Germline genetic regulation of the colorectal tumor immune microenvironment.

OBJECTIVE: To evaluate the contribution of germline genetics to regulating the briskness and diversity of T cell responses in CRC, we conducted a genome-wide association study to examine the associations between germline genetic variation and quantitative measures of T cell landscapes in 2,876 colorectal tumors from participants in the Molecular Epidemiology of Colorectal Cancer Study (MECC). METHODS: Germline DNA samples were genotyped and imputed using genome-wide arrays. Tumor DNA samples were extracted from paraffin blocks, and T cell receptor clonality and abundance were quantified by immunoSEQ (Adaptive Biotechnologies, Seattle, WA). Tumor infiltrating lymphocytes per high powered field (TILs/hpf) were scored by a gastrointestinal pathologist. Regression models were used to evaluate the associations between each variant and the three T-cell features, adjusting for sex, age, genotyping platform, and global ancestry. Three independent datasets were used for replication. RESULTS: We identified a SNP (rs4918567) near RBM20 associated with clonality at a genome-wide significant threshold of 5 × 10- 8, with a consistent direction of association in both discovery and replication datasets. Expression quantitative trait (eQTL) analyses and in silico functional annotation for these loci provided insights into potential functional roles, including a statistically significant eQTL between the T allele at rs4918567 and higher expression of ADRA2A (P = 0.012) in healthy colon mucosa. CONCLUSIONS: Our study suggests that germline genetic variation is associated with the quantity and diversity of adaptive immune responses in CRC. Further studies are warranted to replicate these findings in additional samples and to investigate functional genomic mechanisms.

Heterozygote advantage at HLA class I and II loci and reduced risk of colorectal cancer.

Objective: Reduced diversity at Human Leukocyte Antigen (HLA) loci may adversely affect the host's ability to recognize tumor neoantigens and subsequently increase disease burden. We hypothesized that increased heterozygosity at HLA loci is associated with a reduced risk of developing colorectal cancer (CRC). Methods: We imputed HLA class I and II four-digit alleles using genotype data from a population-based study of 5,406 cases and 4,635 controls from the Molecular Epidemiology of Colorectal Cancer Study (MECC). Heterozygosity at each HLA locus and the number of heterozygous genotypes at HLA class -I (A, B, and C) and HLA class -II loci (DQB1, DRB1, and DPB1) were quantified. Logistic regression analysis was used to estimate the risk of CRC associated with HLA heterozygosity. Individuals with homozygous genotypes for all loci served as the reference category, and the analyses were adjusted for sex, age, genotyping platform, and ancestry. Further, we investigated associations between HLA diversity and tumor-associated T cell repertoire features, as measured by tumor infiltrating lymphocytes (TILs; N=2,839) and immunosequencing (N=2,357). Results: Individuals with all heterozygous genotypes at all three class I genes had a reduced odds of CRC (OR: 0.74; 95% CI: 0.56-0.97, p= 0.031). A similar association was observed for class II loci, with an OR of 0.75 (95% CI: 0.60-0.95, p= 0.016). For class-I and class-II combined, individuals with all heterozygous genotypes had significantly lower odds of developing CRC (OR: 0.66, 95% CI: 0.49-0.87, p= 0.004) than those with 0 or one heterozygous genotype. HLA class I and/or II diversity was associated with higher T cell receptor (TCR) abundance and lower TCR clonality, but results were not statistically significant. Conclusion: Our findings support a heterozygote advantage for the HLA class-I and -II loci, indicating an important role for HLA genetic variability in the etiology of CRC.

Diversity of Anal HPV and Non-HPV Sexually Transmitted Infections and Concordance with Genital Infections in HIV-Infected and HIV-Uninfected Women in the Tapajós Region, Amazon, Brazil.

The aim of this study was to classify the diversity of anal HPV and non-HPV sexually transmitted infections (STIs) and compare the concordance between anal and genital infections in HIV-infected and uninfected women living in the Tapajós region, Amazon, Brazil. A cross-sectional study was performed with 112 HIV-uninfected and 41 HIV-infected nonindigenous women. Anal and cervical scrapings were collected and analyzed for HPV, Chlamydia trachomatis (CT), Neisseria gonorrheae (NG), Trichomonas vaginalis (TV), Mycoplasma genitalium (MG), and Human alphaherpesvirus 2 (HSV-2). The Kappa test evaluated the concordance between anal and genital infections. The overall prevalence of anal HPV infection was 31.3% in HIV-uninfected and 97.6% in HIV-infected women. The most frequent anal high-risk HPV (hrHPV) types were HPV18 and HPV16 in HIV-uninfected women and HPV51, HPV59, HPV31, and HPV58 in HIV-infected women. Anal HPV75 Betapapillomavirus was also identified. Anal non-HPV STIs were identified in 13.0% of all participants. The concordance analysis was fair for CT, MG, and HSV-2, almost perfect agreement for NG, moderate for HPV, and variable for the most frequent anal hrHPV types. Thus, a high prevalence of anal HPV infection with moderate and fair concordance between anal and genital HPV and non-HPV STIs was observed in our study.

Examining multilevel influences on parental HPV vaccine hesitancy among multiethnic communities in Los Angeles: a qualitative analysis.

BACKGROUND: Human papillomavirus (HPV) vaccine hesitancy is a growing concern in the United States, yet understudied among racial/ethnic minority parents. We conducted qualitative research to understand parental HPV vaccine hesitancy and inform community-specific, multilevel approaches to improve HPV vaccination among diverse populations in Los Angeles. METHODS: We recruited American Indian/Alaska Native (AI/AN), Hispanic/Latino/a (HL) and Chinese parents of unvaccinated children (9-17 years) from low-HPV vaccine uptake regions in Los Angeles for virtual focus groups (FGs). FGs were conducted in English (2), Mandarin (1), and Spanish (1) between June-August 2021. One English FG was with AI/AN-identifying parents. FGs prompted discussions about vaccine knowledge, sources of information/hesitancy, logistical barriers and interpersonal, healthcare and community interactions regarding HPV vaccination. Guided by the social-ecological model, we identified multilevel emergent themes related to HPV vaccination. RESULTS: Parents (n = 20) in all FGs reported exposure to HPV vaccine information from the internet and other sources, including in-language media (Mandarin) and health care providers (Spanish). All FGs expressed confusion around the vaccine and had encountered HPV vaccine misinformation. FGs experienced challenges navigating relationships with children, providers, and friends/family for HPV vaccine decision-making. At the community-level, historical events contributed to mistrust (e.g., forced community displacement [AI/AN]). At the societal-level, transportation, and work schedules (Spanish, AI/AN) were barriers to vaccination. Medical mistrust contributed to HPV vaccine hesitancy across the analysis levels. CONCLUSION: Our findings highlight the importance of multilevel influences on parental HPV vaccine hesitancy and decision-making and the need for community-specific messaging to combat medical mistrust and other barriers to HPV vaccination among racial/ethnic minority communities.

Understanding medical mistrust and HPV vaccine hesitancy among multiethnic parents in Los Angeles.

Determinants of parental HPV vaccine hesitancy, including medical mistrust and exposure to negative vaccine information, are understudied in racial/ethnic minority communities where vaccine uptake is low. We conducted a cross-sectional survey (March 2021) among parents of adolescents, ages 9-17 years, from an academic enrichment program serving low-income, first-generation, underrepresented minority families in Los Angeles to understand determinants of parental HPV vaccine hesitancy. Parents completed self-administered surveys, including a 9-item HPV vaccine hesitancy scale, in either English, Spanish, or Chinese. Logistic regression was used to identify individual and interpersonal factors associated with parental hesitancy and adolescent HPV vaccination. One-fifth of parents (n = 357) reported high HPV vaccine hesitancy and > 50% reported concerns about safety or side effects. High medical mistrust was associated with high parental HPV vaccine hesitancy (adjusted-OR 1.69, 95% CI: 1.13, 2.37). Community-tailored and multilevel strategies to increase vaccine confidence are needed to improve HPV and other adolescent vaccinations.

Investigation of the Optimal Prime Boost Spacing Regimen for a Cancer Therapeutic Vaccine Targeting Human Papillomavirus.

Therapeutic vaccine studies should be designed to elicit durable, high magnitude, and efficacious T cell responses, all of which can be impacted by the choice of the vaccination schedule. Here, we compare different prime-boost intervals (PBI) in a human papillomavirus (HPV) model using a HPV16E7E6 Venezuelan equine encephalitis virus replicon particle (VRP) vaccination to address the optimal boosting schedule, quality of immune response, and overall in vivo efficacy. Six different vaccine regimens were tested with each group receiving booster vaccinations at different time intervals. Analysis of T-cell responses demonstrated a significant HPV16 E7 specific CD8+ T cell response with at minimum a one-week PBI between antigen re-exposure. Significant E7-specific in vivo cytotoxicity was also observed with longer PBIs. Additionally, longer PBIs led to an enhanced memory recall response to tumor challenge, which correlated with differential expansion of T cell memory subsets. Our findings imply that when using alphavirus vector platforms as a vaccination strategy, a one-week PBI is sufficient to induce high magnitude effector T cells with potent anti-tumor activity. However, longer PBIs lead to enhanced long-term protective anti-tumor immunity. These findings have implications for therapeutic vaccine clinical trials in which shorter intervals of prime-boost regimens may lead to suboptimal durable immune responses.

Integration of immunotherapy into treatment of cervical cancer: Recent data and ongoing trials.

Cervical cancer constitutes a significant health burden for women globally. While most patients with early-stage disease can be cured with radical surgery or chemoradiotherapy, patients with high-risk locally advanced disease or with recurrent/metastatic disease have a poor prognosis with standard treatments. Immunotherapies are a rational treatment for this HPV-driven cancer that commonly expresses programmed cell death ligand-1. Before 2021, pembrolizumab was the only United States Food and Drug Administration-approved immunotherapy in cervical cancer, specifically for the second-line recurrent or metastatic (r/m) setting. In late 2021, the antibody-drug conjugate tisotumab vedotin was approved for second-line r/m cervical cancer and pembrolizumab combined with chemotherapy ± bevacizumab was approved for first-line r/m disease based on results from KEYNOTE-826. Moreover, with at least 2 dozen additional immunotherapy clinical trials in the second-line and first-line r/m setting, as well as in locally advanced disease, the treatment landscape for cervical cancer may eventually encounter a potential paradigm shift. Pivotal trials of immunotherapies for cervical cancer that were recently approved or with the potential for regulatory consideration through 2024 are reviewed. As immunotherapy has the opportunity to establish new standards of care in the treatment of cervical cancers, new biomarkers to identify the ideal patient populations for these therapies may also become important. However, issues with access, affordability, and compliance in low- and middle-income countries are anticipated.

Quantitative MRI cell tracking of immune cell recruitment to tumors and draining lymph nodes in response to anti-PD-1 and a DPX-based immunotherapy.

DPX is a unique T cell activating formulation that generates robust immune responses (both clinically and preclinically) which can be tailored to various cancers via the use of tumor-specific antigens and adjuvants. While DPX-based immunotherapies may act complementary with checkpoint inhibitors, combination therapy is not always easily predictable based on individual therapeutic responses. Optimizing these combinations can be improved by understanding the mechanism of action underlying the individual therapies. Magnetic Resonance Imaging (MRI) allows tracking of cells labeled with superparamagnetic iron oxide (SPIO), which can yield valuable information about the localization of crucial immune cell subsets. In this work, we evaluated the use of a multi-echo, single point MRI pulse sequence, TurboSPI, for tracking and quantifying cytotoxic T lymphocytes (CTLs) and myeloid lineage cells (MLCs). In a subcutaneous cervical cancer model (C3) we compared untreated mice to mice treated with either a single therapy (anti-PD-1 or DPX-R9F) or a combination of both therapies. We were able to detect, using TurboSPI, significant increases in CTL recruitment dynamics in response to combination therapy. We also observed differences in MLC recruitment to therapy-draining (DPX-R9F) lymph nodes in response to treatment with DPX-R9F (alone or in combination with anti-PD-1). We demonstrated that the therapies presented herein induced time-varying changes in cell recruitment. This work establishes that these quantitative molecular MRI techniques can be expanded to study a number of cancer and immunotherapy combinations to improve our understanding of longitudinal immunological changes and mechanisms of action.

Theta-Defensins Inhibit High-Risk Human Papillomavirus Infection Through Charge-Driven Capsid Clustering.

Persistent infection with high-risk human papillomavirus (hrHPV) genotypes results in a large number of anogenital and head and neck cancers worldwide. Although prophylactic vaccination coverage has improved, there remains a need to develop methods that inhibit viral transmission toward preventing the spread of HPV-driven disease. Defensins are a class of innate immune effector peptides that function to protect hosts from infection by pathogens such as viruses and bacteria. Previous work utilizing α and ß defensins from humans has demonstrated that the α-defensin HD5 is effective at inhibiting the most common high-risk genotype, HPV16. A third class of defensin that has yet to be explored are θ-defensins: small, 18-amino acid cyclic peptides found in old-world monkeys whose unique structure makes them both highly cationic and resistant to degradation. Here we show that the prototype θ-defensin, rhesus theta defensin 1, inhibits hrHPV infection through a mechanism involving capsid clustering that inhibits virions from binding to cell surface receptor complexes.

Immune Activation in Patients with Locally Advanced Cervical Cancer Treated with Ipilimumab Following Definitive Chemoradiation (GOG-9929).

PURPOSE: A phase I clinical trial (GOG-9929) examined the safety and efficacy of adjuvant immune-modulation therapy with the checkpoint inhibitor ipilimumab [anti-CTL antigen-4 (anti-CTLA-4)] following chemoradiation therapy (CRT) for newly diagnosed node-positive human papillomavirus (HPV)-related cervical cancer. To better understand the mechanism of action and to identify predictive biomarkers, immunologic and viral correlates were assessed before, during, and after treatment. PATIENTS AND METHODS: Twenty-one patients who received CRT and ≥2 doses of ipilimumab and 5 patients who received CRT only were evaluable for translational endpoints. Circulating T-cell subsets were evaluated by multiparameter flow cytometry. Cytokines were evaluated by multiplex ELISA. HPV-specific T cells were evaluated in a subset of patients by IFNγ ELISpot. RESULTS: Expression of the activation markers ICOS and PD-1 significantly increased on T-cell subsets following CRT and were sustained or increased following ipilimumab treatment. Combined CRT/ipilimumab treatment resulted in a significant expansion of both central and effector memory T-cell populations. Genotype-specific E6/E7-specific T-cell responses increased post-CRT in 1 of 8 HPV16+ patients and in 2 of 3 HPV18+ patients. Elevation in levels of tumor-promoting circulating cytokines (TNFα, IL6, IL8) post-CRT was significantly associated with worse progression-free survival. CONCLUSIONS: Our data indicate that CRT alone and combined with ipilimumab immunotherapy show immune-modulating activity in women with locally advanced cervical cancer and may be a promising therapeutic option for the enhancement of antitumor immune cell function after primary CRT for this population at high risk for recurrence and metastasis. Several key immune biomarkers were identified that were associated with clinical response.

TNFSF14: LIGHTing the Way for Effective Cancer Immunotherapy.

Tumor necrosis factor superfamily member 14 (LIGHT) has been in pre-clinical development for over a decade and shows promise as a modality of enhancing treatment approaches in the field of cancer immunotherapy. To date, LIGHT has been used to combat cancer in multiple tumor models where it can be combined with other immunotherapy modalities to clear established solid tumors as well as treat metastatic events. When LIGHT molecules are delivered to or expressed within tumors they cause significant changes in the tumor microenvironment that are primarily driven through vascular normalization and generation of tertiary lymphoid structures. These changes can synergize with methods that induce or support anti-tumor immune responses, such as checkpoint inhibitors and/or tumor vaccines, to greatly improve immunotherapeutic strategies against cancer. While investigators have utilized multiple vectors to LIGHT-up tumor tissues, there are still improvements needed and components to be found within a human tumor microenvironment that may impede translational efforts. This review addresses the current state of this field.

The Essential Role of anxA2 in Langerhans Cell Birbeck Granules Formation.

Langerhans cells (LC) are the resident antigen presenting cells of the mucosal epithelium and play an essential role in initiating immune responses. LC are the only cells in the body to contain Birbeck granules (BG), which are unique cytoplasmic organelles comprised of c-type lectin langerin. Studies of BG have historically focused on morphological characterizations, but BG have also been implicated in viral antigen processing which suggests that they can serve a function in antiviral immunity. This study focused on investigating proteins that could be involved in BG formation to further characterize their structure using transmission electron microscopy (TEM). Here, we report a critical role for the protein annexin A2 (anxA2) in the proper formation of BG structures. When anxA2 expression is downregulated, langerin expression decreases, cytoplasmic BG are nearly ablated, and the presence of malformed BG-like structures increases. Furthermore, in the absence of anxA2, we found langerin was no longer localized to BG or BG-like structures. Taken together, these results indicate an essential role for anxA2 in facilitating the proper formation of BG.

Vaccination against Nonmutated Neoantigens Induced in Recurrent and Future Tumors.

Vaccination of patients against neoantigens expressed in concurrent tumors, recurrent tumors, or tumors developing in individuals at risk of cancer is posing major challenges in terms of which antigens to target and is limited to patients expressing neoantigens in their tumors. Here, we describe a vaccination strategy against antigens that were induced in tumor cells by downregulation of the peptide transporter associated with antigen processing (TAP). Vaccination against TAP downregulation-induced antigens was more effective than vaccination against mutation-derived neoantigens, was devoid of measurable toxicity, and inhibited the growth of concurrent and future tumors in models of recurrence and premalignant disease. Human CD8+ T cells stimulated with TAPlow dendritic cells elicited a polyclonal T-cell response that recognized tumor cells with experimentally reduced TAP expression. Vaccination against TAP downregulation-induced antigens overcomes the main limitations of vaccinating against mostly unique tumor-resident neoantigens and could represent a simpler vaccination strategy that will be applicable to most patients with cancer.

Therapeutic efficacy of a human papillomavirus type 16 E7 bacterial exotoxin fusion protein adjuvanted with CpG or GPI-0100 in a preclinical mouse model for HPV-associated disease.

Persistent human papillomavirus (HPV) infection is causally linked to the development of several human cancers, including cervical, vulvar, vaginal, anal, penile, and oropharyngeal cancers. To address the need for a therapeutic vaccine against HPV-associated diseases, here we test and compare the immunogenicity and therapeutic efficacy of a bacterial exotoxin fusion protein covalently linked to the HPV16 E7 oncoprotein adjuvanted with CpG or GPI-0100 in the C3.43 preclinical HPV16-transformed tumor model. We show that TVGV-1 protein vaccine adjuvanted with either CpG or GPI-0100 adjuvant induces a high frequency of E7-specific CD8+ T cells, and both adjuvants are able to assist the immune response in inducing polyfunctional cytokine-secreting lytic T cells that show therapeutic efficacy against well-established C3.43 tumors. CpG-adjuvanted TVGV-1 resulted in higher frequencies of IFNγ secreting and degranulating E7-specific T cells compared to GPI-0100-adjuvanted TVGV-1, resulting in marginally increased in vivo efficacy. Despite minor differences in immune response outcomes, we consider both CpG ODN and GPI-0100 to be promising vaccine adjuvants to increase the immunogenicity and therapeutic efficacy of the TVGV-1 protein for HPV16-driven cancers.

Annexin A2 in Virus Infection.

Viral life cycles consist of three main phases: (1) attachment and entry, (2) genome replication and expression, and (3) assembly, maturation, and egress. Each of these steps is intrinsically reliant on host cell factors and processes including cellular receptors, genetic replication machinery, endocytosis and exocytosis, and protein expression. Annexin A2 (AnxA2) is a membrane-associated protein with a wide range of intracellular functions and a recurrent host factor in a variety of viral infections. Spatially, AnxA2 is found in the nucleus and cytoplasm, vesicle-bound, and on the inner and outer leaflet of the plasma membrane. Structurally, AnxA2 exists as a monomer or in complex with S100A10 to form the AnxA2/S100A10 heterotetramer (A2t). Both AnxA2 and A2t have been implicated in a vast array of cellular functions such as endocytosis, exocytosis, membrane domain organization, and translational regulation through RNA binding. Accordingly, many discoveries have been made involving AnxA2 in viral pathogenesis, however, the reported work addressing AnxA2 in virology is highly compartmentalized. Therefore, the purpose of this mini review is to provide information regarding the role of AnxA2 in the lifecycle of multiple epithelial cell-targeting viruses to highlight recurrent themes, identify discrepancies, and reveal potential avenues for future research.

Validity and prognostic significance of sperm protein 17 as a tumor biomarker for epithelial ovarian cancer: a retrospective study.

BACKGROUND: Prior small studies have shown increased expression of sperm protein 17 (Sp17) in epithelial ovarian cancer (EOC) tissue and suggest Sp17 as a potential biomarker for EOC. However, how Sp17 expression varies with histology, grade, and stage of EOC and its expression in other ovarian neoplasms has not been defined. It is unknown whether patients with EOC have elevated serum Sp17 levels or if Sp17 expression is associated with survival outcomes. METHODS: The study included 982 patients with benign, borderline, and malignant ovarian neoplasms and normal ovary. There were 878 patients with tissue only, 39 with serum only, and 65 with matching serum and tissue. Immunohistochemical (IHC) staining with anti-Sp17 antibody was performed on tissue specimens and the intensity scored as weak, moderate, or strong. A sandwich enzyme-linked immunosorbent assay (ELISA) was performed to measure Sp17 sera concentrations. RESULTS: Sp17 expression was most commonly seen in serous cystadenomas (83%) and serous borderline tumors (100%). Of the 773 EOC specimens, 223 (30%) expressed Sp17. Grade and histology were significantly associated with Sp17 expression among EOC specimens (p < 0.001) on both univariate and multivariable analysis, with grade 1 serous adenocarcinomas showing the highest expression (51%). Sp17 expression was limited in other benign and non-epithelial malignant neoplasms. Neither Sp17 tissue expression nor serum concentration correlated with survival outcomes. Serum concentrations were higher in patients with Sp17 tissue expression, and the highest concentrations were noted among patients with serous and clear cell adenocarcinomas. CONCLUSIONS: Sp17 is highly expressed in benign, borderline, and low grade malignant serous ovarian neoplasms and can be quantified in serum. Sp17 expression may have diagnostic significance in this subset of patients.

Cervico-vaginal self-collection in HIV-infected and uninfected women from Tapajós region, Amazon, Brazil: High acceptability, hrHPV diversity and risk factors.

OBJECTIVE: We evaluated acceptability of cervico-vaginal self-collection (CVSC) and prevalence of human papillomavirus (HPV) in Human immunodeficiency virus (HIV)-infected and HIV-uninfected women living in the Tapajós region, Amazon, Brazil. METHODS: Cross-sectional study recruited 153 non-indigenous women (HIV-uninfected, n = 112 and HIV-infected, n = 41) who voluntarily sought assistance in health services. Peripheral blood for HIV screening and cervical scraping (CS) for HPV detection were collected. Women who accepted to perform CVSC received instructions and individual collection kits. Risk factors for high-risk HPV genotypes (hrHPV) were identified by uni- and multivariate analyses. RESULTS: The overall acceptability of CVSC was 87%. Only HIV-infected women had cytological abnormalities (12.2%). Prevalence of any HPV and hrHPV infection was 42.9% and 47.9% for HIV-uninfected and 97.6% and 77.5% for HIV-infected women, respectively. There was significant agreement in the detection of HPV (88%, 0.76, 95% confidence interval [CI], 0.65-0.87) and hrHPV (79.7%, 0.56, 95% CI, 0.41-0.71) between self-collected and clinician-collected samples. The most prevalent hrHPV types were HPV16 and HPV18 in HIV-uninfected and HPV16, HPV51 and HPV59 in HIV-infected women. HIV-infected women with hrHPV infection had multiple hrHPV infections (p = 0.005) and lower CD4 count (p = 0.018). Risk factors for hrHPV infection included being HIV-infected and having five or more sexual partners. CONCLUSIONS: CVSC had high acceptability and high prevalence of hrHPV types in women living in the Tapajós region, Amazon, Brazil.

Heterotetrameric annexin A2/S100A10 (A2t) is essential for oncogenic human papillomavirus trafficking and capsid disassembly, and protects virions from lysosomal degradation.

Human papillomavirus (HPV) entry into epithelial cells is independent of canonical endocytic pathways. Upon interaction with host cells, HPV establishes infection by traversing through an endocytic pathway that is clathrin- and caveolin-independent, but dependent on the annexin A2/S100A10 heterotetramer (A2t). We examined the contribution of monomeric annexin A2 (AnxA2) vs. A2t in HPV infection and endocytosis, and further characterized the role of these molecules in protein trafficking. We specifically show that cell surface A2t is not required for HPV attachment, and in the absence of A2t virion internalization remains clathrin-independent. Without A2t, viral progression from early endosomes to multivesicular endosomes is significantly inhibited, capsid uncoating is dramatically reduced, and lysosomal degradation of HPV is accelerated. Furthermore, we present evidence that AnxA2 forms a complex with CD63, a known mediator of HPV trafficking. Overall, the observed reduction in infection is less significant in the absence of S100A10 alone compared to full A2t, supporting an independent role for monomeric AnxA2. More broadly, we show that successful infection by multiple oncogenic HPV types is dependent on A2t. These findings suggest that A2t is a central mediator of high-risk HPV intracellular trafficking post-entry and pre-viral uncoating.

Nanobody-Antigen Conjugates Elicit HPV-Specific Antitumor Immune Responses.

High-risk human papillomavirus-associated cancers express viral oncoproteins (e.g., E6 and E7) that induce and maintain the malignant phenotype. The viral origin of these proteins makes them attractive targets for development of a therapeutic vaccine. Camelid-derived single-domain antibody fragments (nanobodies or VHHs) that recognize cell surface proteins on antigen-presenting cells (APC) can serve as targeted delivery vehicles for antigens attached to them. Such VHHs were shown to induce CD4+ and CD8+ T-cell responses against model antigens conjugated to them via sortase, but antitumor responses had not yet been investigated. Here, we tested the ability of an anti-CD11b VHH (VHHCD11b) to target APCs and serve as the basis for a therapeutic vaccine to induce CD8+ T-cell responses against HPV+ tumors. Mice immunized with VHHCD11b conjugated to an H-2Db-restricted immunodominant E7 epitope (E749-57) had more E7-specific CD8+ T cells compared with those immunized with E749-57 peptide alone. These CD8+ T cells acted prophylactically and conferred protection against a subsequent challenge with HPV E7-expressing tumor cells. In a therapeutic setting, VHHCD11b-E749-57 vaccination resulted in greater numbers of CD8+ tumor-infiltrating lymphocytes compared with mice receiving E749-57 peptide alone in HPV+ tumor-bearing mice, as measured by in vivo noninvasive VHH-based immune-positron emission tomography (immunoPET), which correlated with tumor regression and survival outcome. Together, these results demonstrate that VHHs can serve as a therapeutic cancer vaccine platform for HPV-induced cancers. Cancer Immunol Res; 6(7); 870-80. ©2018 AACR.