Human immunodeficiency virus and human papilloma virus - why HPV-induced lesions do not spontaneously resolve and why therapeutic vaccination can be successful

HIV and HPV can both cause chronic infections and are acquired during sexual contact. HIV infection results in a progressive loss of CD4+ T cells that is associated with an increased prevalence of HPV infections, type-specific persistence and an increase in HPV-associated malignancies. On the one hand this illustrates the important role of HPV-specific CD4+ helper T-cell immunity, on the other it shows the Achilles heel of the HPV-specific immune response. The use of highly active antiretroviral therapy (HAART) results in a rapid reduction of HIV and a reconstitution of systemic CD4+ T-cell levels. The use of HAART thus has the potential to raise immunity to HPV but to the surprise of many, the incidence of HPV-induced diseases has increased rather than declined since the introduction of HAART. Here, the knowledge on how HPV-induced diseases develop in the face of a non-compromised immune system will be used to explain why the effect of HAART on HPV-induced diseases is modest at best. Furthermore, exciting new data in the field of therapeutic vaccines against HPV will be discussed as this may form a more durable and clinically successful therapeutic approach for the treatment of HPV-induced high-grade lesions in HIV-positive subjects on HAART

Toward harmonized phenotyping of human myeloid-derived suppressor cells by flow cytometry: results from an interim study

There is an increasing interest for monitoring circulating myeloid-derived suppressor cells (MDSCs) in cancer patients, but there are also divergences in their phenotypic definition. To overcome this obstacle, the Cancer Immunoguiding Program under the umbrella of the Association of Cancer Immunotherapy is coordinating a proficiency panel program that aims at harmonizing MDSC phenotyping. After a consultation period, a two-stage approach was designed to harmonize MDSC phenotype. In the first step, an international consortium of 23 laboratories immunophenotyped 10 putative MDSC subsets on pretested, peripheral blood mononuclear cells of healthy donors to assess the level of concordance and define robust marker combinations for the identification of circulating MDSCs. At this stage, no mandatory requirements to standardize reagents or protocols were introduced. Data analysis revealed a small intra-laboratory, but very high inter-laboratory variance for all MDSC subsets, especially for the granulocytic subsets. In particular, the use of a dead-cell marker altered significantly the reported percentage of granulocytic MDSCs, confirming that these cells are especially sensitive to cryopreservation and/or thawing. Importantly, the gating strategy was heterogeneous and associated with high inter-center variance. Overall, our results document the high variability in MDSC phenotyping in the multicenter setting if no harmonization/standardization measures are applied. Although the observed variability depended on a number of identified parameters, the main parameter associated with variation was the gating strategy. Based on these findings, we propose further efforts to harmonize marker combinations and gating parameters to identify strategies for a robust enumeration of MDSC subsets

Interferon-gamma and IL-5 associated cell-mediated immune responses to HPV16 E2 and E6 distinguish between persistent oral HPV16 infections and noninfected mucosa

Objectives: Natural history of human papillomavirus (HPV) infection in the head and neck region is poorly understood, and their impact on collective HPV-specific immunity is not known. Materials and methods: In this study, we have performed a systematic analysis of HPV16-specific cell-mediated immunity (CMI) in 21 women with known oral and genital HPV DNA status and HPV serology (Ab) based on 6-year follow-up data. These women being a subgroup from the Finnish Family HPV Study were recalled for blood sampling to be tested for their CMI-responses to HPV16 E2, E6, and E7 peptides. Results: The results showed that HPV16 E2-specific lymphocyte proliferation was more prevalent in women who tested HPV16 DNA negative in oral mucosa and were either HPV16 seropositive or negative than in HPV16 DNA+/Ab+ women (p = 0.046 and p = 0.035). In addition, the HPV16 DNA-/Ab- women most often displayed E6-specific proliferation (p = 0.020). Proportional cytokine profiles indicated that oral HPV16-negative women were characterized by prominent IFN-gamma and IL-5 secretion not found in women with persisting oral HPV16 (p = 0.014 and p = 0.040, respectively). Conclusions: Our results indicate that the naturally arising immune response induced by oral HPV infections displays a mixed Th1/Th2/Th17 cytokine profile while women with persisting oral HPV16 might have an impaired HPV16-specific CMI, shifted partly toward a Th2 profile, similarly as seen earlier among patients with high-grade genital HPV lesions. Thus, the lack of HPV 16 E2 and E6 specific T memory cells and Th2 cytokines might also predispose women for persistent oral HPV16 infection which might be related to the risk of cancer.Peer reviewe

Features of effective T Cell-inducing vaccines against Chronic viral infections

Tumorimmunolog

Generating HPV specific T helper cells for the treatment of HPV induced malignancies using TCR gene transfer

<p>Abstract</p> <p>Background</p> <p>Infection with high risk Human Papilloma Virus (HPV) is associated with cancer of the cervix, vagina, penis, vulva, anus and some cases of head and neck carcinomas. The HPV derived oncoproteins E6 and E7 are constitutively expressed in tumor cells and therefore potential targets for T cell mediated adoptive immunotherapy. Effective immunotherapy is dependent on the presence of both CD4+ and CD8+ T cells. However, low precursor frequencies of HPV16 specific T cells in patients and healthy donors hampers routine isolation of these cells for adoptive transfer purposes. An alternative to generate HPV specific CD4+ and CD8+ T cells is TCR gene transfer.</p> <p>Methods</p> <p>HPV specific CD4+ T cells were generated using either a MHC class I or MHC class II restricted TCR (from clones A9 and 24.101 respectively) directed against HPV16 antigens. Functional analysis was performed by interferon-γ secretion, proliferation and cytokine production assays.</p> <p>Results</p> <p>Introduction of HPV16 specific TCRs into blood derived CD4+ recipient T cells resulted in recognition of the relevant HPV16 epitope as determined by IFN-γ secretion. Importantly, we also show recognition of the endogenously processed and HLA-DP1 presented HPV16E6 epitope by 24.101 TCR transgenic CD4+ T cells and recognition of the HLA-A2 presented HPV16E7 epitope by A9 TCR transgenic CD4+ T cells.</p> <p>Conclusion</p> <p>Our data indicate that TCR transfer is feasible as an alternative strategy to generate human HPV16 specific CD4+ T helper cells for the treatment of patients suffering from cervical cancer and other HPV16 induced malignancies.</p

Human Papillomavirus Deregulates the Response of a Cellular Network Comprising of Chemotactic and Proinflammatory Genes

Despite the presence of intracellular pathogen recognition receptors that allow infected cells to attract the immune system, undifferentiated keratinocytes (KCs) are the main targets for latent infection with high-risk human papilloma viruses (hrHPVs). HPV infections are transient but on average last for more than one year suggesting that HPV has developed means to evade host immunity. To understand how HPV persists, we studied the innate immune response of undifferentiated human KCs harboring episomal copies of HPV16 and 18 by genome-wide expression profiling. Our data showed that the expression of the different virus-sensing receptors was not affected by the presence of HPV. Poly(I:C) stimulation of the viral RNA receptors TLR3, PKR, MDA5 and RIG-I, the latter of which indirectly senses viral DNA through non-self RNA polymerase III transcripts, showed dampening in downstream signalling of these receptors by HPVs. Many of the genes downregulated in HPV-positive KCs involved components of the antigen presenting pathway, the inflammasome, the production of antivirals, pro-inflammatory and chemotactic cytokines, and components downstream of activated pathogen receptors. Notably, gene and/or protein interaction analysis revealed the downregulation of a network of genes that was strongly interconnected by IL-1β, a crucial cytokine to activate adaptive immunity. In summary, our comprehensive expression profiling approach revealed that HPV16 and 18 coordinate a broad deregulation of the keratinocyte's inflammatory response, and contributes to the understanding of virus persistence

The nonpolymorphic MHC Qa-1b mediates CD8+ T cell surveillance of antigen-processing defects

The nonclassical major histocompatibility complex (MHC) Qa-1b accommodates monomorphic leader peptides and functions as a ligand for germ line receptors CD94/NKG2, which are expressed by natural killer cells and CD8+ T cells. We here describe that the conserved peptides are replaced by a novel peptide repertoire of surprising diversity as a result of impairments in the antigen-processing pathway. This novel peptide repertoire represents immunogenic neoantigens for CD8+ T cells, as we found that these Qa-1b–restricted T cells dominantly participated in the response to tumors with processing deficiencies. A surprisingly wide spectrum of target cells, irrespective of transformation status, MHC background, or type of processing deficiency, was recognized by this T cell subset, complying with the conserved nature of Qa-1b. Target cell recognition depended on T cell receptor and Qa-1b interaction, and immunization with identified peptide epitopes demonstrated in vivo priming of CD8+ T cells. Our data reveal that Qa-1b, and most likely its human homologue human leukocyte antigen-E, is important for the defense against processing-deficient cells by displacing the monomorphic leader peptides, which relieves the inhibition through CD94/NKG2A on lymphocytes, and by presenting a novel repertoire of immunogenic peptides, which recruits a subset of cytotoxic CD8+ T cells

Spontaneous tumor rejection by cbl-b–deficient CD8+ T cells

The concept of tumor surveillance implies that specific and nonspecific components of the immune system eliminate tumors in the early phase of malignancy. Understanding the biochemical mechanisms of tumor immunosurveillance is of paramount significance because it might allow one to specifically modulate spontaneous antitumor activity. We report that inactivation of the E3 ligase Casitas B cell lymphoma-b (Cbl-b) confers spontaneous in vivo rejection of tumor cells that express human papilloma virus antigens. Moreover, cbl-b−/− mice develop significantly fewer ultraviolet B (UVB)–induced skin malignancies and reject UVB-induced skin tumors. CD8+ T cells were identified as key players in the spontaneous tumor rejection response. Loss of Cbl-b not only enhances antitumor reactivity of CD8+ T cells but also occurs in the absence of CD4+ T cells. Mechanistically, cbl-b−/− CD8+ T cells are resistant to T regulatory cell–mediated suppression and exhibit enhanced activation and rapid tumor infiltration. Importantly, therapeutic transfer of naive cbl-b−/− CD8+ T cells is sufficient to mediate rejection of established tumors. Even up to 1 yr after the first encounter with the tumor cells, cbl-b−/− mice carry an “anticancer memory.” These data identify Cbl-b as a key signaling molecule that controls spontaneous antitumor activity of cytotoxic T cells in different cancer models. Inhibition of Cbl-b is a novel approach to stimulate long-lasting immunity against cancer

Genetic evolution of uveal melanoma guides the development of an inflammatory microenvironment

Experimental cancer immunology and therap