Cells In Infection Research Articles

Severe respiratory viral infections: T-cell functions diverging from immunity to inflammation.

Respiratory viral infections such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza A virus (IAV) trigger distinct clinical outcomes defined by immunity-based viral clearance or disease associated with exaggerated and prolonged inflammation. The important role of T cells in shaping both antiviral immunity and inflammation has revived interest in understanding the host-pathogen interactions that lead to the diverse functions of T cells in respiratory viral infections. Inborn deficiencies and acquired insufficiency in immunity can prolong infection and shift the immune response towards exacerbated inflammation, which results from persistent innate immune activation and bystander T-cell activation that is nonspecific to the pathogen but is often driven by cytokines. This review discusses how virus variants, exposure doses, routes of infection, host genetics, and immune history can modulate the activation and function of T cells, thus influencing clinical outcomes. Knowledge of virus-host interaction can inform strategies to prevent immune dysfunction in respiratory viral infection and help in the treatment of associated diseases.

WS07.05 Unraveling the pathogenicity of Mycobacterium abscessus clinical isolates in cystic fibrosis pulmonary epithelial cell and mouse models of respiratory infection

Mycobacterium abscessus (Mabs) infections can be caused by strains belonging to different dominant circulating clones (DCCs) or displaying bacterial morphotypes in people with cystic fibrosis (CF).

A scientific perspective of how and why Omicron is less severe than SARS-CoV-2

Abstract Omicron is currently the dominant variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the coronavirus responsible for the coronavirus disease 2019 (COVID-19) pandemic. Omicron is associated with mild symptoms, although it can cause harmful effects in high-risk patient populations. Omicron and COVID-19 affect multiple organ systems, including the respiratory system, gastrointestinal tract, cardiovascular system, central nervous system, ophthalmic system, genitourinary tract, and musculoskeletal system. COVID-19 infects additional organ systems, including the hematological system, hepatobiliary system, renal system, and dermatologic system. The viral-induced complications were compared to discuss the effects of Omicron versus the authentic SARS-CoV-2 virus, revealing less detrimental outcomes for Omicron. Moreover, COVID-19 is more likely to infect older adults, males, and obesity with mild to severe symptoms. Omicron causes mild symptoms in younger populations and overweight females. Data were acquired using PubMed, Centers for Disease Prevention and Control, and the World Health Organization. COVID-19 and Omicron mechanisms causing organ system-related complications are likely because of the natural immune response to the active infection, the uncontrollable release of cytokines causing cytokine release syndrome, and direct viral damage through angiotensin-converting enzyme 2/transmembrane serine protease 2 receptor binding and entrance to the host cell for infection.

A fast Fibonacci wavelet-based numerical algorithm for the solution of HIV-infected cells model.

In this article, we present a novel approach under the Fibonacci wavelet and collocation technique which is computationally efficient to obtain the solution of the model of cells of HIV infection. A system of nonlinear ordinary differential equations represents this mathematical model. We have approximated unknown functions and their derivatives using the operational matrix of integration of Fibonacci wavelets to transform this model into a set of algebraic equations and then simplified using a suitable method. It is anticipated that the proposed approach would be more efficient and suitable for solving a variety of nonlinear ordinary and partial differential equations representing the model of medical, radiation, and surgical oncology, and drug targeting systems that occur in medical science and engineering. Tables and graphs are included to show how the suggested wavelet method provides enhanced accuracy for a wide range of problems. Relative data and computations are performed over MATLAB software.

Tonic TNF conditioning of macrophages safeguards stimulus‐specific inflammatory responses

Tumor necrosis factor (TNF) is a key inflammatory cytokine that warns recipient cells of a nearby infection or tissue damage. Acute exposure to TNF activates characteristic oscillatory dynamics of the transcription factor NFκB and induces a characteristic gene expression program; these are distinct from the responses of cells directly exposed to pathogen‐associated molecular patterns (PAMPs). Here, we report that tonic TNF exposure is critical for safeguarding TNF's specific functions. In the absence of tonic TNF conditioning, acute exposure to TNF causes (i) NFκB signaling dynamics that are less oscillatory and more like PAMP‐responsive NFκB dynamics, (ii) immune gene expression that is more similar to the Pam3CSK4 response program, and (iii) broader epigenomic reprogramming that is characteristic of PAMP‐responsive changes. We show that the absence of tonic TNF signaling effects subtle changes to TNF receptor availability and dynamics such that enhanced pathway activity results in non‐oscillatory NFκB. Our results reveal tonic TNF as a key tissue determinant of the specific cellular responses to acute paracrine TNF exposure, and their distinction from responses to direct exposure to PAMPs.

The role of regulatory T cells and follicular T helper cells in HBV infection.

Hepatitis B has become one of the major global health threats, especially in developing countries and regions. Hepatitis B virus infection greatly increases the risk for liver diseases such as cirrhosis and cancer. However, treatment for hepatitis B is limited when considering the huge base of infected people. The immune response against hepatitis B is mediated mainly by CD8+ T cells, which are key to fighting invading viruses, while regulatory T cells prevent overreaction of the immune response process. Additionally, follicular T helper cells play a key role in B-cell activation, proliferation, differentiation, and formation of germinal centers. The pathogenic process of hepatitis B virus is generally the result of a disorder or dysfunction of the immune system. Therefore, we present in this review the critical functions and related biological processes of regulatory T cells and follicular T helper cells during HBV infection.

Intercellular communication within the virus microenvironment affects the susceptibility of cells to secondary viral infections.

Communication between infected cells and cells in the surrounding tissue is a determinant of viral spread. However, it remains unclear how cells in close or distant proximity to an infected cell respond to primary or secondary infections. We establish a cell-based system to characterize a virus microenvironment, distinguishing infected, neighboring, and distal cells. Cell sorting, microscopy, proteomics, and cell cycle assays allow resolving cellular features and functional consequences of proximity to infection. We show that human cytomegalovirus (HCMV) infection primes neighboring cells for both subsequent HCMV infections and secondary infections with herpes simplex virus 1 and influenza A. Neighboring cells exhibit mitotic arrest, dampened innate immunity, and altered extracellular matrix. Conversely, distal cells are poised to slow viral spread due to enhanced antiviral responses. These findings demonstrate how infection reshapes the microenvironment through intercellular signaling to facilitate spread and how spatial proximity to an infection guides cell fate.

Folliculin Prevents Lysosomal Degradation of Human Papillomavirus To Support Infectious Cell Entry.

Human papillomavirus (HPV) infects epithelial basal cells in the mucosa and either proliferates with the differentiation of the basal cells or persists in them. Multiple host factors are required to support the HPV life cycle; however, the molecular mechanisms involved in cell entry are not yet fully understood. In this study, we performed a genome-wide clustered regularly interspaced short palindromic repeat (CRISPR)-CRISPR-associated protein 9 (Cas9) knockout (KO) screen in HeLa cells and identified folliculin (FLCN), a GTPase-activating protein for Rag GTPases, as an important host factor for HPV infection. The introduction of single guide RNAs for the FLCN gene into HeLa, HaCaT, and ectocervical Ect1 cells reduced infection by HPV18 pseudovirions (18PsVs) and 16PsVs. FLCN KO HeLa cells also exhibited strong resistance to infection with 18PsVs and 16PsVs; nevertheless, they remained highly susceptible to infections with vesicular stomatitis virus glycoprotein-pseudotyped lentivirus and adeno-associated virus. Immunofluorescence microscopy revealed that the numbers of virions binding to the cell surface were slightly increased in FLCN KO cells. However, virion internalization analysis showed that the internalized virions were rapidly degraded in FLCN KO cells. This degradation was blocked by treatment with the lysosome inhibitor bafilomycin A1. Furthermore, the virion degradation phenotype was also observed in Ras-related GTP-binding protein C (RagC) KO cells. These results suggest that FLCN prevents the lysosomal degradation of incoming HPV virions by enhancing lysosomal RagC activity. IMPORTANCE Cell entry by human papillomavirus (HPV) involves a cellular retrograde transport pathway from the endosome to the trans-Golgi network/Golgi apparatus. However, the mechanism by which this viral trafficking is safeguarded is poorly understood. This is the first study showing that the GTPase-activating protein folliculin (FLCN) protects incoming HPV virions from lysosomal degradation and supports infectious cell entry by activating the Rag GTPases, presumably through the suppression of excessive lysosomal biosynthesis. These findings provide new insights into the effects of small GTPase activity regulation on HPV cell entry and enhance our understanding of the HPV degradation pathway.

Role of B Cells in Mycobacterium Tuberculosis Infection.

Historically, research on the immunologic response to Mycobacterium tuberculosis (M. tb) infection has focused on T cells and macrophages, as their role in granuloma formation has been robustly characterized. In contrast, the role of B cells in the pathophysiology of M. tb infection has been relatively overlooked. While T cells are well-known as an essential for granuloma formation and maintenance, B cells play a less understood role in the host response. Over the past decade, scarce research on the topic has attempted to elucidate the varying roles of B cells during mycobacterial infection, which appears to be primarily time dependent. From acute to chronic infection, the role of B cells changes with time as evidenced by cytokine release, immunological regulation, and histological morphology of tuberculous granulomas. The goal of this review is to carefully analyze the role of humoral immunity in M. tb infection to find the discriminatory nature of humoral immunity in tuberculosis (TB). We argue that there is a need for more research on the B-cell response against TB, as a better understanding of the role of B cells in defense against TB could lead to effective vaccines and therapies. By focusing on the B-cell response, we can develop new strategies to enhance immunity against TB and reduce the burden of disease.

Herpes Simplex Virus Type 1 Induces AD-like Neurodegeneration Markers in Human Progenitor and Differentiated ReNcell VM Cells.

An increasing body of evidence strongly suggests that infections or reactivations of herpes simplex virus type 1 (HSV-1) may be closely linked to Alzheimer's disease (AD). Promising results have been obtained using cell and animal models of HSV-1 infection, contributing to the understanding of the molecular mechanisms linking HSV-1 infection and AD neurodegeneration. ReNcell VM is a human neural stem cell line that has been used as a model system to study the impact of various infectious agents on the central nervous system. In this study, we demonstrate the suitability of the ReNcell VM cell line for developing a new in vitro model of HSV-1 infection. By following standard differentiation protocols, we were able to derive various nervous cell types, including neurons, astrocytes, and oligodendrocytes, from neural precursors. Additionally, we demonstrated the susceptibility of ReNcell VM cells, including precursor and differentiated cells, to HSV-1 infection and subsequent viral-induced AD-like neurodegeneration. Our findings support the use of this cell line to generate a new research platform for investigating AD neuropathology and its most significant risk factors, which may lead to important discoveries in the context of this highly impactful disease.

Host factor TNK2 is required for influenza virus infection.

Host factors are required for Influenza virus infection and have great potential to become antiviral target. Here we demonstrate the role of TNK2 in influenza virus infection. CRISPR/Cas9 induced TNK2 deletion in A549 cells. CRISPR/Cas9-mediated deletion of TNK2. Western blotting and qPCR was used to measure the expression of TNK2 and other proteins. CRISPR/Cas9-mediated deletion of TNK2 decreased the replication of influenza virus and significantly inhibited the ex-pression of viral proteins and TNK2 inhibitors (XMD8-87 and AIM-100) reduced the expression of influenza M2, while over-expression of TNK2 weakened the resistance of TNK2-knockout cells to influenza virus infection. Furthermore, a decrease of nuclear import of IAV in the infected TNK2 mutant cells was observed in 3h post-infection. Interestingly, TNK2 deletion enhanced the colocalization of LC3 with autophagic receptor p62 and led to the attenuation of influenza virus-caused accumulation of autophagosomes in TNK2 mutant cells. Further, confocal microscopy visualization result showed that influenza viral matrix 2 (M2) was colocalized with Lamp1 in the infected TNK2 mutant cells in early infection, while almost no colocalization between M2 and Lamp1 was observed in IAV-infected wild-type cells. Moreover, TNK2 depletion also affected the trafficking of early endosome and the movement of influenza viral NP and M2. Our results identified TNK2 as a critical host factor for influenza viral M2 protein trafficking, suggesting that TNK2 will be an attractive target for the development of antivirals therapeutics.

Role of CXCR5+ CD8+ T cells in human hepatitis B virus infection.

The replication of HBV in hepatocytes can be effectively inhibited by lifelong antiviral therapy. Because of the long-term presence of HBV reservoirs, the virus rebound frequently occurs once the treatment is stopped, which poses a considerable obstacle to the complete removal of the virus. In terms of gene composition, regulation of B cell action and function, CXCR5+ CD8+ T cells are similar to CXCR5+ CD4+ T follicular helper cells, while these cells are characterized by elevated programmed cell death 1 and cytotoxic-related proteins. CXCR5+ CD8+ T cells are strongly associated with progression in inflammatory and autoimmune diseases. In addition, CXCR5 expression on the surface of CD8+ T cells is mostly an indicator of memory stem cell-like failure in progenitor cells in cancer that are more responsive to immune checkpoint blocking therapy. Furthermore, the phenomena have also been demonstrated in some viral infections, highlighting the duality of the cellular immune response of CXCR5+ CD8+ T cells. This mini-review will focus on the function of CXCR5+ CD8+ T cells in HBV infection and discuss the function of these CD8+ T cells and the potential of associated co-stimulators or cytokines in HBV therapeutic strategies.

Lactobacillus johnsoniisupplementation modulates functional response of bone-marrow derived dendritic cells in respiratory allergy and viral infection

Abstract The immunomodulatory properties of probiotics are particularly important at the establishment of Th 1-Th 2immune balance early in life. A skewing to Th 2immune response driven by dendritic cell regulation can lead to airway alteration during respiratory allergy and respiratory virus infection. Previous work from our lab have determined that oral supplementation of mice with Lactobacillus johnsonii (Lj) resulted to be protective against viral and allergen airway exposure. In order to further analyze whether Lj supplementation of moms could alter offspring responses to allergic disease, female mice were supplemented daily with Lj for a week before mating. Allergen-sensitized offspring from Lj supplemented-mothers were protected from airway hyperreactivity, had a diminished mucus production and shown a reduced allergen-restimulated Th 2cytokine response upon later life allergen-induced responses. Maternal Lj supplementation changed the functional response of bone-marrow derived dendritic cells (BMDC) activated in vitro with respiratory syncytial virus (RSV), decreased expression of pathological cytokines and chemokines in non-sensitized pups, but increased protective innate cytokines expression in allergic offspring. Neonates supplemented directly with Lj before early life RSV infection altered long term inflammatory activity of BMDC by reducing expression of proinflammatory innate cytokines. These results have shown the immunomodulatory potential of Lj supplementation during pre- and post-natal periods to protect from allergic and viral immune responses in distal mucosal surfaces by altering systemic immune cell responses. RO1HL144858

TZANCK SMEAR: A USEFUL DIAGNOSTIC TOOL IN SPECTRUM OF VESICULOBULLOUS DISEASES OF SKIN.

Introduction: The pemphigus group of autoimmune bullous disorders and mucocutaneous herpesvirus infections are generally diagnosed with the Tzanck smear. Only a few research have looked into its diagnostic value in the literature. To evaluate tzanck smear ndings in patients Objectives: with vesiculobullous skin lesions and histopathological correlation. All recei Material and Methods: ved Samples received between 01/08/2021 to 31/01/2022 were stained with May-Grunwald-Giemsa. In some patients, methylene blue staining and ZN staining were done. Tzanck Results: smear was performed on a total of 25 patients with skin lesions. The sensitivities of multinucleated giant cells and acantholytic cells in herpetic infections, dyskeratotic acantholytic cells,inammatory cells and cocci in bullous impetigo, acantholytic cells with neutrophils and lymphocytes in pemphigus foliaceous, acantholytic cells and plenty of neutrophils in drug-induced pemphigus, no acantholytic cells with neutrophils and lymphocytes in IgA pemphigus, cluster of acantholytic cells in pemphigus vulgaris, only lymphocytes with no acantholytic cells in bullous pemphigoid and dyskeratotic acantholytic cells without inammation in staphylococcal scalded skin syndrome, intracytoplasmic HendersonPatterson bodies and anucleated squamous cells in molluscum contagiosum and broblast, leucocytes with necrotic basal cells in Toxic epidermal necrolysis. The tzanck smear test is an inexpensive, useful, quick, reliable Conclusion: and an easy diagnostic tool for certain vesiculobullous skin diseases.

Effect of estrogen signaling in CD8 T cell mediated antiviral response

Abstract Estrogen, the major female sex hormone has been linked with immune response disparity between males and females. However, the exact mechanism by which estrogen impacts our ability to fight viral infection and development of immunologic memory remains unknown. CD8 T cells represent the primary protective mechanism against viruses and cancer. Here we aim to understand how CD8 T cell mediated antiviral immune response is regulated by estrogen. Systemic LCMV infection in ovariectomized female mice generated lower virus-specific memory CD8 T cells compared to sham surgery controls. To check if this reduction in memory response is CD8 T cell intrinsic, I generated a transgenic virus-specific estrogen receptor-α deficient CD8 mouse line (ESR1 KO). Using a co-adoptive transfer model, I compared the differentiation of ESR1 KO and control CD8 T cells in both systemic LCMV and local influenza infection. The lack of estrogen signaling resulted in reduced abundance of effector CD8 T cells in the context of both infections. ESR1 KO CD8 T cells also displayed reduced cytotoxic ability. In vitrostudies revealed that the CD8 T cell expansion was primarily impacted by the lack of estrogen signaling, whereas activation and cellular apoptosis remain unchanged. Altogether, this suggests a crucial role of sex steroid estrogen in initial effector CD8 T cell differentiation, that has significant ramification for generation of protective immune responses in pathological or physiological estrogen deficiency. Supported by grants from Searle Scholars Foundation, NIH 2P20GM109035, NIH P20GM121298, NIH T32HL134625, NIH T32GM136566

Characterizing the effect of type I interferon signaling within regulatory T cells in HSV-2 infection

Abstract Herpes simplex virus type-2 (HSV-2) is a lifelong, recurrent sexually transmitted infection that affects about 13% of the world population between ages 13–49. There is currently no available vaccine for HSV-2 and understanding the nuances of cell-mediated immunity is crucial to developing improved therapeutics and vaccines. HSV-2 infection induces a potent, localized type I interferon (TIIFN) signaling cascade that can stimulate both innate and adaptive antiviral effector responses. Interestingly, regulatory T cells (Tregs), an immunosuppressive CD4+ T cell subset, also respond to TIIFNs. TIIFNs have previously been shown to transiently inhibit Tregs early during a systemic lymphocytic choriomeningitis virus (LCMV) infection to promote the development of antiviral CD4+ and CD8+ T cell responses, and Tregs that lack the interferon alpha receptor (IFNAR) have enhanced suppressive function. The role of TIIFNs in a mucosal infection such as HSV-2 is unclear and studying the tissue-specific effects of TIIFNs warrants further study. To investigate the role of TIIFN signaling within Tregs in the context of HSV-2, we infected IFNARfl/fl x FoxP3Cre mice intravaginally with attenuated or WT HSV-2 and assessed phenotypic Treg markers and viral titers within the vaginal tract by flow cytometry and plaque assays, respectively. Preliminary data indicates that WT, and not attenuated HSV-2 infected mice show enhanced disease progression and increased viral titers. This suggests that TIIFN signaling in Tregs could be aiding in mediating protection early in HSV-2 infection. NIH R01AI141435

Adrenergic receptors regulate T cell differentiation in viral infection and cancer

Abstract CD8 +T cells are critical components of the immune reaction against viral infections and cancer and have the potential to eliminate infected or malignant cells. However, when the antigen persists, CD8 +T cells enter an exhausted state. Chronic disease can lead to increased systemic noradrenaline (NA) levels, but it is currently still unclear how NA impacts the differentiation and function of exhausted CD8 +T cells. We here set out to characterize the effects of β adrenergic signaling on CD8 +T cells in chronic viral infection with LCMV-clone 13 and in murine cancer models. We observed that chronically infected mice had elevated systemic NA levels and CD8 +T cells expressed higher levels of the β-1 adrenergic NA receptor, Adrb1. NA impaired T cell receptor signaling of ADRB1-expressing CD8 +T cells, and reduced T cell proliferation and function. Conversely, genetic ablation of ADRB1 prevented terminal CD8 +T cell differentiation in chronic viral infection and ADRB1-blockade enhanced T cell functionality in combination with immune checkpoint blockade (ICB) in an ICB-sensitive melanoma model. Expanding these observations to an ICB-resistant model of pancreatic cancer, we found that pharmacological blockade of adrenergic receptors synergized with ICB to genetically reprogram CD8 +T cells towards a tissue resident memory T cell-like state and improved T cell functionality, resulting in decreased tumor size. In summary, our data suggest that β adrenergic receptors represent a novel immune checkpoint that modulates CD8 +T cell differentiation and function in the context of chronic antigen exposure and that targeting adrenergic receptors may synergize with ICB in cancer patients. AMG was supported by the German Research Foundation (Deutsche Forschungsgemeinschaft, GL 991/1-1). SZ was supported by K00CA222741. This work was supported by grants from the NIH 5 R01 CA240909 (SMK) and 5 R01 CA216101 (SMK).

Chronic LCMV infection regulates the effector T cell response by inducing the generation of less immunogenic dendritic cells

Chronic viral infection impairs systemic immunity in the host; however, the mechanism underlying the dysfunction of immune cells in chronic viral infection is incompletely understood. In this study, we studied the lineage differentiation of hematopoietic stem cells (HSCs) during chronic viral infection to elucidate the changes in dendritic cell (DC) differentiation and subsequent impact on T cell functionality using a chronic lymphocytic choriomeningitis virus (LCMV) infection model. We first investigated the lineage differentiation of HSCs in the bone marrow (BM) to elucidate the modulation of immune cell differentiation and found that the populations highly restrained in their differentiation were common myeloid progenitors (CMPs) and common dendritic cell progenitors (CDPs). Of interest, the main immune cells infected with LCMV Clone 13 (CL13) in the BM were CD11b/c+ myeloid DCs. We next characterized CD11b+ DCs that differentiated during chronic LCMV infection. These DCs displayed a less immunogenic phenotype than DCs in naive or acutely infected mice, showing low expression of CD80 but high expression of PD-L1, B7-H4, IDO, TGF-β, and IL-10. Consequently, these CD11b+ DCs induced less effective CD8+ T cells and more Foxp3+ regulatory T (Treg) cells. Furthermore, CD11b+ DCs generated during CL13 infection could not induce effective CD8+ T cells specific to the antigens of newly invading pathogens. Our findings demonstrate that DCs generated from the BM during chronic viral infection cannot activate fully functional effector CD8+ T cells specific to newly incoming antigens as well as persistent antigens themselves, suggesting a potential cause of the functional alterations in the T cell immune response during chronic viral infection.

Investigating the Distinct Tissue Repair and Immunosuppressive Roles of Regulatory T cells in HSV-2 Infection

Abstract Herpes Simplex Virus 2 (HSV-2) is the primary cause of genital herpes, affecting 500 million people worldwide of which approximately 64% are women. Despite this disproportionately high burden, the female reproductive tract and its unique mucosal immune environment is surprisingly understudied. Tregs are necessary for CD4 +T cell priming in the draining lymph node (dLN), though their role in shaping tissue-resident memory T cell (T rm) responses during HSV-2 reactivation is unclear. Our preliminary data indicate that activated Tregs accumulate and persist in mouse vaginal tissue (VT) after above baseline out to at least 90 days post-infection (p.i.), thus implicating Tregs in memory recall responses to reinfection. We hypothesize that Tregs restrain robust T rmrecall responses to HSV-2 challenge. Additionally, we hypothesize that vaginal Tregs promote tissue healing in the VT in response to inflammatory alarmins through the expression of the epidermal growth factor ligand, amphiregulin (Areg). Female FoxP3 DTRmice were infected intravaginally with attenuated HSV-2, then systemically depleted of Tregs via intraperitoneal injection of diphtheria toxin and challenged with WT HSV-2 on day 30 p.i. Systemically Treg-depleted mice show increased activation and proliferation of T cells, and increased frequency of cytotoxic HSV-2-specific CD8 +T cells in the VT by day 3 post-challenge. Treg-depleted mice also have significantly higher pathology scores in H&E-stained VT. We also report that VT Tregs from infected mice express more Areg than dLN Tregs via flow cytometry and single cell RNAseq. Ongoing work includes characterization of Areg expressing VT Tregs and further dissection of the T rmrecall responses in Treg-depleted mice. NIH (T32 AI07140, R01 AI141435)

Highly pathogenic porcine reproductive and respiratory syndrome virus-induced inflammatory response in porcine pulmonary microvascular endothelial cells and effects of herbal ingredients on main inflammatory molecules

The role of microvascular endothelial cells (MVECs) in viral infection has received increasing attention. Our previous study demonstrated the susceptibility of porcine pulmonary MVECs to highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV), while their responses to the viral infection remain unclear. This study aimed to understand effects of the HP-PRRSV infection on functions of porcine pulmonary MVECs and the intervention effects of Chinese herbal ingredients on them. Highly purified porcine pulmonary MVECs were separated using CD31-immunomagnetic beads and infected with HP-PRRSV JXA1 and HN strain. The virus particles in cells and the ultrastructural pathological changes of cells were revealed by transmission electron microscopy. High-throughput transcriptome sequencing indicated that 104 and 228 genes were differentially expressed at 36h post-infection, respectively, including many inflammatory molecules such as interleukins, chemokines, and adhesion molecules. The expression kinetics of HP-PRRSV-induced IL-1α, IL-6, IL-8, and VCAM-1 were characterized at the mRNA and protein levels. Luteolin significantly down-regulated HP-PRRSV-induced increase of the four molecules at both levels, and glycyrrhetinic acid and baicalin reduced that of IL-6 and VCAM-1. Our results suggest that porcine pulmonary MVECs play important roles in the inflammatory lung injury caused by HP-PRRSV infection and that herbal ingredients have potential regulatory effects on the HP-PRRSV-induced dysfunction of MVECs.