Immunobiology of HPV Infection

The HPV viral regulatory mechanism of TLRs and the related treatments for HPV-associated cancers

Infection with human papillomavirus (HPV) typically leads to cervical cancer, skin related cancers and many other tumors. HPV is mainly responsible for evading immune tumor monitoring in HPV related cancers. Toll like receptors (TLRs) are particular pattern recognition molecules. When the body is facing immune danger, it can lead to innate and direct adaptive immunity. TLR plays an important role in initiating antiviral immune responses. HPV can affect the expression level of TLR and interfere with TLR related signaling pathways, resulting in sustained viral infection and even carcinogenesis. This paper introduces the HPV virus and HPV related cancers. We discussed the present comprehension of TLR, its expression and signaling, as well as its role in HPV infection. We also provided a detailed introduction to immunotherapy methods for HPV related diseases based on TLR agonists. This will provide insights into methods that support the therapeutic method of HPV related conditions with TLR agonists.

Epidemiology, Molecular Pathogenesis, Immuno-Pathogenesis, Immune Escape Mechanisms and Vaccine Evaluation for HPV-Associated Carcinogenesis

Human papillomavirus (HPV) is implicated in over 90% of cervical cancer cases, with factors like regional variability, HPV genotype, the population studied, HPV vaccination status, and anatomical sample collection location influencing the prevalence and pathology of HPV-induced cancer. HPV-16 and -18 are mainly responsible for the progression of several cancers, including cervix, anus, vagina, penis, vulva, and oropharynx. The oncogenic ability of HPV is not only sufficient for the progression of malignancy, but also for other tumor-generating steps required for the production of invasive cancer, such as coinfection with other viruses, lifestyle factors such as high parity, smoking, tobacco chewing, use of contraceptives for a long time, and immune responses such as stimulation of chronic stromal inflammation and immune deviation in the tumor microenvironment. Viral evasion from immunosurveillance also supports viral persistence, and virus-like particle-based prophylactic vaccines have been licensed, which are effective against high-risk HPV types. In addition, vaccination awareness programs and preventive strategies could help reduce the rate and incidence of HPV infection. In this review, we emphasize HPV infection and its role in cancer progression, molecular and immunopathogenesis, host immune response, immune evasion by HPV, vaccination, and preventive schemes battling HPV infection and HPV-related cancers.

TLR4 and SARM1 modulate survival and chemoresistance in an HPV-positive cervical cancer cell line

Human Papillomavirus is responsible for a wide range of mucosal lesions and tumors. The immune system participate in tumorigenesis in different ways. For example, signaling pathways triggered by Toll-like receptors (TLR) play a role in chemotherapy resistance in several tumor types and are candidates for contributing to the development of HPV-induced tumors. Here, we studied the receptor TLR4 and the adaptor molecule SARM1 in HeLa cells, an HPV-positive cervical cancer cell line. Knocking out of these genes individually proved to be important for maintaining cell viability and proliferation. TLR4 knock out cells were more sensitive to cisplatin treatment, which was illustrated by an increased frequency of apoptotic cells. Furthermore, TLR4 and SARM1 modulated ROS production, which was induced by cell death in response to cisplatin. In conclusion, TLR4 and SARM1 are important for therapy resistance and cervical cancer cell viability and may be relevant clinical targets.

An Update on Human Papilloma Virus Vaccines: History, Types, Protection, and Efficacy

Human papillomavirus (HPV) is the most common sexually transmitted agent worldwide. Early prevention with HPV vaccination is a safe and effective method against this disease. HPV vaccines provided more protection against several oncogenic HPV strains. Three prophylactic HPV vaccines have been approved to target high-risk HPV types and protect against HPV-related disorders. These existing vaccines are based on the recombinant DNA technology and purified L1 protein that is assembled to form HPV empty shells. The prophylactic vaccines are highly immunogenic and can induce production of specific neutralizing antibodies. However, therapeutic vaccines are different from these prophylactic vaccines. They induced cell-mediated immunity against transformed cells, instead of neutralizing antibodies. The second generation of prophylactic HPV vaccines, made from alternative viral components using cost-effective production strategies, is undergoing clinical evaluation. The purpose of this review is to provide a complete and up-to-date review of the types of HPV vaccines and the efficiency of each of them for readers.

A meta-analysis of association of Human Leukocyte Antigens A, B, C, DR and DQ with Human Papillomavirus 16 infection

Human Papillomavirus (HPV) induced cervical cancer (CaCx) is a major health problem in women from both developing and developed regions of the world. This virus accounts for >95% of the CaCx cases with a preponderance of HPV type -16 (65%). Paradoxically HPV-16 is prevalent even in the cervix of healthier women and anti HPV-16 T-cell response is considered critical for the viral clearance. Studies on HLA association with HPV-16 infection and cervical cancer have yielded varied HLA associations in different epidemiological settings. To validate these associations, we performed a meta-analysis of HLA-A, B, C, DR and DQ association with HPV-16 infection. Of the 1409 studies retrieved, 26 qualified for meta-analysis based on stringent inclusion and exclusion criteria. HLA-B*47, B*57, DRB1*10, DRB1*15 and DQB1*0303 were significantly associated with HPV-16 infection (OR = 3.4, 1.8, 1.5, 1.1 and 1.5 respectively). HLA-B*49, B*39, A28 (serotype), C*04 and DRB1*13 were negatively associated with HPV-16 (OR = 0.5, 0.6, 0.7, 0.7, and 0.7 respectively). Certain HLA alleles such as B*07, DRB1*15, DRB1*11 and DRB1*07 showed weakly positive associations. A comprehensive analysis coupling HPV-16 antigenic diversity and the HLA variation in various global populations shall provide further insights into the immunogenetic predisposition to HPV-16 and shall help identify host-parasite co-evolution.

HPV-transformed cells exhibit altered HMGB1-TLR4/MyD88-SARM1 signaling axis

Cervical cancer is one of the leading causes of cancer death in women worldwide. Persistent infection with high-risk human papillomavirus (HPV) types is the main risk factor for the development of cervical cancer precursor lesions. HPV persistence and tumor development is usually characterized by innate immune system evasion. Alterations in Toll-like receptors (TLR) expression and activation may be important for the control of HPV infections and could play a role in the progression of lesions and tumors. In the present study, we analyzed the mRNA expression of 84 genes involved in TLR signaling pathways. We observed that 80% of the differentially expressed genes were downregulated in cervical cancer cell lines relative to normal keratinocytes. Major alterations were detected in genes coding for several proteins of the TLR signaling axis, including TLR adaptor molecules and genes associated with MAPK pathway, NFκB activation and antiviral immune response. In particular, we observed major alterations in the HMGB1-TLR4 signaling axis. Functional analysis also showed that HMGB1 expression is important for the proliferative and tumorigenic potential of cervical cancer cell lines. Taken together, these data indicate that alterations in TLR signaling pathways may play a role in the oncogenic potential of cells expressing HPV oncogenes.

Human Papillomavirus Infection, Infertility, and Assisted Reproductive Outcomes

The human papillomavirus (HPV) is a sexually transmitted infection common among men and women across all geographic and socioeconomic subgroups worldwide. Recent evidence suggests that HPV infection may affect fertility and alter the efficacy of assisted reproductive technologies. In men, HPV infection can affect sperm parameters, specifically motility. HPV-infected sperm can transmit viral DNA to oocytes, which may be expressed in the developing blastocyst. HPV can increase trophoblastic apoptosis and reduce the endometrial implantation of trophoblastic cells, thus increasing the theoretical risk of miscarriage. Vertical transmission of HPV during pregnancy may be involved in the pathophysiology of preterm rupture of membranes and spontaneous preterm birth. In patients undergoing intrauterine insemination for idiopathic infertility, HPV infection confers a lower pregnancy rate. In contrast, the evidence regarding any detrimental impact of HPV infection on IVF outcomes is inconclusive. It has been suggested that vaccination could potentially counter HPV-related sperm impairment, trophoblastic apoptosis, and spontaneous miscarriages; however, these conclusions are based on in vitro studies rather than large-scale epidemiological studies. Improvement in the understanding of HPV sperm infection mechanisms and HPV transmission into the oocyte and developing blastocyst may help explain idiopathic causes of infertility and miscarriage.

Role of IL-10 and TGF-β1 in local immunosuppression in HPV-associated cervical neoplasia

Cervical cancer is a worldwide disease that constitutes a significant public health problem, especially in developing countries, not only due to its high incidence but also because the most affected population comprises women who belong to marginalized socio-economic classes. Clinical and molecular research has identified immunological impairment in squamous intraepithelial cervical lesions and cervical cancer patients. Human Papillomavirus (HPV) has several mechanisms for avoiding the immune system: it down-regulates the expression of interferon and upregulates interleukin (IL)-10 and transforming growth factor (TGF)-β1 to produce a local immunosuppressive environment, which, along with altered tumor surface antigens, forms an immunosuppressive network that inhibits the antitumor immune response. In this review we analyzed the available data on several deregulated cellular immune functions in patients with NIC I, NIC II and NIC III and cervical cancer. The effects of immunosuppressive cytokines on innate immune response, T-cell activation and cellular factors that promote tumor cell proliferation in cervical cancer patients are summarized. We discuss the functional consequences of HPV E2, E6, and E7 protein interactions with IL-10 and TGF-β1 promoters in the induction of these cytokines and postulate its effect on the cellular immune response in squamous intraepithelial cervical lesions and cervical cancer patients. This review provides a comprehensive picture of the immunological functions of IL-10 and TGF-β1 in response to HPV in humans.

Asymptomatic oral human papillomavirus (HPV) infection in women with a histopathologic diagnosis of genital HPV

The oral route of human papillomavirus (HPV) transmission is not fully understood. It has been suggested that genital infection can act as a reservoir for oral HPV infection. We investigated the presence of oral HPV DNA and anti-HPV IgA in the buccal cavity of patients with a histopathologic diagnosis of cervical HPV infection. One hundred women underwent oral clinical examinations to detect HPV-DNA by polymerase chain reaction and salivary anti-HPV IgA by indirect immunofluorescence. Information on the personal habits of all the women was collected in personal interviews. Our results showed that 99% of the patients had no clinical manifestations of oral HPV. However, HPV DNA was detected in 81% of oral mucosa samples, and anti-HPV IgA was detected in the saliva of 44% of the patients. Consumption of alcoholic beverages was significantly associated with detection of oral HPV DNA and salivary anti-HPV IgA. Other behavioral risk factors associated with oral HPV and anti-HPV IgA are also discussed. In conclusion, patients with genital HPV infection are at risk for subclinical oral HPV infection. Thus, a molecular assay might be necessary to diagnose such infections.

The immune response to tumors as a tool toward immunotherapy

Until recently cancer medical therapy was limited to chemotherapy that could not differentiate cancer cells from normal cells. More recently with the remarkable mushroom of immunology, newer tools became available, resulting in the novel possibility to attack cancer with the specificity of the immune system. Herein we will review some of the recent achievement of immunotherapy in such aggressive cancers as melanoma, prostatic cancer, colorectal carcinoma, and hematologic malignancies. Immunotherapy of tumors has developed several techniques: immune cell transfer, vaccines, immunobiological molecules such as monoclonal antibodies that improve the immune responses to tumors. This can be achieved by blocking pathways limiting the immune response, such as CTLA-4 or Tregs. Immunotherapy may also use cytokines especially proinflammatory cytokines to enhance the activity of cytotoxic T cells (CTLs) derived from tumor infiltrating lymphocytes (TILs). The role of newly discovered cytokines remains to be investigated. Alternatively, an other mechanism consists in enhancing the expression of TAAs on tumor cells. Finally, monoclonal antibodies may be used to target oncogenes.