral infection are poorly understood. Here, we identified a novel subset of CD8(+) T cells characterized by the CD8(low) CD100(-) phenotype in HFRS patients. The CD8(low) CD100(-) subset accounted for a median of 14.3% of the total CD8(+) T cells in early phase of HFRS, and this percentage subsequently declined in the late phase of infection, whereas this subset was absent in healthy controls. Furthermore, the CD8(low) CD100(-) cells were associated with high activation and expressed high levels of cytolytic effector molecules and exhibited a distinct expression profile of effector CD8(+) T cells (CCR7(+/-) CD45RA(-) CD127(high) CD27(int) CD28(low) CD62L(-)). When stimulated with specific HTNV nucleocapsid protein-derived peptide pools, most responding CD8(+) cells (gamma interferon [IFN-γ] positive and/or tumor necrosis factor alpha [TNF-α] positive) were CD8(low) CD100(-) cells. The frequency of CD8(low) CD100(-) cells among HTNV-specific CD8(+) T cells was higher in milder cases than in more severe cases. Importantly, the proportion of the CD8(low) CD100(-) subset among CD8(+) T cells in early phase of HFRS was negatively correlated with the HTNV viral load, suggesting that CD8(low) CD100(-) cells may be associated with viral clearance. The contraction of the CD8(low) CD100(-) subset in late phase of infection may be related to the consistently high expression levels of PD-1. These results may provide new insights into our understanding of CD8(+) T cell-mediated protective immunity as well as immune homeostasis after HTNV infection in humans. IMPORTANCE: CD8(+) T cells play important roles in the antiviral immune response. We found that the proportion of CD8(low) CD100(-) cells among CD8(+) T cells from HFRS patients was negatively correlated with the HTNV viral load, and the frequency of CD8(low) CD100(-) cells among virus-specific CD8(+) T cells was higher in milder HFRS cases than in more severe cases. These results imply a beneficial role for the CD8(low) CD100(-) cell subset in viral control during human HTNV infection.

History of incomplete vaccination may associate with occurrence of hemorrhagic fever with renal syndrome with relieved clinical symptoms.

OBJECTIVE: This retrospective study is aimed to investigate the clinical features of the patients with history of incomplete vaccination against hemorrhagic fever with renal syndrome (HFRS). METHODS: Data of 140 cases of hospitalized patients with HFRS were collected. The patients were divided into incomplete vaccinated group (n = 10) and unvaccinated group (n = 130) according to vaccination status. Demographic, clinical, and laboratory characteristics of the two groups' patients were compared through t test, Pearson χ(2) test, and Mann-Whitney test. RESULTS: In comparison with the unvaccinated group, the incidence rate of vomiting and hypotensive-shock, the white blood cell (WBC) and platelet count, the level of blood urea nitrogen and albumin, total number of dialysis and hospitalization cost of patients in the incomplete vaccinated group have statistically significant differences. CONCLUSION: HFRS disease may still occur in individuals with a history of HFRS incomplete vaccination although the symptoms may be mild. Effective vaccination against HFRS needs sufficient doses and booster shot of the vaccine.

Detection of Hantaan virus RNA from anti-Hantaan virus IgG seronegative rodents in an area of high endemicity in Republic of Korea.

Hantaan virus (HTNV), of the family Bunyaviridae, causes hemorrhagic fever with renal syndrome (HFRS) in humans. Although the majority of epidemiologic studies have found that rodents are seropositive for hantavirus-specific immunoglobulin, the discovery of hantavirus RNA in seronegative hosts has led to an investigation of the presence of HTNV RNA in rodents captured in HFRS endemic areas. HTNV RNA was detected in seven (3.8%) of 186 anti-HTNV IgG seronegative rodents in Republic of Korea (ROK) during 2013-2014. RT-qPCR for HTNV RNA revealed dynamic virus-host interactions of HTNV in areas of high endemicity, providing important insights into the epidemiology of hantaviruses.

Influence of HLA-DRB alleles on haemorrhagic fever with renal syndrome in a Chinese Han population in Hubei Province, China.

Specific human leucocyte antigen (HLA) alleles are considered a genetic risk factor for the progression of haemorrhagic fever with renal syndrome (HFRS) caused by hantaviruses. The aim of this study was to establish whether HLA-DRB alleles are associated with the severity of HFRS caused by different types of hantaviruses in a Chinese Han population from Hubei Province of central China. Twenty-two specific HLA-DRB alleles were analysed by sequence-specific primer-polymerase chain reaction (SSP-PCR) in 100 HFRS patients and 213 healthy volunteers. Associations of HLA-DRB alleles with the severity and clinical parameters of HFRS caused by Hantaan virus (HTNV) or Seoul virus (SEOV) infection were evaluated. Six alleles (HLA-DRB1*0401-0411, HLA-DRB1*1001, HLA-DRB1*1101-1105, HLA-DRB1*1201-1202, HLA-DRB1*1305 and DRB5*0101-0201) demonstrated strong associations with HFRS caused by HTNV and SEOV infections. Further comparison of these HLA-DRB1 allele frequencies between HFRS patients with differing severities and healthy controls demonstrated that the HLA-DRB1*0401-0411, HLA-DRB1*1001 and DRB1*1305 alleles were more frequent in the moderate course of HTNV-infected HFRS. Meanwhile, the DRB1*1101-1105 allele was more frequently observed in the severe course of HTNV-infected HFRS. We also found that the HLA-DRB1*1201-1202 allele frequency was higher in the moderate course of SEOV-infected HFRS, whereas the DRB5*0101-0201 allele may play a protective role in moderate HFRS caused by both HTNV and SEOV infections. These results provide evidence of the influence of HLA-DRB on the severity of HFRS and confirm the effect of HLA-DRB on HFRS during different types of hantavirus infection in a Chinese Han population in Hubei Province, China.

IFITM-2 and IFITM-3 but not IFITM-1 restrict Rift Valley fever virus.

We show that interferon-induced transmembrane protein 1 (IFITM-1), IFITM-2, and IFITM-3 exhibit a broad spectrum of antiviral activity against several members of the Bunyaviridae family, including Rift Valley fever virus (RVFV), La Crosse virus, Andes virus, and Hantaan virus, all of which can cause severe disease in humans and animals. We found that RVFV was restricted by IFITM-2 and -3 but not by IFITM-1, whereas the remaining viruses were equally restricted by all IFITMs. Indeed, at low doses of alpha interferon (IFN-α), IFITM-2 and -3 mediated more than half of the antiviral activity of IFN-α against RVFV. IFITM-2 and -3 restricted RVFV infection mostly by preventing virus membrane fusion with endosomes, while they had no effect on virion attachment to cells, endocytosis, or viral replication kinetics. We found that large fractions of IFITM-2 and IFITM-3 occupy vesicular compartments that are distinct from the vesicles coated by IFITM-1. In addition, although overexpression of all IFITMs expanded vesicular and acidified compartments within cells, there were marked phenotypic differences among the vesicular compartments occupied by IFITMs. Collectively, our data provide new insights into the possible mechanisms by which the IFITM family members restrict distinct viruses.

Development of an immunochromatography strip test based on truncated nucleocapsid antigens of three representative hantaviruses.

BACKGROUND: Hantaviruses are causative agents of hemorrhagic fever with renal syndrome (HFRS) and nephropathia epidemica (NE) in the Old World and hantavirus pulmonary syndrome (HPS) in the New World. There is a need for time-saving diagnostic methods. In the present study, recombinant N antigens were used as antigens in an immunochromatography strip (ICG) test to detect specific IgG antibodies. METHODS: The N-terminal 103 amino acids (aa) of Hantaan virus (HTNV), Puumala virus (PUUV) and Andes virus (ANDV) nucleocapsid (N) protein were expressed in E. coli as representative antigens of three groups (HFRS, NE and HPS-causing viruses) of hantavirus. Five different types of ICG test strips, one antigen line on one strip for each of the three selected hantaviruses (HTNV, PUUV and ANDV), three antigen lines on one strip and a mixed antigen line on one strip, were developed and sensitivities were compared. RESULTS: A total of 87 convalescent-phase patient sera, including sera from 35 HFRS patients, 36 NE patients and 16 HPS patients, and 25 sera from healthy seronegative people as negative controls were used to evaluate the ICG test. Sensitivities of the three-line strip and mixed-line strip were similar to those of the single antigen strip (97.2 to 100%). On the other hand, all of the ICG test strips showed high specificities to healthy donors. CONCLUSION: These results indicated that the ICG test with the three representative antigens is an effective serodiagnostic tool for screening and typing of hantavirus infection in humans.

T-cell immunoglobulin and mucin 1 (TIM-1) mediates infection of Hantaan virus in Jurkat T cells.

Hantaan virus (HTNV) is a major public health concern due to its ability to cause hemorrhagic fever with renal syndrome (HFRS) in Eurasia. Symptoms of HFRS include fever, hemorrhage, immune dysfunction and renal impairment, and severe cases can be fatal. T cell-mediated adaptive immune responses play a pivotal role in countering HTNV infection. However, our understanding of HTNV and T cell interactions in the disease progression is limited. In this study, we found that human CD4+ T cells can be directly infected with HTNV, thereby facilitating viral replication and production. Additionally, T-cell immunoglobulin and mucin 1 (TIM-1) participated in the process of HTNV infection of Jurkat T cells, and further observed that HTNV enters Jurkat T cells via the clathrin-dependent endocytosis pathway. These findings not only affirm the susceptibility of human CD4+ T lymphocytes to HTNV but also shed light on the viral tropism. Our research elucidates a mode of the interaction between the virus infection process and the immune system. Critically, this study provides new insights into the pathogenesis of HTNV and the implications for antiviral research.

[Infection of human normal lung epithelial cells by Hantaan virus (HTNV) and its impact on innate immunity and metabolism].

Objective To confirm that Hantaan virus (HTNV) can infect BEAS-2B human normal lung epithelial cells and examine the host immune response and metabolic changes induced by HTNV infection by transcriptomic analysis. Methods Western blotting, quantitative real-time PCR and immunofluorescence assay were used to assess the viral load in BEAS-2B cells, and RNA sequencing was employed for transcriptomic analysis. Results Following the infection of BEAS-2B cells with HTNV, there was an increase in the expression of HTNV nucleocapsid protein (NP) and small segment (S) over time. A transcriptomic analysis of these infected cells at 48-hour mark identified 328 genes that were differentially expressed. GO and KEGG enrichment analysis revealed that these differences were primarily associated with interferon response and innate immune pattern recognition receptor pathways. Protein-protein interaction network analysis identified several genes related to innate immune responses, including four genes encoding disintegrin and metalloproteinase with thrombospondin motifs. Metabolic pathway analysis showed three genes related to terpenoid backbone biosynthesis, two genes related to glycolysis/gluconeogenesis and two genes related to steroid hormone biosynthesis. Subcellular localization analysis indicated that many of the differentially expressed genes were located in mitochondria. Conclusion HTNV is capable of effectively infecting BEAS-2B cells, making them a suitable in vitro model for studying HTNV infection in human lung epithelial. By utilizing bioinformatics methods to screen for differentially expressed genes and metabolic pathways associated with HTNV infection, researchers can establish a theoretical foundation for investigating the molecular mechanisms underling HTNV infection.

A recombinant pseudotyped lentivirus expressing the envelope glycoprotein of hantaan virus induced protective immunity in mice.

BACKGROUND: Hantaviruses cause acute hemorrhagic fever with renal syndrome (HFRS). Currently, several types of inactivated HFRS vaccines are widely used, however the limited ability of these immunogen to elicit neutralizing antibodies restricts vaccine efficacy. Development of an effective vaccine to overcome this weakness is must. METHODS: In the present study, a recombinant pseudotyped lentivirus bearing the hantaan virus (HTNV) envelope glycoproteins (GP), rLV-M, was constructed. C57BL/6 mice were immunized with the rLV-M and a series of immunological assays were conducted to determine the immunogenicity of the recombinant pseudotyped lentivirus. The humoral and cell-mediated immune responses induced by rLV-M were compared with those of the inactivated HFRS vaccine. RESULTS: Indirect immunofluorescence assay (IFA) showed the rLV-M expressed target proteins in HEK-293 cells. In mice, the rLV-M efficiently induced GP-specific humoral responses and protection against HTNV infection. Furthermore, the rLV-M induced higher neutralizing antibody titers than the inactivated HFRS vaccine control. CONCLUSIONS: The results indicated the potential of using a pseudotyped lentivirus as a delivery vector for a hantavirus vaccine immunogen.

Identification of a novel B-cell epitope of Hantaan virus glycoprotein recognized by neutralizing 3D8 monoclonal antibody.

Hantaan virus (HTNV), a member of the family Bunyaviridae, is a major agent causing haemorrhagic fever with renal syndrome, a high-mortality-rate disease threatening approximately 150 000 people around the world yearly. The 3D8 mAb displays a neutralizing activity to HTNV infection. In this study, the B-cell epitopes of HTNV glycoproteins (GPs) were finely mapped by peptide scanning. A new B-cell epitope (882)GFLCPEFPGSFRKKC(896) of HTNV, which locates on Gc, has been screened out from a set of 15-mer synthesized peptides covering the full-length of HTNV-GPs. It has been shown by the alanine-scanning technique that (885)C, (893)R, (894)K, (895)K and (896)C are the key amino acids of the binding sites of the GPs. The implications of identifying a novel B-cell epitope for hantavirus immunology and vaccinology are discussed.