Engineering Dimeric EGFR-directed IgA Antibodies Reveals a Central Role of CD147 during Neutrophil-mediated Tumor Cell Killing of Head and Neck Squamous Cancer Cells.

Human IgA Abs engage neutrophils for cancer immunotherapy more effectively than IgG Abs. Previous studies demonstrated that engineering approaches improved biochemical and functional properties. In this study, we report a novel, to our knowledge, IgA2 Ab against the epidermal growth factor receptor generated by protein engineering and polymerization. The resulting molecule demonstrated a covalent linkage of L and H chains and an effective polymerization by the joining chain. The engineered dimer outperformed its monomeric variant in functional experiments on Fab-mediated modes of action and binding to the Fc receptor. The capacity to engage neutrophils for Ab-dependent cell-mediated cytotoxicity (ADCC) of adherent growing target cancer cells was cell line dependent. Although the engineered dimer displayed a long-term efficacy against the vulva carcinoma cell line A431, there was a notable in-efficacy against human papillomavirus (HPV)- head and neck squamous cell carcinoma (HNSCC) cell lines. However, the highly engineered IgA Abs triggered a neutrophil-mediated cytotoxicity against HPV+ HNSCC cell lines. Short-term ADCC efficacy correlated with the target cells' epidermal growth factor receptor expression and the ability of cancer cell-conditioned media to enhance the CD147 surface level on neutrophils. Notably, the HPV+ HNSCC cell lines demonstrated a significant increment in releasing soluble CD147 and a reduced induction of membranous CD147 on neutrophils compared with HPV- cells. Although membranous CD147 on neutrophils may impair proper IgA-Fc receptor binding, soluble CD147 enhanced the IgA-neutrophil-mediated ADCC in a dose-dependent manner. Thus, engineering IgA Abs and impedance-based ADCC assays provided valuable information regarding the target-effector cell interaction and identified CD147 as a putative critical parameter for neutrophil-mediated cytotoxicity.

IgG seroprevalence of COVID-19 among people living with HIV or at high risk of HIV in south-west Germany: A seroprevalence study.

OBJECTIVES: Seroprevalence studies of SARS-CoV-2 have shown that there is a high number of undiagnosed missing cases. Seroprevalence of SARS-CoV-2 in people living with HIV (PLWH) is lacking. Therefore, we conducted a prospective cross-sectional study to estimate the seroprevalence of SARS-CoV-2 among PLWH without known diagnosis of COVID-19 in the south-west of Germany. METHODS: Serological testing for SARS-CoV-2 immunoglobulin G (IgG) antibodies based on two assays was performed in PLWH who visited the outpatient HIV centre of two hospitals from April to June 2020. Additionally, patients had to answer questionnaires about possible COVID-19-related symptoms and predefined risk factors. Moreover, we tested 50 non-HIV-infected patients receiving post- or pre-exposure (PEP/PrEP) HIV prophylaxis. RESULTS: In all, 594 (488 male, 106 female) PLWH (median age 51 years) and 50 PEP/PrEP-users were included in the study. The estimated seroprevalence of the PLWH cohort was 1.85% (11/594), with 11 positive tested cases in the cohort. Among all patients, only five had COVID-19-related symptoms. One PCR-positive patient did not show any antibody response in repeatedly carried out tests. None of the patients was hospitalized due to COVID-19. Three PrEP users were tested positive. Three patients had been previously diagnosed with SARS-COV-2 infection before inclusion. The used questionnaire did not help to detect SARS-CoV-2 positive patients. CONCLUSIONS: Despite the limitation of being only a snapshot in time because of the ongoing pandemic, to our knowledge this is the largest study so far on seroprevalence of SARS-CoV-2 in PLWH in Germany. Our study suggests that the seroprevalence of SARS-CoV-2 in PLWH is comparable to those previously reported for parts of the general German population and that the questionnaire used here might not be the best tool to predict COVID-19 diagnosis.

A Complement-Optimized EGFR Antibody Improves Cytotoxic Functions of Polymorphonuclear Cells against Tumor Cells.

Complement-dependent cytotoxicity (CDC) has been suggested to be an important mechanism of action of tumor-targeting Abs. However, single unmodified epidermal growth factor receptor (EGFR)-targeting IgG1 Abs fail to trigger efficient CDC. For the current study, we generated a CDC-optimized variant of the EGFR Ab matuzumab (H425 wt) by introducing amino acid substitutions K326A/E333A (H425 mt). This Ab was then used to elucidate the impact of complement activation on the capacity of effector cells such as mononuclear cells (MNC) and polymorphonuclear cells (PMN) to exert Ab-dependent cell-mediated cytotoxicity (ADCC). H425 mt, but not H425 wt, significantly induced complement deposition, release of anaphylatoxins, and CDC against distinct tumor cell lines, whereas no differences in ADCC by MNC or PMN were detected. Notably, stronger cytotoxicity was induced by H425 mt than by H425 wt in whole blood assays and in experiments in which MNC or PMN were combined with serum. Although MNC-ADCC was not affected by C5 cleavage, the cytotoxic activity of PMN in the presence of serum strongly depended on C5 cleavage, pointing to a direct interaction between complement and PMN. Strong cell surface expression of C5a receptors was detected on PMN, whereas NK cells completely lacked expression. Stimulation of PMN with C5a led to upregulation of activated complement receptor 3, resulting in enhanced complement receptor 3-dependent PMN-ADCC against tumor cells. In conclusion, complement-optimized EGFR Abs may constitute a promising strategy to improve tumor cell killing by enhancing the interaction between humoral and cellular effector functions in Ab-based tumor therapy.

Epidermal growth factor receptor targeting IgG3 triggers complement-mediated lysis of decay-accelerating factor expressing tumor cells through the alternative pathway amplification loop.

Binding of C1q to target-bound IgG initiates complement-mediated lysis (CML) of pathogens, as well as of malignant or apoptotic cells, and thus constitutes an integral part of the innate immune system. Despite its prominent molecular flexibility and higher C1q binding affinity compared with human IgG1, IgG3 does not consistently promote superior CML. Hence the aim of this study was to investigate underlying molecular mechanisms of IgG1- and IgG3-driven complement activation using isotype variants of the therapeutic epidermal growth factor receptor (EGFR) Ab cetuximab. Both IgG1 and IgG3 Abs demonstrated similar EGFR binding and similar efficiency in Fab-mediated effector mechanisms. Whereas anti-EGFR-IgG1 did not promote CML of investigated target cells, anti-EGFR-IgG3 triggered significant CML of some, but not all tested cell lines. CML triggered by anti-EGFR-IgG3 negatively correlated with expression levels of the membrane-bound complement regulatory proteins CD55 and CD59, but not CD46. Notably, anti-EGFR-IgG3 promoted strong C1q and C3b, but relatively low C4b and C5b-9 deposition on analyzed cell lines. Furthermore, anti-EGFR-IgG3 triggered C4a release on all cells but failed to induce C3a and C5a release on CD55/CD59 highly expressing cells. RNA interference-induced knockdown or overexpression of membrane-bound complement regulatory proteins revealed CD55 expression to be a pivotal determinant of anti-EGFR-IgG3-triggered CML and to force a switch from classical complement pathway activation to C1q-dependent alternative pathway amplification. Together, these data suggest human anti-EGFR-IgG3, although highly reactive with C1q, to weakly promote assembly of the classical C3 convertase that is further suppressed in the presence of CD55, forcing human IgG3 to act mainly through the alternative pathway.

Impact of epidermal growth factor receptor (EGFR) cell surface expression levels on effector mechanisms of EGFR antibodies.

The epidermal growth factor receptor (EGFR) is a widely expressed Ag that is successfully targeted in tumor patients by mAbs or tyrosine kinase inhibitors. A clinical study in non-small cell lung cancer patients demonstrated a positive correlation between EGFR expression levels and the therapeutic efficacy of the EGFR mAb cetuximab. However, the impact of EGFR expression on the different mechanisms of action (MoAs) triggered by the EGFR mAb has not been defined. In this study, BHK-21 cells were stably transfected to express different EGFR levels, which were quantified by immunofluorescence and immunohistochemistry and compared with EGFR levels of clinical non-small cell lung cancer samples. These cells were used to systematically investigate the impact of target Ag expression levels on Fab- or Fc-mediated MoAs of EGFR mAb. A negative correlation between EGFR levels and potency of Fab-mediated MoA was observed. Interestingly, Ab-dependent cell-mediated cytotoxicity (ADCC) by NK cells, monocytes, or polymorphonuclear cells as well as complement-dependent cytotoxicity positively correlated with the number of EGFR molecules. In comparison with ADCC by mononuclear cells, polymorphonuclear cell-mediated ADCC and complement-dependent cytotoxicity required higher EGFR expression levels and higher mAb concentrations to trigger significant tumor cell killing. This correlation between EGFR expression levels and Fc-mediated MoA was confirmed in an independent panel of human tumor cell lines carrying diverse genetic alterations. Furthermore, RNA interference-induced knockdown experiments reinforced the impact of EGFR expression on tumor cell killing by EGFR mAb. In conclusion, these results suggest that EGFR expression levels may determine distinct patterns of MoAs that contribute to the therapeutic efficacy of EGFR mAb.

The cutaneous beta human papillomavirus type 8 E6 protein induces CCL2 through the CEBPα/miR-203/p63 pathway to support an inflammatory microenvironment in epidermodysplasia verruciformis skin lesions.

Human papillomavirus type 8 (HPV8), a cutaneous genus beta HPV type, has co-carcinogenic potential at sun-exposed sites in patients suffering from the inherited skin disease epidermodysplasia verruciformis (EV). We had previously shown that Langerhans cells responsible for epithelial immunosurveillance were strongly reduced at infected sites and that the HPV8 E7 protein interferes with the CCAAT/enhancer-binding protein (C/EBP)ß to suppress the Langerhans cell chemokine CCL20. At the same time, however, we observed that EV lesions are heavily infiltrated with inflammatory immune cells, which is similar to the situation in HPV8 E6 transgenic mice. To identify critical inflammatory factors, we used a broad multiplex approach and found that the monocyte attracting chemokine CCL2 was significantly and strongly induced by HPV8 E6 but not E7-expressing HaCaT cells, which were used as a model for UV-damaged skin keratinocytes. Conditioned media from HPV8 E6-expressing keratinocytes enhanced CCL2-receptor (CCR2)-dependent monocyte recruitment in vitro, and macrophages predominated in the stroma but were also detected in the epidermal compartment of EV lesions in vivo. CCL2 induction by HPV8 E6 was even stronger than stimulation with the proinflammatory cytokine TNF-α, and both HPV8 E6 and TNF-α resulted in substantial suppression of the transcription factor C/EBPα. Using RNAi-mediated knockdown and overexpression approaches, we demonstrated a mechanistic role of the recently identified C/EBPα/miR-203/p63 pathway for HPV8 E6-mediated CCL2 induction at protein and transcriptional levels. Epithelial co-expression of p63 and CCL2 was confirmed in HPV8 E6-expressing organotypic air-liquid interface cultures and in lesional EV epidermis in vivo. In summary, our data demonstrate that HPV8 oncoproteins actively deregulate epidermal immune homeostasis through modulation of C/EBP factor-dependent pathways. While HPV8 E7 suppresses immunosurveillance required for viral persistence, the present study provides evidence that E6 involves the stemness-promoting factor p63 to support an inflammatory microenvironment that may fuel carcinogenesis in EV lesions.

Characterization of a mutated IgA2 antibody of the m(1) allotype against the epidermal growth factor receptor for the recruitment of monocytes and macrophages.

IgA antibodies constitute an important part of the mucosal immune system, but their immunotherapeutic potential remains rather unexplored, in part due to biotechnological issues. For example, the IgA2m(1) allotype carries an unusual heavy and light chain pairing, which may confer production and stability concerns. Here, we report the generation and the biochemical and functional characterization of a P221R-mutated IgA2m(1) antibody against the epidermal growth factor receptor (EGFR). Compared with wild type, the mutated antibody demonstrated heavy chains covalently linked to light chains in monomeric as well as in joining (J)-chain containing dimeric IgA. Functional studies with wild type and mutated IgA2m(1) revealed similar binding to EGFR and direct effector functions such as EGFR down-modulation and growth inhibition. Furthermore, both IgA molecules triggered similar levels of indirect tumor cell killing such as antibody-dependent cell-mediated cytotoxicity (ADCC) by isolated monocytes, activated polymorphonuclear cells, and human whole blood. Interestingly, the dimeric IgA antibodies demonstrated higher efficiency in direct as well as in indirect effector mechanisms compared with their respective monomeric forms. Both wild type and mutated antibody triggered effective FcαRI-mediated tumor cell killing by macrophages already at low effector to target cell ratios. Interestingly, also polarized macrophages mediated significant IgA2-mediated ADCC. M2 macrophages, which have been described as promoting tumor growth and progression, may convert to ADCC-mediating effector cells in the presence of EGFR-directed antibodies. In conclusion, these results provide further insight into the immunotherapeutic potential of recombinant IgA antibodies for tumor immunotherapy and suggest macrophages as an additional effector cell population.

Recombinant dimeric IgA antibodies against the epidermal growth factor receptor mediate effective tumor cell killing.

Dimeric IgA Abs contribute significantly to the humoral part of the mucosal immune system. However, their potential as immunotherapeutic agent has hardly been explored. In this article, we describe the production, purification, and functional evaluation of recombinant dimeric IgA against the epidermal growth factor receptor. Human joining chain-containing IgA was produced by nonadherent Chinese hamster ovarian (CHO)-K1 cells under serum-free conditions. Purification by anti-human κ and anti-His-tag affinity, as well as size exclusion chromatography, resulted in a homogenous preparation of highly pure IgA dimers. Functional studies demonstrated dimeric IgA to be at least as effective as monomeric IgA in triggering Ab-dependent cellular cytotoxicity by isolated monocytes or polymorphonuclear cell and in human whole-blood assays. Importantly, dimeric IgA was more effective in F(ab)-mediated killing mechanisms, such as inhibition of ligand binding, receptor downmodulation, and growth inhibition. Furthermore, only dimeric but not monomeric IgA or IgG was directionally transported by the polymeric Ig receptor through an epithelial cell monolayer. Together, these studies demonstrate that recombinant dimeric IgA Abs recruit a distinct repertoire of effector functions compared with monomeric IgA or IgG1 Abs.

Targeting FcαRI on polymorphonuclear cells induces tumor cell killing through autophagy.

Neutrophils are the most abundant circulating FcR-expressing WBCs with potent cytotoxic ability. Currently, they are recognized as promising effector cells for Ab-mediated immunotherapy of cancer, because their capacity to kill tumor cells is greatly enhanced by tumor Ag-specific mAbs. The FcαRI represents the most potent FcR on neutrophils for induction of Ab-mediated tumor cell killing. However, the mechanisms of cell death that are induced are poorly understood. Because these mechanisms can be used for modulation of anticancer treatment, we investigated the tumor cell death induced by neutrophil-mediated Ab-dependent killing via FcαRI. Human mammary carcinoma cells were efficiently killed when incubated with human neutrophils and tumor-specific FcαRI bispecific or IgA Abs. Interestingly, we observed characteristics of autophagy such as autophagic structures by electron microscopy and LC3B(+) autophagosomes in different human epithelial carcinoma cells, which resulted in tumor cell death. To a lesser extent, necrotic features, such as cellular membrane breakdown and spillage of intracellular content, were found. By contrast, apoptotic features including fragmented nuclei, Annexin V-positivity, and presence of cleaved caspase-3 were not observed. These findings indicate that neutrophils mainly facilitate autophagy to induce tumor cell death rather than the more commonly recognized apoptotic cell death mechanisms induced by NK cells or cytotoxic T cells. This knowledge not only reveals the type of tumor cell death induced in neutrophil-mediated, Ab-dependent cellular cytotoxicity, but importantly opens up additional perspectives for modulation of anticancer therapy in, for example, apoptosis-resistant tumor cells.

[Importance of HPV status and p16 for the prognosis of penile carcinoma]. / Bedeutung von HPV-Status und p16 für die Prognose des Peniskarzinoms.

BACKGROUND: Penile cancer is a rare but often lethal tumour disease, especially in the metastatic stage. Most data on prognostic factors for penile cancer are based on small patient cohorts, and even meta-analyses are mostly limited in terms of patient numbers. There is a lack of sufficient parameters to predict the metastatic risk of these tumours. Furthermore, the role of the HPV status for the prognosis, and, in this regard, of p16INK4a is still unclear. MATERIAL AND METHODS: In this study, 236 patients from an international multicentre cohort were analysed with regard to histological subtypes, HPV and p16 status, and other clinical parameters. The HPV status was only graded as HPV-positive if HPV was detected by PCR and the p16 status defined by immunochemistry was positive. The statistical analysis was carried out using the Kaplan-Meier method as well as the log-rank test and a univariable and multivariable analysis using the Cox regression model. RESULTS: A positive HPV status was not a significant parameter for either metastasis-free (MFS), tumour-specific (CSS) or overall survival (OS). p16-positive tumours showed a significantly better MFS (p=0.026), which was also confirmed in the subgroup analysis of HPV-negative tumours (p=0.037) without differences in CSS or OS. In the usual type, there was also a trend towards an improved MFS, but without statistical significance (p=0.070). p16-positive tumours were associated with a highly significantly better MFS (hazard ratio 0.3; p=0.004) in the multivariable Cox regression, while patients with a pT1b tumour stage or advanced lymph node metastasis showed a significantly worse survival. In the multivariable analysis of HPV-negative tumours, p16 status was also confirmed as an independent predictor of MFS (Hazard ratio 0.2; p=0.007). CONCLUSION: HPV status alone seems to be lacking prognostic relevance. In contrast, p16 status was confirmed as an independent prognostic factor. Thus, the expression of p16INK4a is associated with a significantly better MFS. Especially in HPV-negative tumours, the p16 status should be evaluated with regard to the prognostic value and thus also with a view to the treatment decision.

Evaluation of Prognostic Parameters to Identify Aggressive Penile Carcinomas.

BACKGROUND: Advanced penile carcinoma is characterized by poor prognosis. Most data on prognostic factors are based on small study cohorts, and even meta-analyses are limited in patient numbers. Therefore, there is still a lack of evidence for clinical decisions. In addition, the most recent TNM classification is questionable; in line with previous studies, we found that it has not improved prognosis estimation. METHODS: We evaluated 297 patients from Germany, Russia, and Portugal. Tissue samples from 233 patients were re-analyzed by two experienced pathologists. HPV status, p16, and histopathological parameters were evaluated for all patients. RESULTS: Advanced lymph node metastases (N2, N3) were highly significantly associated with reductions in metastasis-free (MFS), cancer-specific (CS), and overall survival (OS) rates (p = <0.001), while lymphovascular invasion was a significant parameter for reduced CS and OS (p = 0.005; p = 0.007). Concerning the primary tumor stage, a significant difference in MFS was found only between pT1b and pT1a (p = 0.017), whereas CS and OS did not significantly differ between T categories. In patients without lymph node metastasis at the time of primary diagnosis, lymphovascular invasion was a significant prognostic parameter for lower MFS (p = 0.032). Histological subtypes differed in prognosis, with the worst outcome in basaloid carcinomas, but without statistical significance. HPV status was not associated with prognosis, either in the total cohort or in the usual type alone. CONCLUSION: Lymphatic involvement has the highest impact on prognosis in penile cancer, whereas HPV status alone is not suitable as a prognostic parameter. The pT1b stage, which includes grading, as well as lymphovascular and perineural invasion in the T stage, seems questionable; a revision of the TNM classification is therefore required.

Human IgG2 antibodies against epidermal growth factor receptor effectively trigger antibody-dependent cellular cytotoxicity but, in contrast to IgG1, only by cells of myeloid lineage.

Ab-dependent cellular cytotoxicity (ADCC) is usually considered an important mechanism of action for immunotherapy with human IgG1 but not IgG2 Abs. The epidermal growth factor receptor (EGF-R) Ab panitumumab represents the only human IgG2 Ab approved for immunotherapy and inhibition of EGF-R signaling has been described as its principal mechanism of action. In this study, we investigated effector mechanisms of panitumumab compared with zalutumumab, an EGF-R Ab of the human IgG1 isotype. Notably, panitumumab was as effective as zalutumumab in recruiting ADCC by myeloid effector cells (i.e., neutrophils and monocytes) in contrast to NK cell-mediated ADCC, which was only induced by the IgG1 Ab. Neutrophil-mediated tumor cell killing could be stimulated by myeloid growth factors and was triggered via FcgammaRIIa. Panitumumab-mediated ADCC was significantly affected by the functional FcgammaRIIa-R131H polymorphism and was induced more effectively by neutrophils from FcgammaRIIa-131H homozygous donors than from -131R individuals. This polymorphism did not affect neutrophil ADCC induced by the IgG1 Ab zalutumumab. The in vivo activity of both Abs was assessed in two animal models: a high-dose model, in which signaling inhibition is a dominant mechanism of action, and a low-dose model, in which effector cell recruitment plays a prominent role. Zalutumumab was more effective than panitumumab in the high-dose model, reflecting its stronger ability to induce EGF-R downmodulation and growth inhibition. In the low-dose model, zalutumumab and panitumumab similarly prevented tumor growth. Thus, our results identify myeloid cell-mediated ADCC as a potent and additional mechanism of action for EGF-R-directed immunotherapy.

Adaptive humoral immune response and cellular immune status in cancer patients and patients under immunosuppression vaccinated against SARS-CoV-2.

BACKGROUND: Patients with cancer and autoimmune diseases are at higher risk of severe COVID-19. They may not develop protective immune responses following vaccination. We investigated patients' cellular and humoral immune response after two COVID-19 vaccine doses. RESEARCH DESIGN AND METHODS: Subjects were stratified into subgroups according to therapy and grade of immunosuppression at time of vaccination. RESULTS: Antibody titers were compared to healthy controls. 32/122 (26%) did not develop detectable antibody titers. Of these, 22 (66.6%) had active therapy. Patients showed significant lower antibody titers compared to controls (median 790 vs. 3923 AU/mL, p = 0.026). Patients with active therapy had significant lower antibody titers compared to those without (median 302 vs. 3952 U/L P < 0.001). B-cell count was lower in the group without antibody titers (median 29.97 vs. 152.8; p = 0.002). 100% of patients under anti-CD20 therapy had no detectable antibody titer, followed by anti-TNF (66%), BTK inhibitors (50%), ruxolitinib (35.5%), TKI (14.2%), and lenalidomide (12.5%). Anti-CD20 therapy, ruxolitinib, BTK inhibitors, and anti-CD38 therapy presented significant lower antibody titers compared to controls. CONCLUSIONS: Patients undergoing therapy for cancer or autoimmune diseases are at higher risk of insufficient humoral immune response following COVID-19 vaccination. Furthermore, alterations in the B-cell compartment correlate with lower antibody titers.

Human papillomavirus vaccination of girls in the German model region Saarland: Insurance data-based analysis and identification of starting points for improving vaccination rates.

In Germany, the incidence of cervical cancer, a disease caused by human papillomaviruses (HPV), is higher than in neighboring European countries. HPV vaccination has been recommended for girls since 2007. However, it continues to be significantly less well received than other childhood vaccines, so its potential for cancer prevention is not fully realized. To find new starting points for improving vaccination rates, we analyzed pseudonymized routine billing data from statutory health insurers in the PRÄZIS study (prevention of cervical carcinoma and its precursors in women in Saarland) in the federal state Saarland serving as a model region. We show that lowering the HPV vaccination age to 9 years led to more completed HPV vaccinations already in 2015. Since then, HPV vaccination rates and the proportion of 9- to 11-year-old girls among HPV-vaccinated females have steadily increased. However, HPV vaccination rates among 15-year-old girls in Saarland remained well below 50% in 2019. Pediatricians vaccinated the most girls overall, with a particularly high proportion at the recommended vaccination age of 9-14 years, while gynecologists provided more HPV catch-up vaccinations among 15-17-year-old girls, and general practitioners compensated for HPV vaccination in Saarland communities with fewer pediatricians or gynecologists. We also provide evidence for a significant association between attendance at the children´s medical check-ups "U11" or "J1" and HPV vaccination. In particular, participation in HPV vaccination is high on the day of U11. However, obstacles are that U11 is currently not financed by all statutory health insurers and there is a lack of invitation procedures for both U11 and J1, resulting in significantly lower participation rates than for the earlier U8 or U9 screenings, which are conducted exclusively with invitations and reminders. Based on our data, we propose to restructure U11 and J1 screening in Germany, with mandatory funding for U11 and organized invitations for HPV vaccination at U11 or J1 for both boys and girls.

The prominent role of the S100A8/S100A9-CD147 axis in the progression of penile cancer.

Currently, no established biomarkers are recommended for the routine diagnosis of penile carcinoma (PeCa). The rising incidence of this human papillomavirus (HPV)-related cancer entity highlights the need for promising candidates. The Calprotectin subunits S100A8 and S100A9 mark myeloid-derived suppressor cells in other HPV-related entities while their receptor CD147 was discussed to identify patients with PeCa at a higher risk for poor prognoses and treatment failure. We thus examined their expression using immunohistochemistry staining of PeCa specimens from 74 patients on tissue microarrays of the tumor center, the invasion front, and lymph node metastases. Notably, whereas the tumor center was significantly more intensively stained than the invasion front, lymph node metastases were thoroughly positive for both S100 subunits. An HPV-positive status combined with an S100A8+S100A9+ profile was related with an elevated risk for metastases. We observed several PeCa specimens with S100A8+S100A9+-infiltrating immune cells overlapping with CD15 marking neutrophils. The S100A8+S100A9+CD15+ profile was associated with dedifferentiated and metastasizing PeCa, predominantly of HPV-associated subtype. These data suggest a contribution of neutrophil-derived suppressor cells to the progression of HPV-driven penile carcinogenesis. CD147 was elevated, expressed in PeCa specimens, prominently at the tumor center and in HPV-positive PeCa cell lines. CD147+HPV+ PeCa specimens were with the higher-frequency metastasizing cancers. Moreover, an elevated expression of CD147 of HPV-positive PeCa cell lines correlated negatively with the susceptibility to IgA-based neutrophil-mediated tumor cell killing. Finally, stratifying patients regarding their HPV/S100A8/S100A9/CD15/CD147 profile may help identify patients with progressing cancer and tailor immunotherapeutic treatment strategies.

DKK1 inhibits canonical Wnt signaling in human papillomavirus-positive penile cancer cells.

Penile squamous cell cancer (PSCC) is the most frequent penile malignant disease. Infections with human papillomaviruses (HPV) are a major etiologic driver of PSCC. However, the molecular details of the underlying carcinogenesis are understudied because of rare clinical specimens and missing cell lines. Here, we investigated if the expression of high-risk HPV16 oncogenes causes an augmentation of the Wnt pathway using unique HPV-positive penile cancer (PeCa) cell lines in monolayer and organotypic 3D raft cultures as well as tissue micro arrays containing clinical tissue specimens. The HPV oncoproteins enhanced the expression of Leucine-rich repeat-containing G-protein coupled receptor 6 (LGR6) and the HPV-positive PeCa cells expressed a signature of Wnt target and stemness-associated genes. However, the notable lack of nuclear ß-catenin in vitro and in situ raised the question if the enhanced expression of Wnt pathway factors is tantamount to an active Wnt signaling. Subsequent TOP-flash reporter assays revealed Wnt signaling as absent and not inducible by respective Wnt ligands in PeCa cell lines. The HPV-positive PeCa cells and especially HPV-positive PeCa specimens of the tumor core expressed the Wnt antagonist and negative feedback-regulator Dickkopf1 (DKK1). Subsequent neutralization experiments using PeCa cell line-conditioned media demonstrated that DKK1 is capable to impair ligand-induced Wnt signaling. While gene expression analyses suggested an augmented and active canonical Wnt pathway, the respective signaling was inhibited due to the endogenous expression of the antagonist DKK1. Subsequent TMA stainings indicated Dkk1 as linked with HPV-positivity and metastatic disease progression in PeCa suggesting potential as a prognostic marker.

B-cell receptors of EBV-negative Burkitt lymphoma bind modified isoforms of autoantigens.

Burkitt lymphoma (BL) represents the most aggressive B-cell-lymphoma. Beside the hallmark of IG-MYC-translocation, surface B-cell receptor (BCR) is expressed, and mutations in the BCR pathway are frequent. Coincidental infections in endemic BL, and specific extra-nodal sites suggest antigenic triggers. To explore this hypothesis, BCRs of BL cell lines and cases were screened for reactivities against a panel of bacterial lysates, lysates of Plasmodium falciparum, a custom-made virome array and against self-antigens, including post-translationally modified antigens. An atypically modified, SUMOylated isoform of Bystin, that is, SUMO1-BYSL was identified as the antigen of the BCR of cell line CA46. SUMO1-BYSL was exclusively expressed in CA46 cells with K139 as site of the SUMOylation. Secondly, an atypically acetylated isoform of HSP40 was identified as the antigen of the BCR of cell line BL41. K104 and K179 were the sites of immunogenic acetylation, and the acetylated HSP40 isoform was solely present in BL41 cells. Functionally, addition of SUMO1-BYSL and acetylated HSP40 induced BCR pathway activation in CA46 and BL41 cells, respectively. Accordingly, SUMO1-BYSL-ETA' immunotoxin, produced by a two-step intein-based conjugation, led to the specific killing of CA46 cells. Autoantibodies directed against SUMO1-BYSL were found in 3 of 14 (21.4%), and autoantibodies against acetylated HSP40 in 1/14(7.1%) patients with sporadic Burkitt-lymphoma. No reactivities against antigens of the infectious agent spectrum could be observed. These results indicate a pathogenic role of autoreactivity evoked by immunogenic post-translational modifications in a subgroup of sporadic BL including two EBV-negative BL cell lines.

German federal-state-wide seroprevalence study of 1st SARS-CoV-2 pandemic wave shows importance of long-term antibody test performance.

Background: Reliable data on the adult SARS-CoV-2 infection fatality rate in Germany are still scarce. We performed a federal state-wide cross-sectional seroprevalence study named SaarCoPS, that is representative for the adult population including elderly individuals and nursing home residents in the Saarland. Methods: Serum was collected from 2940 adults via stationary or mobile teams during the 1st pandemic wave steady state period. We selected an antibody test system with maximal specificity, also excluding seroreversion effects due to a high longitudinal test performance. For the calculations of infection and fatality rates, we accounted for the delays of seroconversion and death after infection. Results: Using a highly specific total antibody test detecting anti-SARS-CoV-2 responses over more than 180 days, we estimate an adult infection rate of 1.02% (95% CI: [0.64; 1.44]), an underreporting rate of 2.68-fold (95% CI: [1.68; 3.79]) and infection fatality rates of 2.09% (95% CI: (1.48; 3.32]) or 0.36% (95% CI: [0.25; 0.59]) in all adults including elderly individuals, or adults younger than 70 years, respectively. Conclusion: The study highlights the importance of study design and test performance for seroprevalence studies, particularly when seroprevalences are low. Our results provide a valuable baseline for evaluation of future pandemic dynamics and impact of public health measures on virus spread and human health in comparison to neighbouring countries such as Luxembourg or France.