Targeting Human Papillomavirus-Associated Cancer by Oncoprotein-Specific Recombinant Antibodies.

In recent decades, recombinant antibodies against specific antigens have shown great promise for the therapy of infectious diseases and cancer. Human papillomaviruses (HPVs) are involved in the development of around 5% of all human cancers and HPV16 is the high-risk genotype with the highest prevalence worldwide, playing a dominant role in all HPV-associated cancers. Here, we describe the main biological activities of the HPV16 E6, E7, and E5 oncoproteins, which are involved in the subversion of important regulatory pathways directly associated with all known hallmarks of cancer. We then review the state of art of the recombinant antibodies targeted to HPV oncoproteins developed so far in different formats, and outline their mechanisms of action. We describe the advantages of a possible antibody-based therapy against the HPV-associated lesions and discuss the critical issue of delivery to tumour cells, which must be addressed in order to achieve the desired translation of the antibodies from the laboratory to the clinic.

Interleukin-17A affects extracellular vesicles release and cargo in human keratinocytes.

Psoriasis is a chronic inflammatory systemic disease caused by deregulation of the interleukin-23/-17 axis that allows the activation of Th17 lymphocytes and the reprogramming of keratinocytes proliferative response, thereby inducing the secretion of cyto-/chemokines and antimicrobial peptides. Beside cell-to-cell contacts and release of cytokines, hormones and second messengers, cells communicate each other through the release of extracellular vesicles containing DNA, RNA, microRNAs and proteins. It has been reported the alteration of extracellular vesicles trafficking in several diseases, but there is scarce evidence of the involvement of extracellular vesicles trafficking in the pathogenesis of psoriasis. The main goal of the study was to characterize the release, the cargo content and the capacity to transfer bioactive molecules of extracellular vesicles produced by keratinocytes following recombinant IL-17A treatment if compared to untreated keratinocytes. A combined approach of standard ultracentrifugation, RNA isolation and real-time RT-PCR techniques was used to characterize extracellular vesicles cargo. Flow cytometry was used to quantitatively and qualitatively analyse extracellular vesicles and to evaluate cell-to-cell extracellular vesicles transfer. We report that the treatment of human keratinocytes with IL-17A significantly modifies the extracellular vesicles cargo and release. Vesicles from IL-17A-treated cells display a specific pattern of mRNA which is undid by IL-17A neutralization. Extracellular vesicles are taken up by acceptor cells irrespective of their content but only those derived from IL-17A-treated cells enable recipient cells to express psoriasis-associated mRNA. The results imply a role of extracellular vesicles in amplifying the pro-inflammatory cascade induced in keratinocyte by pro-psoriatic cytokines.

Human Papillomavirus E6 and E7 oncoproteins affect the cell microenvironment by classical secretion and extracellular vesicles delivery of inflammatory mediators.

The connection between chronic inflammation and risk of cancer has been supported by several studies. The development of cancer might be a process driven by the presence of a specific combination of inflammatory mediators, including cytokines, chemokines and enzymes, in the tumor microenvironment. Virus-induced tumors, like HPV-induced Squamous Cell Carcinomas, represent a paradigmatic example of the interplay between inflammation, as integral part of the innate antiviral response, and malignant transformation. Here, the role of inflammatory microenvironment in the HPV-induced carcinogenesis is addressed, with a specific focus on the involvement of the immune molecules as well as their delivery through the microvesicle cargo possibly correlated to the different HPV genotype. The expression of the inflammatory mediators in HPV positive cells has been analyzed in primary human foreskin keratinocytes and keratinocytes transduced by E6 and E7 from mucosal HPV-16 or cutaneous HPV-38 genotypes. HPV E6 and E7 proteins can modulate the expression of immune mediators in HPV-infected cells and can affect the levels of immune molecules, mainly chemokines, in the extracellular milieu. HPV-16 E6 and E7 oncoproteins have been silenced to confirm the specificity of the modulation of the inflammatory microenvironment. Our results suggest that the expression of HPV oncoproteins allows the modification of the tumor milieu through the synthesis and release of specific pro-inflammatory cytokines and chemokines, affecting the efficacy of the immune response. The microenvironment can also be conditioned by an altered mRNA cargo delivered by extracellular vesicles, thereby efficiently affecting the surrounding cells with possible implication for tumorigenesis and tumor diagnosis.

IFN-ß antiproliferative effect and miRNA regulation in Human Papilloma Virus E6- and E7-transformed keratinocytes.

Human Papilloma Viruses (HPVs) are the causative agents of cervical cancer although other types of cancers are associated with HPV infection. Type I Interferons can interfere with HPV E6- and/or E7-dependent transformation and can affect microRNA (miRNA) expression. Cancer cells show a specific pattern of miRNA expression and HPVs are able to modulate miRNAs expressed in infected cells. Keratinocytes transduced with E6 and E7 from mucosal HPV-16 or cutaneous HPV-38 (K16 and K38) were studied to analyze the involvement of HPV oncoproteins in the anti-proliferative activity of IFN-ß. In view of our previous data showing senescence induction by the cytokine in K38 cells, we observe that IFN-ß treatment leads to p53-indipendent apoptosis in K16 cells whereas induces senescence in K16 cells if E6 is silenced and p53 expression is restored. The levels of selected miRNAs, deregulated in K16 and K38 cells, can be modulated by IFN-ß when E6 and E7 proteins of HPV-16, but not HPV-38, are expressed.

HPV16 Phylogenetic Variants in Anogenital and Head and Neck Cancers: State of the Art and Perspectives.

HPV16 is responsible for approximately 60% and 90% of global HPV-induced cervical and oropharyngeal cancers, respectively. HPV16 intratype variants have been identified by HPV genome sequencing and classified into four phylogenetic lineages (A-D). Our understanding of HPV16 variants mostly derives from epidemiological studies on cervical cancer (CC) in which HPV16 B, C, and D lineages (previously named "non-European" variants) were mainly associated with high-grade cervical lesions and cancer. Although a predominance of HPV16 lineage A (previously named "European variants") has been observed in head and neck squamous cell carcinoma (HNSCC), epidemiological and in vitro biological studies are still limited for this tumor site. Next Generation Sequencing (NGS) of the entire HPV genome has deepened our knowledge of the prevalence and distribution of HPV variants in CC and HNSCC. Research on cervical cancer has shown that certain HPV16 sublineages, such as D2, D3, A3, and A4, are associated with an increased risk of cervical cancer, and sublineages A4, D2, and D3 are linked to a higher risk of developing adenocarcinomas. Additionally, lineage C and sublineages D2 or D3 of HPV16 show an elevated risk of developing premalignant cervical lesions. However, it is still crucial to conduct large-scale studies on HPV16 variants in different HPV-related tumor sites to deeply evaluate their association with disease development and outcomes. This review discusses the current knowledge and updates on HPV16 phylogenetic variants distribution in HPV-driven anogenital and head and neck cancers.

Human Oncogenic Viruses: Characteristics and Prevention Strategies-Lessons Learned from Human Papillomaviruses.

Approximately 12% of human cancers worldwide are associated with infectious agents, which are classified by the International Agency for Research on Cancer (IARC) as Group 1 within the agents that are carcinogenic to humans. Most of these agents are viruses. Group 1 oncogenic viruses include hepatitis C virus, hepatitis B virus (HBV), human T-cell lymphotropic virus type 1, Epstein-Barr virus, Kaposi sarcoma-associated herpesvirus, human immunodeficiency virus-1 and high-risk human papillomaviruses (HPVs). In addition, some human polyomaviruses are suspected of inducing cancer prevalently in hosts with impaired immune responses. Merkel cell polyomavirus has been associated with Merkel cell carcinoma and included by the IARC in Group 2A (i.e., probably carcinogenic to humans). Linking viruses to human cancers has allowed for the development of diagnostic, prophylactic and therapeutic measures. Vaccination significantly reduced tumours induced by two oncogenic viruses as follows: HBV and HPV. Herein, we focus on mucosal alpha HPVs, which are responsible for the highest number of cancer cases due to tumour viruses and against which effective prevention strategies have been developed to reduce the global burden of HPV-related cancers.

Remission of HPV-Related Diseases by Antivirals for Herpesvirus: Clinical Cases and a Literature Review.

Epidemiological studies have shown that HPV-related diseases are the most prevalent sexually transmitted infections. In this context, this report will present various clinical cases demonstrating the effectiveness of Acyclovir (ACV) or its prodrug Valaciclovir (VCV), both acyclic guanosine analogs commonly used for the treatment of HHV-1 and HHV-2, for the treatment of HPV-related diseases. The report shows the remission of five cases of penile condyloma and a case of remission in a woman affected by cervical and vaginal condylomas and a vulvar giant condyloma acuminate of Buschke and Lowenstein. The literature review shows that ACV is effective in treating skin warts when administered orally, topically, and intralesionally, suggesting its therapeutic potential in other diseases associated with HPV. ACV was also used successfully as an adjuvant therapy for juvenile and adult forms of laryngeal papillomatosis, also known as recurrent respiratory papillomatosis, prolonging the patient's symptom-free periods. Although the prevention of HPV infections is certainly achieved with the HPV vaccine, ACV and VCV have shown to be effective even against genotypes not included in the current vaccine and can be helpful for those problematic clinical cases involving unvaccinated individuals, immunocompromised patients, people who live with HIV, or non-responders to the vaccine. We and others concluded that randomized clinical trials are necessary to determine the efficacy of ACV and VCV for HPV-related diseases.

Antibodies Induced by Smallpox Vaccination after at Least 45 Years Cross-React with and In Vitro Neutralize Mpox Virus: A Role for Polyclonal B Cell Activation?

AIMS: To evaluate whether antibodies specific for the vaccinia virus (VV) are still detectable after at least 45 years from immunization. To confirm that VV-specific antibodies are endowed with the capacity to neutralize Mpox virus (MPXV) in vitro. To test a possible role of polyclonal non-specific activation in the maintenance of immunologic memory. METHODS: Sera were collected from the following groups: smallpox-vaccinated individuals with or without latent tuberculosis infection (LTBI), unvaccinated donors, and convalescent individuals after MPXV infection. Supernatant of VV- or MPXV-infected Vero cells were inactivated and used as antigens in ELISA or in Western blot (WB) analyses. An MPXV plaque reduction neutralization test (PRNT) was optimized and performed on study samples. VV- and PPD-specific memory T cells were measured by flow cytometry. RESULTS: None of the smallpox unvaccinated donors tested positive in ELISA or WB analysis and their sera were unable to neutralize MPXV in vitro. Sera from all the individuals convalescing from an MPXV infection tested positive for anti-VV or MPXV IgG with high titers and showed MPXV in vitro neutralization capacity. Sera from most of the vaccinated individuals showed IgG anti-VV and anti-MPXV at high titers. WB analyses showed that positive sera from vaccinated or convalescent individuals recognized both VV and MPXV antigens. Higher VV-specific IgG titer and specific T cells were observed in LTBI individuals. CONCLUSIONS: ELISA and WB performed using supernatant of VV- or MPXV-infected cells are suitable to identify individuals vaccinated against smallpox at more than 45 years from immunization and individuals convalescing from a recent MPXV infection. ELISA and WB results show a good correlation with PRNT. Data confirm that a smallpox vaccination induces a long-lasting memory in terms of specific IgG and that antibodies raised against VV may neutralize MPXV in vitro. Finally, higher titers of VV-specific antibodies and higher frequency of VV-specific memory T cells in LTBI individuals suggest a role of polyclonal non-specific activation in the maintenance of immunologic memory.

Successful therapeutic vaccination with integrase defective lentiviral vector expressing nononcogenic human papillomavirus E7 protein.

Persistent infection with high risk genotypes of human papillomavirus (HPV) is the cause of cervical cancer, one of most common cancer among woman worldwide, and represents an important risk factor associated with other anogenital and oropharyngeal cancers in men and women. Here, we designed a therapeutic vaccine based on integrase defective lentiviral vector (IDLV) to deliver a mutated nononcogenic form of HPV16 E7 protein, considered as a tumor specific antigen for immunotherapy of HPV-associated cervical cancer, fused to calreticulin (CRT), a protein able to enhance major histocompatibility complex class I antigen presentation (IDLV-CRT/E7). Vaccination with IDLV-CRT/E7 induced a potent and persistent E7-specific T cell response up to 1 year after a single immunization. Importantly, a single immunization with IDLV-CRT/E7 was able to prevent growth of E7-expressing TC-1 tumor cells and to eradicate established tumors in mice. The strong therapeutic effect induced by the IDLV-based vaccine in this preclinical model suggests that this strategy may be further exploited as a safe and attractive anticancer immunotherapeutic vaccine in humans.

Conventional therapy for genital herpesvirus and remission of HPV-related lesions: a case series.

This report covers the case of 7 women affected by pathologies related to genital Herpesvirus and Papillomavirus. They were referred to the gynaecology outpatient clinic for colposcopic examination, and received pharmacological antiviral treatment. The patients presented clinical signs of genital Herpesvirus infections in the cervix and vulva. Cervical lesions and condylomatosis, which are characteristic of Papillomavirus infections were also detected, and patients underwent cervical cancer screening. Patients received oral and topical treatment with Acyclovir or oral treatment with Valacyclovir. During weekly or biweekly gynaecological follow-up visits, patients showed different times of remission of genital Herpesvirus. During the antiviral treatments, the vulvar and cervical Papillomavirus lesions also showed complete resolution with restitutio ad integrum of the tissues, and no recurrence at follow-up visits. Herpesvirus and Papillomavirus infections are often associated in genital infections and, as sexual transmitted infections, share the same risk factors. In the cases presented, the observed remission of HPV-related pathologies during Acyclovir and Valaciclovir treatments may suggest that antivirals are also effective in the treatment of HPV lesions. The cases described could pave the way for further investigations and clinical studies.

MicroRNAs Differentially Expressed in Actinic Keratosis and Healthy Skin Scrapings.

Actinic keratosis (AK) is a carcinoma in situ precursor of cutaneous squamous cell carcinoma (cSCC), the second most common cancer affecting the Caucasian population. AK is frequently present in the sun-exposed skin of the elderly population, UV radiation being the main cause of this cancer, and other risk factors contributing to AK incidence. The dysregulation of microRNAs (miRNAs) observed in different cancers leads to an improper expression of miRNA targets involved in several cellular pathways. The TaqMan Array Human MicroRNA Card assay for miRNA expression profiling was performed in pooled AK compared to healthy skin scraping samples from the same patients. Forty-three miRNAs were modulated in the AK samples. The expression of miR-19b (p < 0.05), -31, -34a (p < 0.001), -126, -146a (p < 0.01), -193b, and -222 (p < 0.05) was validated by RT-qPCR. The MirPath tool was used for MiRNA target prediction and enriched pathways. The top DIANA-mirPath pathways regulated by the targets of the 43 miRNAs are TGF-beta signaling, Proteoglycans in cancer, Pathways in cancer, and Adherens junction (7.30 × 10-10 < p < 1.84 × 10-8). Selected genes regulating the KEGG pathways, i.e., TP53, MDM2, CDKN1A, CDK6, and CCND1, were analyzed. MiRNAs modulated in AK regulate different pathways involved in tumorigenesis, indicating miRNA regulation as a critical step in keratinocyte cancer.

Different configurations of SARS-CoV-2 spike protein delivered by integrase-defective lentiviral vectors induce persistent functional immune responses, characterized by distinct immunogenicity profiles.

Several COVID-19 vaccine strategies utilizing new formulations for the induction of neutralizing antibodies (nAbs) and T cell immunity are still under evaluation in preclinical and clinical studies. Here we used Simian Immunodeficiency Virus (SIV)-based integrase defective lentiviral vector (IDLV) delivering different conformations of membrane-tethered Spike protein in the mouse immunogenicity model, with the aim of inducing persistent nAbs against multiple SARS-CoV-2 variants of concern (VoC). Spike modifications included prefusion-stabilizing double proline (2P) substitutions, mutations at the furin cleavage site (FCS), D614G mutation and truncation of the cytoplasmic tail (delta21) of ancestral and Beta (B.1.351) Spike, the latter mutation to markedly improve IDLV membrane-tethering. BALB/c mice were injected once with IDLV delivering the different forms of Spike or the recombinant trimeric Spike protein with 2P substitutions and FCS mutations in association with a squalene-based adjuvant. Anti-receptor binding domain (RBD) binding Abs, nAbs and T cell responses were detected up to six months from a single immunization with escalating doses of vaccines in all mice, but with different levels and kinetics. Results indicated that IDLV delivering the Spike protein with all the combined modifications, outperformed the other candidates in terms of T cell immunity and level of both binding Abs and nAbs soon after the single immunization and persistence over time, showing the best capacity to neutralize all formerly circulating VoC Alpha, Beta, Gamma and Delta. Although present, the lowest response was detected against Omicron variants (BA.1, BA.2 and BA.4/5), suggesting that the magnitude of immune evasion may be related to the higher genetic distance of Omicron as indicated by increased number of amino acid substitutions in Spike acquired during virus evolution.

New Monoclonal Antibodies Specific for Different Epitopes of the Spike Protein of SARS-CoV-2 and Its Major Variants: Additional Tools for a More Specific COVID-19 Diagnosis.

The emergence of the new pathogen SARS-CoV-2 determined a rapid need for monoclonal antibodies (mAbs) to detect the virus in biological fluids as a rapid tool to identify infected individuals to be treated or quarantined. The majority of commercially available antigenic tests for SARS-CoV-2 rely on the detection of N antigen in biologic fluid using anti-N antibodies, and their capacity to specifically identify subjects infected by SARS-CoV-2 is questionable due to several structural analogies among the N proteins of different coronaviruses. In order to produce new specific antibodies, BALB/c mice were immunized three times at 20-day intervals with a recombinant spike (S) protein. The procedure used was highly efficient, and 40 different specific mAbs were isolated, purified and characterized, with 13 ultimately being selected for their specificity and lack of cross reactivity with other human coronaviruses. The specific epitopes recognized by the selected mAbs were identified through a peptide library and/or by recombinant fragments of the S protein. In particular, the selected mAbs recognized different linear epitopes along the S1, excluding the receptor binding domain, and along the S2 subunits of the S protein of SARS-CoV-2 and its major variants of concern. We identified combinations of anti-S mAbs suitable for use in ELISA or rapid diagnostic tests, with the highest sensitivity and specificity coming from proof-of-concept tests using recombinant antigens, SARS-CoV-2 or biological fluids from infected individuals, that represent important additional tools for the diagnosis of COVID-19.

Simian immunodeficiency virus-Vpx for improving integrase defective lentiviral vector-based vaccines.

BACKGROUND: Integrase defective lentiviral vectors (IDLV) represent a promising delivery system for immunization purposes. Human dendritic cells (DC) are the main cell types mediating the immune response and are readily transduced by IDLV, allowing effective triggering of in vitro expansion of antigen-specific primed CD8+ T cells. However, IDLV expression in transduced DC is at lower levels than those of the integrase (IN) competent counterpart, thus requiring further improvement of IDLV for future use in the clinic. RESULTS: In this paper we show that the addition of simian immunodeficiency (SIV)-Vpx protein in the vector preparation greatly improves transduction of human and simian DC, but not of murine DC, thus increasing the ability of transduced DC to act as functional antigen presenting cells, in the absence of integrated vector sequences. Importantly, the presence of SIV-Vpx allows for using lower dose of input IDLV during in vitro transduction, thus further improving the IDLV safety profile. CONCLUSIONS: These results have significant implications for the development of IDLV-based vaccines.

The E6 and E7 proteins of beta3 human papillomavirus 49 can deregulate both cellular and extracellular vesicles-carried microRNAs.

BACKGROUND: The ß3 human papillomavirus (HPV)49 induces immortalization of primary keratinocytes through the action of E6 and E7 oncoproteins with an efficiency similar to alpha high risk (HR)-HPV16. Since HR-HPV oncoproteins are known to alter microRNA (miRNA) expression and extracellular vesicle (EV) production, we investigated the impact of HPV49 E6 and E7 proteins on miRNA profile and EV expression, and their involvement in the control of cell proliferation. METHODS: The miRNA expression was evaluated by a miRNA array and validated by RT-qPCR in primary human keratinocytes immortalized by ß3 HPV49 (K49) or α9 HR-HPV16 (K16), and in EVs from K49 and K16. The modulation of miRNA target proteins was investigated by immunoblotting analyses. RESULTS: By comparing miRNA expression in K49 and K16 and the derived EVs, six miRNAs involved in HPV tumorigenesis were selected and validated. MiR-19a and -99a were found to be upregulated and miR-34a downregulated in both cell lines; miR-17 and -590-5p were upregulated in K49 and downmodulated in K16; miR-21 was downregulated only in K16. As for EV-carried miRNAs, the expression of miR-17, -19a, -21 and -99a was decreased and miR-34a was increased in K49 EVs. In K16 EVs, we revealed the same modulation of miR-19a, -34a, and -99a observed in producing cells, while miR-21 was upregulated. Cyclin D1, a common target of the selected miRNAs, was downmodulated in both cell lines, whereas cyclin-dependent kinase 4 was down-modulated in K49 but upregulated in K16. CONCLUSION: These data suggest that E6 and E7 proteins of ß3 HPV49 and α9 HR-HPV16 affect key factors of cell cycle control by indirect mechanisms based on miRNA modulation.

Prevalence of 13 polyomaviruses in actinic keratosis and matched healthy skin samples of immunocompetent individuals.

BACKGROUND: Actinic keratosis (AK) is a precursor of cutaneous squamous cell carcinoma (cSCC). UV radiation is the major risk factor for AK, but certain human papillomaviruses (HPVs) of the beta genus are also involved in its development. Differently, the role of polyomaviruses (PyVs) in skin carcinogenesis is still debated. Fiftheen PyVs have been isolated from human tissues so far, including Merkel cell polyomavirus (MCPyV), the aetiological agent of Merkel cell carcinoma. METHODS: The presence of 13 PyVs was assessed in skin samples from AK patients (n = 342). Matched fresh-frozen scrapings from healthy skin (HS) and AK lesions from 242 patients, and formalin-fixed paraffin-embedded AK biopsies from a different cohort of 100 patients were analyzed by multiplex PyVs genotyping assay. RESULTS: The most frequent lesion site was the scalp in men (27.3%), and the cheek area in women (29.0%). Differences between men and women were significant for the scalp, the cheek area and the lips. Almost all the scrapings were PyV-positive (HS: 89.7%, AK: 94.6%; p = 0.04). The three most frequent PyVs were MCPyV, HPyV6 and JCPyV (HS: 87.2%, 58.7%, 6.6%, respectively; AK: 88.8%, 51.2%, 9.9%, respectively). HPyV9, TSPyV, BKPyV, HPyV7, LIPyV and SV40 were detected in < 2% of the scrapings. In most cases, matched HS and AK scrapings were both positive (MCPyV: 78.1%, HPyV6: 41.7%), or both negative for the individual genotypes (for the remaining PyVs). PyV prevalence in AK biopsies was 22.0%. Only MCPyV (21.0%) and HPyV6 (3.0%) were detected in these samples. CONCLUSIONS: PyV prevalence in HS and AK scrapings was high, but detection of PyVs exclusively in AK scrapings was rare. PyV positivity rate in AK biopsies was modest. Further research is need to reach firm conclusions regarding the role of these viruses in AK development.

Virus-Induced Tumorigenesis and IFN System.

Oncogenic viruses favor the development of tumors in mammals by persistent infection and specific cellular pathways modifications by deregulating cell proliferation and inhibiting apoptosis. They counteract the cellular antiviral defense through viral proteins as well as specific cellular effectors involved in virus-induced tumorigenesis. Type I interferons (IFNs) are a family of cytokines critical not only for viral interference but also for their broad range of properties that go beyond the antiviral action. In fact, they can inhibit cell proliferation and modulate differentiation, apoptosis, and migration. However, their principal role is to regulate the development and activity of most effector cells of the innate and adaptive immune responses. Various are the mechanisms by which IFNs exert their effects on immune cells. They can act directly, through IFN receptor triggering, or indirectly by the induction of chemokines, the secretion of further cytokines, or by the stimulation of cells useful for the activation of particular immune cells. All the properties of IFNs are crucial in the host defense against viruses and bacteria, as well as in the immune surveillance against tumors. IFNs may be affected by and, in turn, affect signaling pathways to mediate anti-proliferative and antiviral responses in virus-induced tumorigenic context. New data on cellular and viral microRNAs (miRNAs) machinery, as well as cellular communication and microenvironment modification via classical secretion mechanisms and extracellular vesicles-mediated delivery are reported. Recent research is reviewed on the tumorigenesis induced by specific viruses with RNA or DNA genome, belonging to different families (i.e., HPV, HTLV-1, MCPyV, JCPyV, Herpesviruses, HBV, HCV) and the IFN system involvement.

Isolation and Characterization of Mouse Monoclonal Antibodies That Neutralize SARS-CoV-2 and Its Variants of Concern Alpha, Beta, Gamma and Delta by Binding Conformational Epitopes of Glycosylated RBD With High Potency.

Antibodies targeting Receptor Binding Domain (RBD) of SARS-CoV-2 have been suggested to account for the majority of neutralizing activity in COVID-19 convalescent sera and several neutralizing antibodies (nAbs) have been isolated, characterized and proposed as emergency therapeutics in the form of monoclonal antibodies (mAbs). However, SARS-CoV-2 variants are rapidly spreading worldwide from the sites of initial identification. The variants of concern (VOC) B.1.1.7 (Alpha), B.1.351 (Beta), P.1 (Gamma) and B.1.167.2 (Delta) showed mutations in the SARS-CoV-2 spike protein potentially able to cause escape from nAb responses with a consequent reduction of efficacy of vaccines and mAbs-based therapy. We produced the recombinant RBD (rRBD) of SARS-CoV-2 spike glycoprotein from the Wuhan-Hu 1 reference sequence in a mammalian system, for mice immunization to isolate new mAbs with neutralizing activity. Here we describe four mAbs that were able to bind the rRBD in Enzyme-Linked Immunosorbent Assay and the transmembrane full-length spike protein expressed in HEK293T cells by flow cytometry assay. Moreover, the mAbs recognized the RBD in supernatants of SARS-CoV-2 infected VERO E6 cells by Western Blot under non-reducing condition or in supernatants of cells infected with lentivirus pseudotyped for spike protein, by immunoprecipitation assay. Three out of four mAbs lost their binding efficiency to completely N-deglycosylated rRBD and none was able to bind the same recombinant protein expressed in Escherichia coli, suggesting that the epitopes recognized by three mAbs are generated by the conformational structure of the glycosylated native protein. Of particular relevance, three mAbs were able to inhibit Wuhan SARS-CoV-2 infection of VERO E6 cells in a plaque-reduction neutralization test and the Wuhan SARS-CoV-2 as well as the Alpha, Beta, Gamma and Delta VOC in a pseudoviruses-based neutralization test. These mAbs represent important additional tools for diagnosis and therapy of COVID-19 and may contribute to the understanding of the functional structure of SARS-CoV-2 RBD.

Human Papillomavirus and carcinogenesis: Novel mechanisms of cell communication involving extracellular vesicles.

A small group of mucosal Human Papillomaviruses are the causative agents of cervical cancer and are also associated with other types of cancers. Certain cutaneous Human Papillomaviruses seem to have a role as co-factors in the UV-induced carcinogenesis of the skin. The main mechanism of the tumorigenesis induced by Human Papillomaviruses is linked to the transforming activity of the viral E6 and E7 oncoproteins. However, other mechanisms, such as the gene expression control by specific microRNAs expression and deregulation of immune inflammatory mediators, may be important in the process of transformation. In this context, the release of Extracellular Vesicles with a specific cargo (microRNAs involved in tumorigenesis, mRNAs of viral oncoproteins, cytokines, chemokines) appears to play a key role.

Detection of human papillomaviruses in paired healthy skin and actinic keratosis by next generation sequencing.

Actinic keratosis (AK) arises on photo-damaged skin and is considered to be the precursor lesion of cutaneous squamous cell carcinoma (cSCC). Many findings support the involvement of ß human papillomaviruses (HPVs) in cSCC, while very little is known on γ HPV types. The objective of this study was to characterize the spectrum of PV types in healthy skin (HS) and AK samples of the same immunocompetent individuals using next generation sequencing (NGS). Viral DNA of 244 AK and 242 HS specimens were amplified by PCR using two different sets of primers (FAP59/64 and FAPM1). Purified amplicons were pooled and sequenced using NGS. The study resulted in the identification of a large number of known ß and γ PV types. In addition, 27 putative novel ß and 16 γ and 4 unclassified PVs were isolated. HPV types of species γ-1 (e.g. HPV4) appeared to be strongly enriched in AK versus HS. The NGS analysis revealed that a large spectrum of known and novel PVs is present in HS and AK. The evidence that species γ-1 HPV types appears to be enriched in AK in comparison to HS warrants further studies to evaluate their role in development of skin (pre)cancerous lesions.