T-cell response to human papillomavirus type 58 L1, E6, And E7 peptides in women with cleared infection, cervical intraepithelial neoplasia, or invasive cancer

Cellular immune responses against natural human papillomavirus infections among men in Kisumu, Kenya

Human papillomavirus (HPV) is associated with ano-genital and cervical cancer. Persistence of oncogenic HPV genotypes is a requirement for development and progression of malignancies. Although, >70% of women clear incident HPV infections, data on natural history and HPV immunology among men is limited. To evaluate cell-mediated immune responses to natural HPV infections among men, we assessed cytokine responses on PBMCs collected from men with persistent or cleared HPV. Men with HPV clearance and those with HPV persistence had increased odds (6-times and 3-times respectively) of mounting cytokine responses compared to HPV uninfected men. Th1 cytokines IFN-γ (5.1-fold) and IL-2 (4.2-fold) were significantly (p < 0.0001) upregulated among men with HPV clearance compared to HPV uninfected men. Among men with HPV clearance compared to those with persistent HPV infection, only IFN-γ (2.4-fold) and IL-2 (3.0-fold) were significantly (p < 0.0001) upregulated. Th1 cell-mediated cytokine response was associated with natural HPV clearance in men.

Exploring the Papillomaviral Proteome to Identify Potential Candidates for a Chimeric Vaccine against Cervix Papilloma Using Immunomics and Computational Structural Vaccinology

The human papillomavirus (HPV) 58 is considered to be the second most predominant genotype in cervical cancer incidents in China. HPV type-restriction, non-targeted delivery, and the highcost of existing vaccines necessitate continuing research on the HPV vaccine. We aimed to explore the papillomaviral proteome in order to identify potential candidates for a chimeric vaccine against cervix papilloma using computational immunology and structural vaccinology approaches. Two overlapped epitope segments (23⁻36) and (29⁻42) from the N-terminal region of the HPV58 minor capsid protein L2 are selected as capable of inducing both cellular and humoral immunity. In total, 318 amino acid lengths of the vaccine construct SGD58 contain adjuvants (Flagellin and RS09), two Th epitopes, and linkers. SGD58 is a stable protein that is soluble, antigenic, and non-allergenic. Homology modeling and the structural refinement of the best models of SGD58 and TLR5 found 96.8% and 93.9% favored regions in Rampage, respectively. The docking results demonstrated a HADDOCK score of -62.5 ± 7.6, the binding energy (-30 kcal/mol) and 44 interacting amino acid residues between SGD58-TLR5 complex. The docked complex are stable in 100 ns of simulation. The coding sequences of SGD58 also show elevated gene expression in Escherichia coli with 1.0 codon adaptation index and 59.92% glycine-cysteine content. We conclude that SGD58 may prompt the creation a vaccine against cervix papilloma.

Investigating the aetiology of adverse events following HPV vaccination with systems vaccinology

In contrast to the insidious and poorly immunogenic human papillomavirus (HPV) infections, vaccination with the HPV virus-like particles (vlps) is non-infectious and stimulates a strong neutralizing-antibody response that protects HPV-naïve vaccinees from viral infection and associated cancers. However, controversy about alleged adverse events following immunization (AEFI) with the vlps have led to extensive reductions in vaccine acceptance, with countries like Japan dropping it altogether. The AEFIs are grouped into chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME). In this review, we present a hypothesis that the AEFIs might arise from malfunctions within the immune system when confronted with the unusual antigen. In addition, we outline how the pathophysiology of the AEFIs can be cost-effectively investigated with the holistic principles of systems vaccinology in a two-step process. First, comprehensive immunological profiles of HPV vaccinees exhibiting the AEFIs are generated by integrating the data derived from serological profiling for prominent HPV antibodies and serum cytokines, with data from serum metabolomics, peripheral white blood cells transcriptomics and gut microbiome profiling. Next, the immunological profiles are compared with corresponding profiles generated for matched (a) HPV vaccinees without AEFIs; (b) non-HPV-vaccinated individuals with CFS/ME-like symptoms; and (c) non-HPV-vaccinated individuals without CFS/ME. In these comparisons, any causal links between HPV vaccine and the AEFIs, as well as the underlying molecular basis for the links will be revealed. Such a study should provide an objective basis for evaluating HPV vaccine safety and for identifying biomarkers for individuals at risk of developing AEFI with HPV vaccination.

Prediction and identification of human leukocyte antigen-A2-restricted cytotoxic T lymphocyte epitope peptides from the human papillomavirus 58 E7 protein

Persistent infection with high-risk human papilloma virus (HPV) is the primary cause of cervical intraepithelial neoplasia (CIN) and cervical carcinoma. HPV58 is the third most common HPV genotype in China after HPV16 and HPV18. HPV E6 and E7 are oncoproteins and are constitutively expressed in HPV-associated cancer cells, therefore they are considered to be ideal target antigens for immunotherapy, including HPV therapeutic vaccine. In the present study, human leukocyte antigen (HLA)-A2-restricted cytotoxic T lymphocyte (CTL) epitope peptides were predicted and screened from HPV58 E7 antigen and their immunogenicity was subsequently determined. A total of 6 HLA-A2-binding peptides derived from HPV58 E7 were predicted and selected using 3 different prediction programs. A negative control peptide and PBS were used as two negative controls. Peripheral blood mononuclear cells (PBMCs) with HLA-A2(+) allele were used to detect the specific cellular immune response among the 6 predicted peptides by enzyme-linked immunospot assay (ELISOPT). Following preliminary screening for the predicted peptides, the antigenicity of the peptide HPV58 E7_72-80 was further assessed by an immunoassay to a vaccine contained HPV58 E7 antigen. Specific humoral and cellular immunity were detected using the peptide HPV58 E7_72-80 as the specific antigen. A total of 6 peptides from HPV58 E7 protein were predicted and subsequently named P1 (E7_7-15: TLREYILDL), P2 (E7_14-22: DLHPEPTDL), P3 (E7_69-77: CINSTTTDV), and P4 (E7_72-80: STTTDVRTL), P5 (E7_79-87: TLQQLLMGT) and P6 (E7_83-91: LLMGTCTIV). In the ELISPOT assay on HLA-A2 (+) human PBMCs, interferon (IFN)-γ-production was evident in the P2 and P4 groups. The average numbers of IFN-γ associated spots in the P2 and P4 groups was 50.61±5.37 spot-forming cells (SFC)/1×10⁵ and 266±34.42 SFC/1×10⁵, respectively. The numbers of spots in the two peptides were significantly increased compared with the other 4 peptides and the control groups (P<0.05). In the further antigenicity verification of P4 (HPV58 E7_72-80), the peptide only stimulated the humoral immune response of the AD-HPV16/18/58 mE6E7 vaccine containing HPV58 E7 antigen. Compared with the 2 negative control groups (1:400), the antibody titers of the vaccine group (1:25,600) were significantly increased (P<0.05). In cellular immunoassays the average number of IFN-γ associated spots was 143.3±32.13 SFC/1×10⁵ in the vaccine group, which was significantly enhanced compared with the PBS group (8±5.29 SFC/1×10⁵; P<0.01) and the AD-NC group (28±5.13 SFC/1×10⁵; P<0.01). The peptide HPV58 E7_72-80 (STTTDVRTL) displayed sufficient antigenicity to a vaccine contained HPV58 E7 antigen. Therefore, HPV58 E7_72-80 peptide may be considered as a candidate epitope peptide for the construction of HPV58 peptide vaccines.

Beta emitters rhenium-188 and lutetium-177 are equally effective in radioimmunotherapy of HPV-positive experimental cervical cancer

Cervical cancer caused by the infection with the human papillomavirus (HPV) remains the fourth leading killer of women worldwide. Therefore, more efficacious treatments are needed. We are developing radioimmunotherapy (RIT) of HPV‐positive cervical cancers by targeting E6 and E7 viral oncoproteins expressed by the cancer cells with the radiolabeled monoclonal antibodies (mAbs). To investigate the influence of different radionuclides on the RIT efficacy—we performed RIT of experimental cervical cancer with Rhenium‐188 (¹⁸⁸Re) and Lutetium‐177 (¹⁷⁷Lu)‐labeled mAb C1P5 to E6. The biodistribution of ¹⁸⁸Re‐ and ¹⁷⁷Lu‐labeled C1P5 was performed in nude female mice bearing CasKi cervical cancer xenografts and the radiation dosimetry calculations for the tumors and organs were carried out. For RIT the mice were treated with 7.4 MBq of either ¹⁸⁸Re‐C1P5 or ¹⁷⁷Lu‐C1P5 or left untreated, and observed for their tumor size for 28 days. The levels of ¹⁸⁸Re‐ and ¹⁷⁷Lu‐C1P5 mAbs‐induced double‐strand breaks in CasKi tumors were compared on days 5 and 10 post treatment by staining with anti‐gamma H2AX antibody. The radiation doses to the heart and lungs were similar for both ¹⁷⁷Lu‐C1P5 and ¹⁸⁸Re‐C1P5. The dose to the liver was five times higher for ¹⁷⁷Lu‐C1P5. The doses to the tumor were 259 and 181 cGy for ¹⁷⁷Lu‐C1P5 and ¹⁸⁸Re‐C1P5, respectively. RIT with either ¹⁷⁷Lu‐C1P5 or ¹⁸⁸Re‐C1P5 was equally effective in inhibiting tumor growth when each was compared to the untreated controls (P = 0.001). On day 5 there was a pronounced staining for gamma H2AX foci in ¹⁷⁷Lu‐C1P5 group only and on day 10 it was observed in both ¹⁷⁷Lu‐C1P5 and ¹⁸⁸Re‐C1P5 groups. ¹⁸⁸Re‐ and ¹⁷⁷Lu‐labeled mAbs were equally effective in arresting the growth of CasKi cervical tumors. Thus, both of these radionuclides are candidates for the clinical trials of this approach in patients with advanced, recurrent or metastatic cervical cancer.

Depletion of tumor-associated macrophages enhances the anti-tumor immunity induced by a Toll-like receptor agonist-conjugated peptide

It has been reported that lipopeptides can be used to elicit cytotoxic T lymphocyte (CTL) responses against viral diseases and cancer. In our previous study, we determined that mono-palmitoylated peptides can enhance anti-tumor responses in the absence of adjuvant activity. To investigate whether di-palmitoylated peptides with TLR2 agonist activity are able to induce anti-tumor immunity, we synthesized a di-palmitic acid-conjugated long peptide that contains a murine CTL epitope of HPV E7_49–57 (Pam2IDG). Pam2IDG stimulated the maturation of bone marrow-derived dendritic cells (BMDCs) through TLR2/6. After immunization, Pam2IDG induced higher levels of T cell responses than those obtained with its non-lipidated counterpart (IDG). In the prophylactic model, Pam2IDG immunization completely inhibited tumor growth, whereas IDG immunization was unable to inhibit tumor growth. However, Pam2IDG immunization could not effectively inhibit the growth of established tumors. Therefore, we further investigated whether the depletion of immunosuppressive factors could improve the therapeutic effects of Pam2IDG. Our data indicate that treatment with Pam2IDG combined with clodronate/liposome delays tumor growth and increases the survival rate. We also observed that the therapeutic effects of Pam2IDG are improved by diminishing the function of tumor-associate macrophages (TAMs) and through the use of an IL10 receptor blocking antibody or a Cyclooxygenase 2 (Cox-2) inhibitor. In conclusion, the depletion of TAMs may enhance the anti-tumor immunity of a TLR2 agonist-conjugated peptide.