Molecular Characterization of Human Papillomavirus Type 159 (HPV159)

Human papillomavirus type 159 (HPV159) was identified in an anal swab sample and preliminarily genetically characterized by our group in 2012. Here we present a detailed molecular in silico analysis that showed that the HPV159 viral genome is 7443 bp in length and divided into five early and two late genes, with conserved functional domains and motifs, and a non-coding long control region (LCR) with significant regulatory sequences that allow the virus to complete its life cycle and infect novel host cells. HPV159, clustering into the cutaneotropic Betapapillomavirus (Beta-PV) genus, is phylogenetically most similar to HPV9, forming an individual phylogenetic group in the viral species Beta-2. After testing a large representative collection of clinical samples with HPV159 type-specific RT-PCR, in addition to the anal canal from which the first HPV159 isolate was obtained, HPV159 was further detected in other muco-cutaneous (4/181, 2.2%), mucosal (22/764, 2.9%), and cutaneous (14/554, 2.5%) clinical samples, suggesting its extensive tissue tropism. However, because very low HPV159 viral loads were estimated in the majority of positive samples, it seemed that HPV159 mainly caused clinically insignificant infections of the skin and mucosa. Using newly developed, highly sensitive HPV159-specific nested PCRs, two additional HPV159 LCR viral variants were identified. Nevertheless, all HPV159 mutations were demonstrated outside important functional domains of the LCR, suggesting that the HPV159 viral variants were most probably not pathogenically different. This complete molecular characterization of HPV159 enhances our knowledge of the genome characteristics, tissue tropism, and phylogenetic diversity of Beta-PVs that infect humans.     

Vaccine-Relevant Human Papillomavirus (HPV) Infections and Future Acquisition of High-Risk HPV Types in Men

Background.Little is known about type-specific associations between prevalent human papillomavirus (HPV) infections and risk of acquiring other HPV types in men. Data on natural clustering of HPV types are needed as a prevaccine distribution to which postvaccine data can be compared. Methods.Using data from a randomized controlled trial of male circumcision in Kisumu, Kenya, adjusted mean survival ratios were estimated for acquisition of any-HPV, high-risk (HR) HPV, and individual HR-HPV types among men uninfected as compared to those infected with vaccine-relevant HPV types 16, 18, 31, 45, 6, or 11 at baseline. Results.Among 1097 human immunodeficiency virus-negative, uncircumcised men, 2303 incident HPV infections were detected over 2534 person-years of follow-up. Although acquisition of individual HR-HPV types varied by baseline HPV type, there was no clear evidence of shorter times to acquisition among men without vaccine-relevant HPV-16, -18, -31, -45, -6, or -11 infections at baseline, as compared to men who did have these infections at baseline. Conclusions.These prospective data on combinations of HPV infections over time do not suggest the potential for postvaccination HPV type replacement. Future surveillance studies are needed to definitely determine whether elimination of HPV types by vaccination will alter the HPV type distribution in the population.     

Distribution of Human Papillomavirus (HPV) Genotypes in HIV-Negative and HIV-Positive Women with Cervical Intraepithelial Lesions in the Eastern Cape Province,South Africa

South African women have a high rate of cervical cancer cases, but there are limited data on human papillomavirus (HPV) genotypes in cervical intraepithelial neoplasia (CIN) in the Eastern Cape province, South Africa. A total of 193 cervical specimens with confirmed CIN from women aged 18 years or older, recruited from a referral hospital, were tested for HPV infection. The cervical specimens, smeared onto FTA cards, were screened for 36 HPV types using an HPV direct flow kit. HPV prevalence was 93.5% (43/46) in CIN2 and 96.6% (142/147) in CIN3. HIV-positive women had a significantly higher HPV prevalence than HIV-negative women (98.0% vs. 89.1%, p = 0.012). The prevalence of multiple types was significantly higher in HIV-positive than HIV-negative women (p = 0.034). The frequently detected genotypes were HPV35 (23.9%), HPV58 (23.9%), HPV45 (19.6%), and HPV16 (17.3%) in CIN2 cases, while in CIN3, HPV35 (22.5%), HPV16 (21.8%), HPV33 (15.6%), and HPV58 (14.3%) were the most common identified HPV types, independent of HIV status. The prevalence of HPV types targeted by the nonavalent HPV vaccine was 60.9% and 68.7% among women with CIN2 and CIN3, respectively, indicating that vaccination would have an impact both in HIV-negative and HIV-positive South African women, although it will not provide full protection in preventing HPV infection and cervical cancer lesions.     

Immune responses in hepatitis C virus infection and mechanisms of hepatitis C virus persistence

Immune responses against hepatitis C virus (HCV) play a crucial role in the pathogenesis of chronic hepatitis C. HCV infection often persists and leads to chronic hepatitis and eventually cirrhosis. Accumulated data suggest that HCV proteins suppress host immune responses through the suppression of functions of immune cells, such as cytotoxic T lymphocytes, natural killer cells, and dendritic cells. They also suppress the type 1 interferon signaling system. The resulting insufficient immune responses against HCV lead to the sustained infection. The appropriate control of immune responses would contribute to the eradication of HCV and the improvement of hepatitis, but there are still many issues to be clarified. This review describes the scientific evidence to support these emerging concepts, and will touch on the implications for improving antiviral therapy.     

Characterization of CD56-/CD16+ natural killer (NK) cells: a highly dysfunctional NK subset expanded in HIV-infected viremic individuals

Natural killer (NK) cells are an important component of the innate immune response against viral infections. NK cell-mediated cytolytic activity is defective in HIV-infected individuals with high levels of viral replication. In the present study, we examined the phenotypic and functional characteristics of an unusual CD56(-)/CD16(+) (CD56(-)) NK subset that is greatly expanded in HIV-viremic individuals. The higher level of expression of inhibitory NK receptors and the lower level of expression of natural cytotoxicity receptors observed in the CD56(-) NK fraction compared with that of CD56(+) NK cells was associated with extremely poor in vitro cytotoxic function of this subset. In addition, the secretion of certain cytokines known to be important in initiating antiviral immune responses was markedly reduced in the CD56(-), as compared with the CD56(+) NK cell subset. These data suggest that the expansion of this highly dysfunctional CD56(-) NK cell subset in HIV-viremic individuals largely accounts for the impaired function of the total NK cell population.     

A recombinant bispecific single-chain Fv antibody against HLA class II and FcgammaRIII (CD16) triggers effective lysis of lymphoma cells

Bispecific antibodies offer the possibility of improving effector-cell recruitment for antibody therapy. For this purpose, a recombinant bispecific single-chain Fv antibody (bsscFv), directed against FcgammaRIII (CD16) and human leucocyte antigen (HLA) class II, was constructed and tested in functional assays. RNA from the hybridomas 3G8 and F3.3, reacting with CD16 and HLA class II, respectively, was used to generate phage display libraries. From these libraries, reactive phages were isolated and the bsscFv was constructed by connecting both single-chain Fv components through a 20 amino acid flexible linker. After expression in SF21 insect cells and chromatographic purification, the bsscFv bound specifically and simultaneously to both antigens. The affinities of the anti-CD16 and the anti-HLA class II scFv components of the bsscFv were 8.6 x 10(-8) mol/l and 13.7 x 10(-8) mol/l, respectively, which was approximately sevenfold lower than the F(ab) fragments of the parental antibodies. In antibody-dependent cellular cytotoxicity experiments with human mononuclear cells as effectors, the bsscFv-mediated specific lysis of both HLA class II-positive, malignant human B-lymphoid cell lines and primary cells from patients with chronic B-cell lymphocytic leukaemia. Optimal lysis was obtained at bsscFv concentrations of approximately 400 ng/ml, similar to the concentration required for maximum lysis by the corresponding chemically linked bispecific antibody. Thus, this recombinant bsscFv-antibody is an efficient molecule for effector-cell mediated lysis of malignant human B-lymphoid cells.     

Exploring the Role of Innate Lymphocytes in the Immune System of Bats and Virus-Host Interactions

Bats are reservoirs of a large number of viruses of global public health significance, including the ancestral virus for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the causative agent of coronavirus disease 2019 (COVID-19). Although bats are natural carriers of multiple pathogenic viruses, they rarely display signs of disease. Recent insights suggest that bats have a more balanced host defense and tolerance system to viral infections that may be linked to the evolutionary adaptation to powered flight. Therefore, a deeper understanding of bat immune system may provide intervention strategies to prevent zoonotic disease transmission and to identify new therapeutic targets. Similar to other eutherian mammals, bats have both innate and adaptive immune systems that have evolved to detect and respond to invading pathogens. Bridging these two systems are innate lymphocytes, which are highly abundant within circulation and barrier tissues. These cells share the characteristics of both innate and adaptive immune cells and are poised to mount rapid effector responses. They are ideally suited as the first line of defense against early stages of viral infections. Here, we will focus on the current knowledge of innate lymphocytes in bats, their function, and their potential role in host–pathogen interactions. Moreover, given that studies into bat immune systems are often hindered by a lack of bat-specific research tools, we will discuss strategies that may aid future research in bat immunity, including the potential use of organoid models to delineate the interplay between innate lymphocytes, bat viruses, and host tolerance.     

不同证型活动期与缓解期溃疡性结肠炎患者自然杀伤T细胞的表达差异研究

[目的]探讨自然杀伤T细胞（NKT）在不同证型活动期与缓解期溃疡性结肠炎（UC）患者中的差异表达及其临床意义.[方法]将UC患者分为以下4组：湿热型活动期组（A）、湿热型缓解期组（B）、脾肾阳虚型活动期组（C）、脾肾阳虚型缓解期组（D）,各25例;选取20例行肠镜检查的健康体检者作为对照组.采集以上5组的外周血及结肠黏膜组织,采用流式细胞术检测NKT及其细胞因子γ干扰素（IFN-γ）和肿瘤坏死因子α（TNF-α）的频率.[结果]①NKT：外周血及结肠频率均呈现A＜B＜C＜D的顺序,且A显著低于B,C显著低于D,A显著低于C,B显著低于D（均P＜0.05）;每组结肠NKT频率均显著低于外周血（P＜0.05）.②细胞因子：外周血与结肠频率大体呈现A＜B＜C＜D,且组间差异有统计学意义,且每组结肠NKT频率均显著低于外周血（P＜0.05）.[结论]NKT及其细胞因子频率降低在湿热证型及活动期UC发病机制中起到关键作用.     

The p36 Isoform of Murine Cytomegalovirus m152 Protein Suffices for Mediating Innate and Adaptive Immune Evasion

The MHC-class I (MHC-I)-like viral (MHC-Iv) m152 gene product of murine cytomegalovirus (mCMV) was the first immune evasion molecule described for a member of the β-subfamily of herpesviruses as a paradigm for analogous functions of human cytomegalovirus proteins. Notably, by interacting with classical MHC-I molecules and with MHC-I-like RAE1 family ligands of the activatory natural killer (NK) cell receptor NKG2D, it inhibits presentation of antigenic peptides to CD8 T cells and the NKG2D-dependent activation of NK cells, respectively, thus simultaneously interfering with adaptive and innate immune recognition of infected cells. Although the m152 gene product exists in differentially glycosylated isoforms whose individual contributions to immune evasion are unknown, it has entered the scientific literature as m152/gp40, based on the quantitatively most prominent isoform but with no functional justification. By construction of a recombinant mCMV in which all three N-glycosylation sites are mutated (N61Q, N208Q, and N241Q), we show here that N-linked glycosylation is not essential for functional interaction of the m152 immune evasion protein with either MHC-I or RAE1. These data add an important functional detail to recent structural analysis of the m152/RAE1γ complex that has revealed N-glycosylations at positions Asn61 and Asn208 of m152 distant from the m152/RAE1γ interface.     

Depo Medroxyprogesterone (DMPA) Promotes Papillomavirus Infections but Does Not Accelerate Disease Progression in the Anogenital Tract of a Mouse Model

Contraceptives such as Depo-medroxyprogesterone (DMPA) are used by an estimated 34 million women worldwide. DMPA has been associated with increased risk of several viral infections including Herpes simplex virus-2 (HSV-2) and Human immunodeficiency virus (HIV). In the current study, we used the mouse papillomavirus (MmuPV1) anogenital infection model to test two hypotheses: (1) contraceptives such as DMPA increase the susceptibility of the anogenital tract to viral infection and (2) long-term contraceptive administration induces more advanced disease at the anogenital tract. DMPA treatments of both athymic nude mice and heterozygous NU/J (Foxn1^nu/+) but ovariectomized mice led to a significantly increased viral load at the anogenital tract, suggesting that endogenous sex hormones were involved in increased viral susceptibility by DMPA treatment. Consistent with previous reports, DMPA treatment suppressed host anti-viral activities at the lower genital tract. To test the impact of long-term contraceptive treatment on the MmuPV1-infected lower genital tract, we included two other treatments in addition to DMPA: 17β-estradiol and a non-hormone based contraceptive Cilostazol (CLZ, Pletal). Viral infections were monitored monthly up to nine months post infection by qPCR. The infected vaginal and anal tissues were harvested and further examined by histological, virological, and immunological analyses. Surprisingly, we did not detect a significantly higher grade of histology in animals in the long-term DMPA and 17β-estradiol treated groups when compared to the control groups in the athymic mice we tested. Therefore, although DMPA promotes initial papillomavirus infections in the lower genital tract, the chronic administration of DMPA does not promote cancer development in the infected tissues in our mouse model.     

Role of the Immune System in Hypertension: Modulation by Dietary Antioxidants

Hypertension is a major health problem worldwide. Individuals with hypertension are at an increased risk for stroke, heart disease, and kidney failure. Although the etiology of essential hypertension has a genetic component, lifestyle factors such as diet play an important role. Insulin resistance is a common feature of hypertension in both humans and animal models affecting glucose and lipid metabolism producing excess aldehydes including methylglyoxal. These aldehydes react with proteins to form conjugates called advanced glycation end products (AGEs). This alters protein structure and function and can affect vascular and immune cells leading to their activation and secretion of inflammatory cytokines. AGEs also act via receptors for advanced glycation end products on these cells altering the function of antioxidant and metabolic enzymes, and ion channels. This results in an increase in cytosolic free calcium, decrease in nitric oxide, endothelial dysfunction, oxidative stress, peripheral vascular resistance, and infiltration of vascular and kidney tissue with inflammatory cells leading to hypertension. Supplementation with dietary antioxidants including vitamins C, E, or B₆, thiols such as cysteine and lipoic acid, have been shown to lower blood pressure and plasma inflammatory cytokines in animal models and humans with essential hypertension. A well-balanced diet rich in antioxidants that includes vegetables, fruits, low fat dairy products, low salt, and includes whole grains, poultry, fish and nuts, lowers blood pressure and vascular inflammation. These antioxidants may achieve their antihypertensive and anti-inflammatory/immunomodulatory effects by reducing AGEs and improving insulin resistance and associated alterations. Dietary supplementation with antioxidants may be a beneficial, inexpensive, front-line alterative treatment modality for hypertension.     

Enhanced cytotoxic function of natural killer and natural killer T‐like cells associated with decreased CD94 (Kp43) in the chronic obstructive pulmonary disease airway

Background and objective: Natural killer (NK) and natural killer T (NKT)‐like cells represent a small but important proportion of effector lymphocytes that we have previously shown to be major sources of pro‐inflammatory cytokines and granzymes. We hypothesized that these cells would be increased in the airway in chronic obstructive pulmonary disease (COPD), accompanied by reduced expression of the inhibitory receptor CD94 (Kp43) and increased expression of cytotoxic mediators granzyme B and perforin. Methods: We measured NK and NKT‐like cells and their expression of CD94 in the blood of COPD patients (n = 71; 30 current and 41 ex‐smokers), smokers (16) and healthy controls (25), and bronchoalveolar lavage fluid (BALF) from a cohort of subjects (19 controls, 12 smokers, 33 COPD). Activation was assessed by measuring CD69 in blood and the cytotoxic potential of NK cells by measuring granzymes A and B, and using a cytotoxicity assay in blood and BALF. Results: In blood in COPD, there were no significant changes in the proportion of NK or NKT‐like cells or expression of granzyme A or NK cytotoxic potential versus controls. There was, however, increased expression of granzyme B and decreased expression of CD94 by both cell types versus controls. The proportion of NK and NKT‐like cells were increased in BALF in COPD, associated with increased NK cytotoxicity, increased expression of granzyme B and decreased expression of the inhibitory receptor CD94 by both cell types. Conclusions: Treatment strategies that target NK and NKT‐like cells, their cytotoxicity and production of inflammatory mediators in the airway may improve COPD morbidity.     

Negative regulation of liver regeneration by innate immunity (natural killer cells/interferon-gamma)

BACKGROUND AND AIMS: Hepatic lymphocytes are composed mainly of natural killer (NK) cells and NKT cells, which play key roles in innate immune responses against pathogens and tumors in the liver. This report analyzes the effects of activation of innate immunity by viral infection or the toll-like receptor 3 (TLR3) ligand on liver regeneration. METHODS: The partial hepatectomy (PHx) method was used as a model of liver regeneration. Murine cytomegalovirus (MCMV) infection and the TLR3 ligand polyinosinic-polycytidylic acid [poly(I:C)] were used to activate innate immunity. RESULTS: NK cells are activated after PHx, as evidenced by producing interferon (IFN)-gamma. Infection with MCMV or injection of poly(I:C) further activates NK cells to produce IFN-gamma and attenuates liver regeneration in the PHx model. Depletion of NK cells or disruption of either the IFN-gamma gene or the IFN-gamma receptor gene enhances liver regeneration and partially abolishes the negative effects of MCMV and polyI:C on liver regeneration, whereas NKT cells may only play a minor role in suppression of liver regeneration. Adoptive transfer of IFN-gamma +/+ NK cells, but not IFN-gamma -/- NK cells, restores the ability of polyI:C to attenuate liver regeneration in NK-depleted mice. Finally, administration of polyI:C or IFN-gamma enhances expression of several antiproliferative proteins, including STAT1, IRF-1, and p21cip1/waf1 in the livers of partially hepatectomized mice. CONCLUSIONS: Our findings suggest that viral infection and the TLR3 ligand negatively regulate liver regeneration via activation of innate immunity (NK/IFN-gamma), which may play an important role in the pathogenesis of viral hepatitis.     

Filaria/Wolbachia activation of dendritic cells and development of Th1-associated responses is dependent on Toll-like receptor 2 in a mouse model of ocular onchocerciasis (river blindness)

Toll-like receptors (TLRs) regulate dendritic cell function and activate signals that mediate the nature of the adaptive immune response. The current study examined the role of TLRs in dendritic cell activation and in regulating T cell and antibody responses to antigens from the filarial parasites Onchocerca volvulus and Brugia malayi, which cause river blindness and lymphatic filariasis, respectively. Bone-marrow-derived CD11c(+) cells from C57BL/6 and TLR4(-/-) mice produced high levels of IL-6 and RANTES, and showed elevated surface CD40 expression, whereas CD11c(+) cells from myeloid differentiation factor 88(-/-) (MyD88(-/-)), TLR2(-/-) and TLR2/4(-/-) mice were not activated. Similarly, IFN-gamma production by splenocytes from immunized TLR2(-/-) mice was significantly impaired compared with splenocytes from C57BL/6 and TLR4(-/-) mice. In contrast, there was no difference among these strains in Th2-associated responses including IL-5 production by splenocytes from immunized animals, serum IgE and IgG(1), or eosinophil infiltration into the corneal stroma. Neutrophil recruitment to the cornea and CXC chemokine production was inhibited in immunized TLR2(-/-) mice compared with C57BL/6 and TLR4(-/-) mice. Taken together, these findings demonstrate an essential role for TLR2 in filaria-induced dendritic cell activation, IFN-gamma production and neutrophil migration to the cornea, but does not affect filaria-induced Th2-associated responses.     

Effective lysis of lymphoma cells with a stabilised bispecific single-chain Fv antibody against CD19 and FcgammaRIII (CD16)

A recombinant bispecific single-chain fragment variable antibody (bsscFv), directed against the B-cell antigen CD19 and the low affinity Fc-receptor FcgammaRIII (CD16), was designed for use in the treatment of patients with leukaemias and lymphomas. The Fc-portions of whole antibodies were deliberately eliminated in this construct to avoid undesired effector functions. A stabilised bsscFv, ds[CD19 x CD16], was generated, in which disulphide bonds bridging the respective variable light (VL) and variable heavy (VH) chains were introduced into both component single-chain (sc)Fvs. After production in 293T cells and chromatographic purification, ds[CD19 x CD16] specifically and simultaneously bound both antigens. The serum stability of ds[CD19 x CD16] was increased more than threefold when compared with the unstabilised counterpart, while other biological properties were not affected by these mutations. In antibody-dependent cellular cytotoxicity experiments, ds[CD19 x CD16] mediated specific lysis of both CD19-positive malignant human B-lymphoid cell lines and primary tumour cells from patients with B-cell chronic lymphocytic leukaemia or B-cell acute lymphoblastic leukaemia. Natural killer cells, mononuclear cells (MNCs) from healthy donors and, in some instances, MNCs isolated from patients after allogeneic stem cell transplantation, were used as effectors. Thus, ds[CD19 x CD16] holds promise for the treatment of CD19(+) B-lineage malignancies.     

Immaturity of IL-18 gene expression and protein production in cord blood (CB) versus peripheral blood (PB) mononuclear cells and differential effects in natural killer (NK) cell development and function

We have previously demonstrated dysregulation of IL-12 and IL-15 gene and protein expression between activated cord blood (CB) versus peripheral blood (PB) mononuclear cells (MNCs). In the present study, we compared IL-18 gene expression and protein production and IL-18 mRNA half-life in basal versus activated CB versus PB MNCs, the effects of IL-18 +/- IL-12 on MNCs IFN-gamma protein production and ex vivo expansion and activation of CB with IL-12 + IL-2 + anti-CD3 +/- IL-18. Basal and activated levels of IL-18 were significantly higher in PB versus CB MNCs (P < 0.05). IL-18 mRNA was coincidental with protein levels and significantly lower in CB (P < 0.05) and its half-life significantly shorter in CB versus PB MNCs (P < 0.05). IL-18 synergistically with IL-12 induced IFN-gamma production from PB greater than CB MNCs (P < 0.05). NK cells expansion (P < 0.001) and cytotoxicity (P < 0.01) was significantly increased with IL-12 + IL-2 + anti-CD3 and IL-18. In summary IL-18 gene expression and protein production are significantly decreased in activated CB versus PB MNCs, in part secondary to increased degradation of CB IL-18 mRNA. These results may have implications for the mechanism(s) in part responsible for the immaturity of CB T-cell immunity.     

Differential IFN‐γ production by adult and neonatal blood CD56+ natural killer (NK) and NK‐like‐T cells in response to Trypanosoma cruzi and IL‐15

Early interferon‐gamma (IFN‐γ) release by innate cells is critical to direct type 1 immune response able to control intracellular pathogens like Trypanosoma cruzi. Although CD56^bright natural killer (NK) cells are reported to be potent early IFN‐γ producers, other CD56⁺ cells like CD56^dim NK cells and NK‐like T cells have recently been shown to also release IFN‐γ. We have here studied the contribution of each CD56⁺ lymphocyte populations in early IFN‐γ production in both adults and neonates. On this purpose, we analysed the kinetics of IFN‐γ production by RT‐PCR, ELISA and flow cytometry from 2 h onwards after T. cruzi and IL‐15 stimulation and sought for the responding CD56⁺ cells. CD56^bright and CD56^dimCD16^? NK cells were the more potent IFN‐γ early producers in response to IL‐15 and parasites in adults and neonates. In both age groups, the majority of IFN‐γ producing cells were NK cells. However, on the contrary to neonates, CD3⁺CD56⁺ NK‐like T cells and CD3⁺CD56^? ‘classical’ T cells also contributed to early IFN‐γ production in adults. Altogether, our results support that whereas NK cells responded almost similarly in neonates and adults, cord blood innate CD56⁺ and CD56^? T cells displayed major quantitative and qualitative defects that could contribute to the well‐known neonatal immune immaturity.