Papillomavirus-Specific CD4+ T Cells Exhibit Reduced STAT-5 Signaling and Altered Cytokine Profiles in Patients with Recurrent Respiratory Papillomatosis

Abstract

Recurrent Respiratory Papillomatosis (RRP) is caused by HPV-6 or -11. Specific HLA-DR haplotypes, DRB1*01:02 and DRB1*03:01 are associated with the development of RRP, disease severity, and TH2-like responses to HPV early proteins. TH1-like responses to HPV proteins have been shown to be protective in animal models. Therefore, we investigated the hypothesis that RRP patients have dysfunctional TH1-like HPV-specific T-cell responses. Using MHC class II tetramers, we identified immunogenic peptides within HPV-11 early proteins. Two distinct peptides (E6113-132 and E21-20) contained DRB1*01:02 or DRB1*03:01 restricted epitopes respectively. An additional peptide (E2281-300) contained an epitope presented by both alleles. Peptide binding, tetramer, and proliferation assays identified minimal epitopes within these peptides. These epitopes elicited E2/E6 specific CD4+ T-cell responses in RRP patients and healthy controls, allowing the isolation of HPV-specific T-cell lines using tetramers. The cytokine profiles and STAT signaling of these tetramer-positive T-cells were measured to compare the polarization and responsiveness of HPV-specific T-cells from patients with RRP and healthy subjects. HPV-specific IFN-γ secretion was substantially lower in T-cells from RRP patients. HPV-specific IL-13 secretion was seen at modest levels in T-cells from RRP patients and absent in T-cells from healthy controls. HPV-specific T-cells from RRP patients exhibited reduced STAT-5 phosphorylation and reduced IL-2 secretion, suggesting anergy. Levels of STAT-5 phosphorylation and IFN-γ secretion could be improved through addition of IL-2 to HPV-specific T-cell lines from RRP patients. Therapeutic vaccination or interventions aimed at restoring TH1-like cytokine responses to HPV proteins and reversing anergy could improve clinical outcomes for RRP patients.

MHC Class II Tetramers

“…Monitoring immunity to infectious pathogens. Class II tetramers have been used for analysis of a variety of human CD4 T cell responses to pathogens, including influenza A, Borrelia, EBV, CMV, Mycobacterium tuberculosis, human T-lymphotropic virus 1, hepatitis C, anthrax, severe acute respiratory syndrome virus, human papillomavirus, and HIV (3,7,(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30). Ag-specific T cells are detected in peripheral blood, with a very broad range of frequency, depending on prior Ag exposure, vaccination history, and timing of immunization.…”

Using an adaptive gene network model for self-organizing multicellular behavior

“…Among different gene network motifs, an incoherent type 1 feed forward loop is known to create a pulse-like transient behavior and it is unlikely that cells utilize a negative feedback motif to generate such behavior [29]. Furthermore, a recent study reports that pSTAT5 may increase IL-2 secretion indicating that there can also be a positive feedback mechanism involved [30]. …”

“…First, negative feedback is not appropriate for generating a pulse-like, transient behavior [29]. Second, both negative and positive feedback mechanisms have been reported [30] and these mechanisms may be differentially used under different conditions although they are not completely understood [11]. Third, the negative feedback model cannot explain the termination of IL-2 production/secretion in the presence of sustained antigenic stimulus [26].…”

Altered Monocyte and Langerhans Cell Innate Immunity in Patients With Recurrent Respiratory Papillomatosis (RRP)

“…This suggests that the balance of proinflammatory vs. anti-inflammatory immune mediators and cells within the papilloma microenvironment is altered to support persistence of HPV6/11 infection, following activation of latent infection, with subsequent papilloma recurrence (8,(11)(12)(13)(14)(15). We previously showed that T-cell responses to autologous papilloma tissue and to HPV6/11 early proteins are polarized away from effective viral control (8,11,14), likely secondary to functional PD1 + /CD4 + Tregs in these lesions (15). In addition, CD8 + /CD28 − T cells that express granzyme are present in papillomas but fail to function as mature cytotoxic T lymphocytes (CTLs) (8).…”