Probes for INS

Bacterial lipoproteins are an often-underappreciated class of microbe-associated molecular patterns with potent immunomodulatory activity. We previously reported that vaccination of BALB/c mice with Mycoplasma pneumoniae (Mp) lipid-associated membrane proteins (LAMPs) resulted in lipoprotein-dependent vaccine enhanced disease after challenge with virulent Mp, though the immune responses underpinning this phenomenon remain poorly understood. Herein, we report that lipoprotein-induced VED in a mouse model is associated with elevated inflammatory cytokines TNF-α, IL-1β, IL-6, IL-17A, and KC in lung lavage fluid and with suppurative pneumonia marked by exuberant neutrophilia in the pulmonary parenchyma. Whole-lung-digest flow cytometry and RNAScope analysis identified multiple cellular sources for IL-17A, and the numbers of IL-17A producing cells were increased in LAMPs-vaccinated/Mp-challenged animals compared to controls. Specific IL-17A or neutrophil depletion reduced disease severity in our VED model-indicating that Mp lipoproteins induce VED in an IL-17A-dependent manner and through exuberant neutrophil recruitment. IL-17A neutralization reduced levels of TNF-α, IL-1β, IL-6, and KC, indicating that IL-17A preceded other inflammatory cytokines. Surprisingly, we found that IL-17A neutralization impaired bacterial clearance, while neutrophil depletion improved it-indicating that, while IL-17A appears to confer both maladaptive and protective responses, neutrophils play an entirely maladaptive role in VED. Given that lipoproteins are found in virtually all bacteria, the potential for lipoprotein-mediated maladaptive inflammatory responses should be taken into consideration when developing vaccines against bacterial pathogens.

Pancreatic ductal adenocarcinoma (PDAC) is a highly metastatic disease. Tumors are poorly immunogenic and immunosuppressive, preventing T cell activation in the tumor microenvironment. Here, we present a microbial-based immunotherapeutic treatment for selective delivery of an immunogenic tetanus toxoid protein (TT856-1313) into PDAC tumor cells by attenuated Listeria monocytogenes. This treatment reactivated preexisting TT-specific memory T cells to kill infected tumor cells in mice. Treatment of KrasG12D,p53R172H, Pdx1-Cre (KPC) mice with Listeria-TT resulted in TT accumulation inside tumor cells, attraction of TT-specific memory CD4 T cells to the tumor microenvironment, and production of perforin and granzyme B in tumors. Low doses of gemcitabine (GEM) increased immune effects of Listeria-TT, turning immunologically cold into hot tumors in mice. In vivo depletion of T cells from Listeria-TT + GEM-treated mice demonstrated a CD4 T cell-mediated reduction in tumor burden. CD4 T cells from TT-vaccinated mice were able to kill TT-expressing Panc-02 tumor cells in vitro. In addition, peritumoral lymph node-like structures were observed in close contact with pancreatic tumors in KPC mice treated with Listeria-TT or Listeria-TT + GEM. These structures displayed CD4 and CD8 T cells producing perforin and granzyme B. Whereas CD4 T cells efficiently infiltrated the KPC tumors, CD8 T cells did not. Listeria-TT + GEM treatment of KPC mice with advanced PDAC reduced tumor burden by 80% and metastases by 87% after treatment and increased survival by 40% compared to nontreated mice. These results suggest that Listeria-delivered recall antigens could be an alternative to neoantigen-mediated cancer immunotherapy.

Human papilloma virus (HPV) infections are associated with almost all cervical cancers and to a lower extend also with anogenital or oropharyngeal cancers. HPV proteins expressed in HPV-associated tumors are attractive antigens for cancer vaccination strategies as self-tolerance, which is associated with most endogenous tumor-associated antigens, does not need to be overcome. In this study, we generated a live attenuated cancer vaccine based on the chimeric vesicular stomatitis virus VSV-GP, which has previously proven to be a potent vaccine vector and oncolytic virus. Genes at an earlier position in the genome more to the 3' end are expressed stronger compared to genes located further downstream. By inserting an HPV16-derived antigen cassette consisting of E2, E6 and E7 into VSV-GP either at first (HPVp1) or fifth (HPVp5) position in VSV-GP's genome we aimed to analyze the effect of vaccine antigen position and consequently expression level on viral fitness, immunogenicity, and anti-tumoral efficacy in a syngeneic mouse tumor model. HPVp1 expressed higher amounts of HPV antigens compared to HPVp5 in vitro but had a slightly delayed replication kinetic which overall translated into increased HPV-specific T cell responses upon vaccination of mice. Immunization with both vectors protected mice in prophylactic and in therapeutic TC-1 tumor models with HPVp1 being more effective in the prophylactic setting. Taken together, VSV-GP is a promising candidate as therapeutic HPV vaccine and first position of the vaccine antigen in a VSV-derived vector seems to be superior to fifth position.

Penile cancer (PC) is an extremely rare malignancy, and the patients at advanced stages have currently limited treatment options with disappointing results. Immune checkpoint inhibitors anti-programmed cell death 1 (PD-1)/programmed cell death ligand 1 (PD-L1) are currently changing the treatment of several tumors. Furthermore, the microsatellite instability (MSI) and the deficient mismatch repair system (dMMR) proteins represent predictive biomarkers for response to immune checkpoint therapy. Until present, few data have been reported related to PD-L1 expression and MSI in PC. The main aim of our study was the evaluation of PD-L1 expression in tumor cells (TCs) and tumor-infiltrating lymphocytes (TILs) in immune cells and the analysis of dMMR/MSI status in a large series of PCs.A series of 72 PC, including 65 usual squamous cell carcinoma (USCC), 1 verrucous, 4 basaloid, 1 warty, and 1 mixed (warty-basaloid), was collected. Immunohistochemistry (IHC) was performed to assess PD-L1 expression using two different anti-PD-L1 antibodies (clone SP263 and SP142 Ventana) and MMR proteins expression using anti-MLH1, anti-PMS2, anti-MSH2, and anti-MSH6 antibodies. PCR analysis was performed for the detection of MSI status.Of the 72 PC cases analyzed by IHC, 45 (62.5%) cases were TC positive and 57 (79%) cases were combined positive score (CPS) using PDL1 SP263. In our cohort, TILs were present in 62 out of 72 cases (86.1%), 47 (75.8%) out of 62 cases showed positivity to PDL1 clone SP142. In our series, 59 cases (82%) had pMMR, 12 cases (16.7%) had lo-paMMR, and only 1 case (1.3%) had MMR. PCR results showed that only one case lo-paMMR was MSI-H, and the case dMMR by IHC not confirmed MSI status.Our findings showed that PD-L1 expression and MSI status represent frequent biological events in this tumor suggesting a rationale for a new frontier in the treatment of patients with PC based on the immune checkpoint inhibitors.