Isolation and characterization of human papillomavirus type 6-specific T cells infiltrating genital warts

Single-Cell RNAseq Profiling of Human γδ T Lymphocytes in Virus-Related Cancers and COVID-19 Disease

The detailed characterization of human γδ T lymphocyte differentiation at the single-cell transcriptomic (scRNAseq) level in tumors and patients with coronavirus disease 2019 (COVID-19) requires both a reference differentiation trajectory of γδ T cells and a robust mapping method for additional γδ T lymphocytes. Here, we incepted such a method to characterize thousands of γδ T lymphocytes from (n = 95) patients with cancer or adult and pediatric COVID-19 disease. We found that cancer patients with human papillomavirus-positive head and neck squamous cell carcinoma and Epstein-Barr virus-positive Hodgkin's lymphoma have γδ tumor-infiltrating T lymphocytes that are more prone to recirculate from the tumor and avoid exhaustion. In COVID-19, both TCRVγ9 and TCRVγnon9 subsets of γδ T lymphocytes relocalize from peripheral blood mononuclear cells (PBMC) to the infected lung tissue, where their advanced differentiation, tissue residency, and exhaustion reflect T cell activation. Although severe COVID-19 disease increases both recruitment and exhaustion of γδ T lymphocytes in infected lung lesions but not blood, the anti-IL6R therapy with Tocilizumab promotes γδ T lymphocyte differentiation in patients with COVID-19. PBMC from pediatric patients with acute COVID-19 disease display similar γδ T cell lymphopenia to that seen in adult patients. However, blood γδ T cells from children with the COVID-19-related multisystem inflammatory syndrome are not lymphodepleted, but they are differentiated as in healthy PBMC. These findings suggest that some virus-induced memory γδ T lymphocytes durably persist in the blood of adults and could subsequently infiltrate and recirculate in tumors.

Prognostic significance of immunohistochemical phenotypes in patients treated for high-grade cervical intraepithelial neoplasia

Strong evidence exists that the host's immune system plays a crucial role for the development of human papillomavirus-related cervical premalignant and malignant lesions. In particular, effective cell-mediated immunity (CMI) promotes spontaneous infection clearance and cancer precursors regression in healthy subjects, while immunosuppressed individuals are more likely to experience infection persistence, cervical intraepithelial neoplasia (CIN) lesions, and cervical cancer. In this study, the prognostic significance of immunohistochemical profiling of CD4+ T-cells, CD8+ T-cells, dendritic cells (CD11c+), T-bet+, and GATA-3+ transcription factors has been studied in surgical specimens of 34 consecutive women affected by high-grade cervical intraepithelial neoplasia (CIN2-3) submitted to cervical conization. Results have been correlated with the clinical outcomes at 24 months after treatment and statistically analyzed. Higher rates of CD4+ T-cells, CD11c+ dendritic cells, and T-bet+ transcription factor positivity showed a strong statistically significative correlation with favourable clinical outcomes (P ≤ 0.0001). These data reinforce the evidence of the relevance of the host's immune status in the natural history of HPV-related cervical disease and add a prognostic significance of the cervical immunological profile in terms of predicting significant lower recurrence rates.

Expression of dendritic cell lysosome-associated membrane protein and dendritic cell-specific intercellular adhesion molecule-3 grabbing nonintegrin in condyloma acuminatum lesions

OBJECTIVE

Retrospective, observational study to explore the role of dendritic cells (DCs) in condyloma acuminatum lesions (genital warts) and their relationship with duration of the disease.

METHODS

Condyloma acuminatum lesion samples were collected from male patients with the condition and compared with normal foreskin samples from male volunteers. Cellular locations of dendritic cell lysosome-associated membrane protein (DC-LAMP) and dendritic cell-specific intercellular adhesion molecule-3 grabbing nonintegrin (DC-SIGN) were detected using immunohistochemistry. Levels of both proteins were determined using Western blot analysis; levels of their corresponding mRNAs were measured using reverse transcription-polymerase chain reaction.

RESULTS

The mRNA and protein levels of DC-LAMP and DC-SIGN were both significantly higher in condyloma acuminatum lesions (n = 30 samples) compared with normal skin samples (n = 13). Levels of DC-LAMP and DC-SIGN protein and duration of disease were inversely correlated.

CONCLUSIONS

DC-LAMP and DC-SIGN may be involved in the pathogenesis of condyloma acuminatum. Their levels were inversely correlated with the duration of disease, suggesting that DCs might be involved in human papillomavirus clearance.

[CD4 and CD8 T lymphocytes and NK cells in the stroma of the uterine cervix of women infected with human papillomavirus]

INTRODUCTION

Immune response might be a key element regarding the progression or regression of human papillomavirus (HPV) infection in the stroma of the uterine cervix. This study aimed to quantify the presence of CD4 and CD8 T lymphocytes and NK cells in the cervical stroma, by means of immunohistochemistry, in high and low grade lesions in patients infected by HPV METHODS: Fifty-six biopsy samples from the uterine cervix were used. Forty-three samples were positive for oncogenic high-risk HPV DNA and had a histopathological diagnosis of high and low-grade cervical intraepithelial neoplasia (CIN) or negative for intraepithelial lesion and malignancy (NILM); while the other 13 samples were negative for HPV DNA with a histopathological diagnosis of NILM RESULTS: Higher quantities of CD4 T lymphocytes were observed in CIN II/III, carcinoma and NILM samples (p = 0.04) and in those in which the viral load was between 10 and 1.000 RLU/PCB. CD8 T lymphocytes were predominant in CIN II/III samples (p = 0.02) and also in samples with viral loads between 100 and 1,000 RLU/PCB. NK cells predominated in samples with low-grade lesions and low viral load

CONCLUSIONS

This study proved that in the initial stages of the infection, in which no high-grade cell abnormalities have yet occurred, no cells that might trigger the effector phase of the immune response.

Genital warts and infection with human immunodeficiency virus in high-risk women in Burkina Faso: a longitudinal study

Background

Human papillomaviruses are the most common sexually transmitted infections, and genital warts, caused by HPV-6 and 11, entail considerable morbidity and cost. The natural history of genital warts in relation to HIV-1 infection has not been described in African women. We examined risk factors for genital warts in a cohort of high-risk women in Burkina Faso, in order to further describe their epidemiology.

Methods

A prospective study of 765 high-risk women who were followed at 4-monthly intervals for 27 months in Burkina Faso. Logistic and Cox regression were used to identify factors associated with prevalent, incident and persistent genital warts, including HIV-1 serostatus, CD4+ count, and concurrent sexually transmitted infections. In a subset of 306 women, cervical HPV DNA was tested at enrolment.

Results

Genital wart prevalence at baseline was 1.6% (8/492) among HIV-uninfected and 7.0% (19/273) among HIV-1 seropositive women. Forty women (5.2%) experienced at least one incident GW episode. Incidence was 1.1 per 100 person-years among HIV-uninfected women, 7.4 per 100 person-years among HIV-1 seropositive women with a nadir CD4+ count >200 cells/μL and 14.6 per 100 person-years among HIV-1 seropositive women with a nadir CD4+ count ≤200 cells/μL. Incident genital warts were also associated with concurrent bacterial vaginosis, and genital ulceration. Antiretroviral therapy was not protective against incident or persistent genital warts. Detection of HPV-6 DNA and abnormal cervical cytology were strongly associated with incident genital warts.

Conclusions

Genital warts occur much more frequently among HIV-1 infected women in Africa, particularly among those with low CD4+ counts. Antiretroviral therapy did not reduce the incidence or persistence of genital warts in this population.

Local hyperthermia could induce antiviral activity by endogenous interferon-dependent pathway in condyloma acuminata

Local hyperthermia has been successfully used in the treatment of viral warts by mechanisms that have largely remained unclear. Using an organotypic culture system, we found that hyperthermia at 42 °C and 45 °C could induce a significant increase in the transcriptional expression of interferon (IFN)-α, IFN-β and IFN-γ, in a temperature-dependent manner in condyloma acuminata (CA), but not in normal skin. Accordingly, local hyperthermia could enhance the expression of 2'-5' oligoadenylate synthase and double-stranded RNA (dsRNA)-dependent protein kinase, two antiviral enzymes downstream of the IFN-dependant pathway. Hyperthermia led to an increase in IFN-α/β receptor transcripts, and an increase in the levels in phospho-Stat1 and phospho-Stat2 in CA, though it had no influence on the levels of Jak1, Tyk2, Stat1 and Stat2 transcriptional expression. Local hyperthermia was proved effective in treating human papillomavirus-infected skin. These results suggested that hyperthermia took effect partly by inducing the expression of local endogenous IFN and partly by subsequent IFN-induced antiviral activity via Jak-STATs signalling pathway in CA.

Cross-protective responses to human papillomavirus infection

Human papillomavirus (HPV) infections with oncogenic types account for approximately 500,000 deaths per year worldwide, predominantly in underdeveloped countries. The major cause of death is cervical cancer in women, but some additional cancers of the head and neck and anogenital sites also have an HPV etiology. Current virus-like particle-based vaccines are in clinical trials, and show very strong, long-lasting protection against vaccine-matched HPV types. These vaccines currently contain virus-like particles for the HPV types 6, 11, 16 and 18 (Gardasil®) and HPV16 and -18 (Cervarix®). Although type-specific neutralizing antibodies develop from immunizations with these virus-like particle vaccines, promising evidence for cross-protection against related but nonvaccine HPV types is emerging. Strategies to increase cross-protection to cover all oncogenic HPV types (currently approximately 20 types) are underway. These strategies include increasing the number of HPV types in the virus-like particle vaccine, and to the development of second-generation HPV vaccines that include the minor coat protein.

Smoking enhances risk for new external genital warts in men

Repeat episodes of HPV-related external genital warts reflect recurring or new infections. No study before has been sufficiently powered to delineate how tobacco use, prior history of EGWs and HIV infection affect the risk for new EGWs. Behavioral, laboratory and examination data for 2,835 Multicenter AIDS Cohort Study participants examined at 21,519 semi-annual visits were evaluated. Fourteen percent (391/2835) of men reported or were diagnosed with EGWs at 3% (675/21,519) of study visits. Multivariate analyses showed smoking, prior episodes of EGWs, HIV infection and CD4+ T-lymphocyte count among the infected, each differentially influenced the risk for new EGWs.

Characterising the local immune responses in cervical intraepithelial neoplasia: a cross-sectional and longitudinal analysis

INTRODUCTION

Immunological competence influences the progression of cervical intraepithelial neoplasia (CIN) to invasive cancer. Information on the local immunological changes during the natural course of CIN is central for the development of new therapies.

OBJECTIVE

This study defines the populations of tissue-infiltrating immune cells in a cross-sectional cohort of different grades of CIN and also in a longitudinal cohort of regressing, persistent and progressing low-grade (LG)-CIN.

DESIGN

A cohort of 125 women with LG cytological atypia was recruited, of which 64/125 (51%) women with LG-CIN were followed prospectively for 1 year. Paraffin-embedded entry and exit cervical biopsies were used for immunohistochemistry analysis (CD4, CD8, CD56, FOXP3, CD1a and granzyme B).

RESULTS

At recruitment, 74/125 (59%), 39/125 (31%) and 12/125 (10%) women referred with LG smears had histologically proven LG-CIN, high-grade (HG) and normal biopsies, respectively. Seventeen of 64 (24.6%) women with LG-CIN progressed to HG-CIN within 1 year. In both LG-CIN and HG-CIN, the predominant intraepithelial cell population were cytotoxic T cells, while CD4+ and FOXP3+ T cells predominated the stromal compartment. Women with LG-CIN who later on regressed displayed a significantly higher number of cytotoxic (granzyme B+) cells in their entry samples. In addition, the ratio between CD8+ cells and granzyme B+ cells was close to 1, suggesting that all infiltrating CD8+ T cells were highly active. In contrast, this ratio was three-fold lower in women, in whom the lesions persisted or progressed.

CONCLUSIONS

This study suggests that the early infiltration of lesions by highly cytotoxic effector cells protects against progression.

Local accumulation of FOXP3+ regulatory T cells: evidence for an immune evasion mechanism in patients with large condylomata acuminata

Condylomata acuminata derived from the infection of human papillomavirus is a common sexually transmitted disease. Although T cell-mediated cellular immunity is considered as the main arm against such infection, the regulation of T cell immune responses in genital condylomata is unclear to date. In this study, we analyzed FOXP3(+) regulatory T cells in genital condylomata of patients. The results show that FOXP3(+) regulatory T cells with suppressive function accumulated in large warts. Consistently, the immunosuppressive milieu in large warts was characterized by high expression of IL-10 and TGF-beta1 and low expression of IL-2 and IFN-gamma. The responsiveness of wart-infiltrating T cells both in vitro and in vivo can be increased by depleting FOXP3(+) T cells. The accumulation of FOXP3(+) regulatory T cells in large warts can be partly ascribed to the chemotaxis of CCL17 and CCL22, derived from Langerhans cells and macrophages in wart. Although such accumulation favors the local immunosuppression, it seems not to influence the systemic immunity. In conclusion, these findings demonstrate that FOXP3(+) regulatory T cells play an important role in genital condylomata, which has multiple implications in the comprehensive treatment of condylomata acuminata.

Local And Systemic Human Papillomavirus Type 6b-Specific Cellular Immune Responses in Patients with Recurrent Genital Warts

Anogenital warts are a common clinical manifestation of genital infection with human papillomavirus type 6b (HPV-6b). Accumulating data indicate that an effective cellular immune response is required for the control of HPV infections. However, in a minority of patients there is a high rate of recurrence of wart lesions. We report the characterization of both local and systemic HPV-specific cellular immune responses in three patients with a history of recurrent genital warts. Although the patients had chronic recurrent wart lesions, we have shown that each had both detectable intralesional and peripheral HPV-specific T lymphocytes. Interestingly, the lesion-infiltrating T cells were specific for only one HPV antigen, focusing on only a few epitopes. Conversely, the T cells derived from peripheral blood recognized a broader range of HPV antigens. The characteristics of the HPV-specific cellular immunity that we have shown in these patients may be indicative of a failure to mount an effective response against the virus. This would be consistent with the chronic nature of the disease in these specific individuals. These observations could be relevant to the design and immunomonitoring of immunotherapeutic vaccines for persistent HPV infections.

Protective cell-mediated immunity by DNA vaccination against Papillomavirus L1 capsid protein in the Cottontail Rabbit Papillomavirus model

Papillomavirus major capsid protein L1 has successfully stimulated protective immunity against virus infection by induction of neutralizing antibodies in animal models and in clinical trials. However, the potential impact of L1-induced protective cell-mediated immune (CMI) responses is difficult to measure in vivo because of the coincidence of anti-L1 antibody. In this study, we tested the hypothesis that L1 could activate CMI, using the Cottontail Rabbit Papillomavirus (CRPV)-rabbit model. A unique property of this model is that infections can be initiated with viral DNA, thus bypassing all contributions to protection via neutralizing anti-L1 antibody. DNA vaccines containing either CRPV L1, or subfragments of L1 (amino-terminal two-thirds of L1 [L1N] and the carboxylterminal two-thirds of L1 [L1C]), were delivered intracutaneously into rabbits, using a gene gun. After three booster immunizations, the rabbits were challenged with several viral DNA constructs: wild-type CRPV, CRPV L1ATGko (an L1 ATG knockout mutation), and CRPV-ROPV hybrid (CRPV with a replacement L1 from Rabbit Oral Papillomavirus). Challenge of L1 DNA-vaccinated rabbits with wild-type CRPV resulted in significantly fewer papillomas when compared with challenge with CRPV L1ATGko DNA. Significantly smaller papillomas were found in CRPV L1-, L1N-, and L1C-vaccinated rabbits. In addition, rabbits vaccinated with either L1 or L1N grew significantly fewer and smaller papillomas when challenged with CRPV-ROPV hybrid DNA. Therefore, CRPV L1 DNA vaccination induced CMI responses to CRPV DNA infections that can contribute to protective immunity. Cross-protective immunity against CRPV L1 and ROPV L1 was elicited in these CRPV L1- and subfragment-vaccinated rabbits.

Immunohistochemical analysis of CD4+ and CD8+ T-cell subsets in high risk human papillomavirus-associated pre-malignant and malignant lesions of the uterine cervix

OBJECTIVES

Humoral and cellular immune responses are likely to play a key role for the clearance or persistence and progression of high risk (HR) HPV-associated cervical lesions. Although there are many studies describing the systemic T-cell responses to HPV16 and 18 proteins, few data are available regarding the cellular mucosal immune responses. We used immunohistochemistry to characterize populations of T-immune cells (CD4+, CD8+, CD45RO+) in HR-HPV-infected precancerous and cancerous lesions of the uterine cervix.

METHODS

Four biopsies from normal cervix, 9 CIN1 which have regressed (rCIN), 5 CIN1 which have progressed (pCIN) to high grade lesions, 13 CIN3 and 11 invasive carcinomas were included. All dysplasias and carcinomas were HR-HPV-positive and low-risk-HPV-negative. They were stained with monoclonal antibodies specific for CD4, CD8 and CD45RO and examined by microscopy.

STATISTICAL ANALYSIS

The Kruskal-Wallis test and the Siegel's and Castelan's method were used. RESULTS.: CD4+ cells predominated in regressing CIN1 both within the stroma and the epithelium with the highest CD4+/CD8+ ratio compared with pCIN1, CIN3 and invasive carcinoma. At the exception of CD45RO+ cells, T cells were detected with similar frequencies in both pCIN1 and CIN3. However, in 7 out of 10 CIN3, CD4+ and CD8+ cells were visible as organized lymphoid follicle structure. The CD8+ and CD45RO+ cells far exceeded the CD4+ cells in invasive cancers.

CONCLUSIONS

Density and distribution of immune T cells depend on the malignant potential of HR-HPV lesions. These results suggest that the studied lymphocyte subsets have an important role to fulfil during the natural history of HR-HPV-associated lesions.

Strategies for the prevention of cervical cancer by human papillomavirus vaccination

As cervical cancer is causally associated with 14 high-risk types of human papillomavirus (HPV), a successful HPV vaccine will have a major impact on this disease. Although some persistent HPV infections progress to cervical cancer, host immunity is generally able to clear most HPV infections. Both cell-mediated and antibody responses have been implicated in influencing the susceptibility, persistence or clearance of genital HPV infection. There have been two clinical trials that show that vaccines based on virus-like particles (VLPs) made from the major capsid protein, L1, are able to type specifically protect against cervical intra-epithelial neoplasia and infection. However, there is no evidence that even a mixed VLP vaccine will protect against types not included in the vaccine, and a major challenge that remains is how to engineer protection across a broader spectrum of viruses. Strategies for production of HPV vaccines using different vaccine vectors and different production systems are also reviewed.

Vaccination Against Cervical Cancer: Hopes and Realities

Globally, carcinomas of the anogenital tract, in particular cervical cancer, remain some of the most common cancers in women, cervical cancer represents the second most frequent gynecological malignancy and the third leading cause of cancer-related death in women worldwide. The causal relationship between human papilomavirus (HPV) infection and anogenital cancer has prompted substantial interest in the development of both preventive and therapeutic vaccines against high-risk HPV types. In the past decade, several groups have shown encouraging results using experimental vaccination systems in animal models and these results have led to several current prophylactic and therapeutic vaccine clinical trials in humans. Prophylactic vaccination focuses on the induction of high titer neutralizing antibodies that are potentially protective against incident and persistent HPV infection. Two major phase II clinical trials conducted by pharmaceutical companies have demonstrated that their vaccines have 100% efficacy in preventing persistent viral DNA and its associated cellular abnormalities; however, whether they induce long-lasting protective immunity is yet to be determined. At least one US FDA approved prophylactic vaccine targeting the two most common high-risk HPVs is expected to be on the market within the next 2-3 years. Nevertheless, significant reductions in the frequency and onset of cytologic screening and incidences of HPV-related lesions are not expected to become apparent for decades due to the fact that there will be women who are already infected with HPV, the long latency period between infection and development of high-grade lesions, and lesions associated with other high-risk HPV types not being included in the vaccines. Therapeutic vaccines aim to control HPV-associated malignancies by stimulating cellular immune responses that target established HPV infections via viral proteins. Progress in the field of HPV immunotherapy has remained elusive, with clinical trials being limited to small numbers of patients. Potential treatment of precancerous lesions is unique to HPV-associated infection and cancer because of cytologic monitoring and HPV typing. Unlike more common surgical treatments for cervical lesions, active immunotherapy has the potential to address HPV persistence as the cause of lesion development in addition to leaving the patient with long-term immunity that can be reactivated if and when the patient becomes reinfected.

Repetitive and consistent cervicovaginal exposure to certain viral pathogens appears to protect against their sexual acquisition in some women: potential mechanisms

Several groups have proposed that human female promiscuity or polyandry, with repetitive and consistent cervicovaginal exposure to human immunodeficiency virus type 1 (HIV-1), can lead to protection against sexual acquisition of HIV-1 in some of these women. The mechanism of this phenomenon, the highly exposed persistently HIV-seronegative (HEPS) state, is unknown. Thus far, it has been correlated with viral epitope-specific immune responses in only about half of the women evaluated. But when present, these responses decline rapidly following interruption of pathogen exposure, and correlate with prompt acquisition of HIV. I have extended the concept of HEPS to another sexually transmitted viral pathogen, human papillomavirus (HPV). Supporting clinical and immunological information were identified from a literature search using PubMed as well as several sets of epidemiological data, including longitudinal surveys of HIV-1 incidence among female commercial sex workers (CSWs) in Africa and Thailand, and follow-up of a Danish cohort of CSWs and a large group of Brazilian women, both at high risk for HPV infection. These studies suggest that male-to-female penile-vaginal transmission of at least two viruses, HIV-1 and HPV, is blocked by local mucosal responses, immunologic or otherwise, which require repetitive, uninterrupted exposure to pathogen. Exploration of the mechanisms underlying such ostensibly protective responses may facilitate development of STD vaccines.

Distinct T cell subsets and cytokine production in cultures derived from transformation zone and squamous intraepithelial lesion biopsies of the uterine cervix

PROBLEM

The characterization of lymphocytes issued from squamous intraepithelial lesions (SIL) and from the transformation zone (TZ), where the majority of SIL occur, is important to understand the role of immunity in SIL development.

METHOD OF STUDY

We compared lymphocyte populations of the TZ and SIL with those of normal exocervix, using a technique allowing for the isolation of lymphocytes, either from the epithelium or from the underlying stroma of small biopsies.

RESULTS

The majority of cells derived from the epithelium of all biopsies were CD8+ T cells. Some SIL-derived cultures were characterized by an increased proportion of activated TCRgammadelta+. The production of the immunosuppressive cytokine IL10 was significantly higher in lymphocyte cultures from the normal TZ in comparison with the exocervix. A decreased percentage of effector T cells was observed in cultures derived from the stroma of normal TZ (TCRgammadelta+) or SIL (CD8+) in comparison with the exocervix.

CONCLUSIONS

Our results suggest that a low proportion of effector T cells and IL10 production could contribute to the predisposition of the TZ to the development of SIL and to the progression of SIL to cervical cancer.

External genital warts: diagnosis, treatment, and prevention

External genital warts (EGWs) are visible warts that occur in the perigenital and perianal regions. They are due primarily to non-oncogenic human papillomavirus (HPV) types, usually types 6 and 11. Physical examination assisted by bright light and magnification is the recommended approach for primary diagnosis. Biopsy is indicated when EGWs are fixed to underlying structures or discolored or when standard therapies are not effective. Recurrences are common, and there is no single treatment that is superior to others. Among women with atypical squamous cells, molecular HPV testing may be useful in determining who should be referred for colposcopy. Condoms may provide some protection against HPV-related diseases and thus are recommended in new sexual relationships and when partnerships are not mutually monogamous. Because the efficacy of cesarean section in preventing vertical transmission of HPV infection from women with EGWs to their progeny has not been proved, it is not recommended.

Priming of human papillomavirus type 11-specific humoral and cellular immune responses in college-aged women with a virus-like particle vaccine

In this study, we evaluated the potency of a human papillomavirus (HPV) virus-like particle (VLP)-based vaccine at generating HPV type 11 (HPV-11)-specific cellular and humoral immune responses in seronegative women. The vaccine was administered by intramuscular immunizations at months 0, 2, and 6. A fourth immunization was administered to approximately half of the women at month 12. All vaccine recipients had positive HPV-11 VLP-specific lymphoproliferative responses at month 3 following the second immunization (geometric mean lymphoproliferative stimulation index [SI] = 28.4; 95% confidence interval [CI] = 16.9 to 48.0) and HPV-11 VLP-specific antibody titers following the first immunization at month 1 (geometric mean antibody titer = 53.9 milli-Merck units/ml, 95% CI, 34.8 to 83.7). In contrast, lymphoproliferative and antibody titer responses were never detected in the participants who received placebo. Relatively homogeneous lymphoproliferative responses were observed in all vaccinated women. The mean lymphoproliferative SI of the vaccinated group over the first 12 months of the study was 7.6-fold greater than that of the placebo group following the initial immunization. The cellular immune responses generated by VLP immunization were both Th1 and Th2, since peripheral blood mononuclear cells from vaccinees, but not placebo recipients, secreted interleukin 2 (IL-2), IL-5, and gamma interferon (IFN-gamma) in response to in vitro stimulation with HPV-11 VLP. The proliferation-based SI was moderately correlated with IFN-gamma production and significantly correlated with IL-2 production after the third immunization (P = 0.078 and 0.002, respectively). The robust lymphoproliferative responses were specific for HPV-11, since SIs generated against bovine papillomavirus and HPV-16 VLPs were not generally observed and when detected were similar pre- and postimmunization.

Analysis of CD4(+) T-cell responses to human papillomavirus (HPV) type 11 L1 in healthy adults reveals a high degree of responsiveness and cross-reactivity with other HPV types

Human papillomavirus type 11 (HPV-11) infection causes genital warts and recurrent respiratory papillomatosis. While there is compelling evidence that CD4(+) T cells play an important role in immune surveillance of HPV-associated diseases, little is known about human CD4(+) T-cell recognition of HPV-11. We have investigated the CD4(+) T-cell responses of 25 unrelated healthy donors to HPV-11 L1 virus-like particles (VLP). CD4(+) T-cell lines from 21 of 25 donors were established. Cell sorting experiments carried out on cells from six donors demonstrated that the response was located in the CD45RA(low) CD45RO(high) memory T-cell population. To determine the peptide specificity of these responses, epitope selection was analyzed by using 95 15-mer peptides spanning the entire HPV-11 L1 protein. No single region of L1 was immunodominant; responders recognized between 1 and 10 peptides, located throughout the protein, and peptide responses fell into clear HLA class II restricted patterns. Panels of L1 peptides specific for skin and genital HPV were used to show that the L1 CD4(+) T-cell responses were cross-reactive. The degree of cross-reactivity was inversely related to the degree of L1 sequence diversity between these viruses. Finally, responses to HPV-11 L1 peptides were elicited from ex vivo CD45RO(+) peripheral blood mononuclear cells, demonstrating that recognition of HPV-11 was a specific memory response and not due to in vitro selection during tissue culture. This is the first study of CD4(+) T-cell responses to HPV-11 in healthy subjects and demonstrates marked cross-reactivity with other skin and genital HPV types. This cross-reactivity may be of significance for vaccine strategies against HPV-associated clinical diseases.

Immunology of human papillomavirus infection in lower genital tract neoplasia

Despite its being a relatively common virus, the study of human papillomavirus infection has lagged behind that of other viruses. Human papillomaviruses do not provoke strong systemic antibody or T-cell responses. Furthermore, the majority of those infected do not display clinical symptoms and are able to clear the virus by unknown mechanisms. In the last decade, however, research into human papillomavirus immunology has blossomed, for two main reasons. First, there is strong circumstantial evidence that the immune system can control papillomavirus infection, since the prevalence of human papillomavirus-associated neoplasia is increased in immunocompromised individuals. Second, the strong association between human papillomavirus infection and cervical cancer has led to attempts to develop prophylactic or therapeutic vaccines. In this chapter, our current knowledge of human papillomavirus immune responses will be reviewed, and how this relates to clinical practice will be discussed.

Intrahepatic genetic inoculation of hepatitis C virus RNA confers cross-protective immunity

Naturally occurring hepatitis C virus (HCV) infection has long been thought to induce a weak immunity which is insufficient to protect an individual from subsequent infections and has cast doubt on the ability to develop effective vaccines. A series of intrahepatic genetic inoculations (IHGI) with type 1a HCV RNA were performed in a chimpanzee to determine whether a form of genetic immunization might stimulate protective immunity. We demonstrate that the chimpanzee not only developed protective immunity to the homologous type 1a RNA after rechallenge by IHGI but was also protected from chronic HCV infection after sequential rechallenge with 100 50% chimpanzee infectious doses of a heterologous type 1a (H77) and 1b (HC-J4) whole-virus inoculum. These results offer encouragement to pursue the development of HCV vaccines.

Characterization of hepatitis C virus core-specific immune responses primed in rhesus macaques by a nonclassical ISCOM vaccine

Current therapies for the treatment of hepatitis C virus (HCV) infection are only effective in a restricted number of patients. Cellular immune responses, particularly those mediated by CD8(+) CTLs, are thought to play a role in the control of infection and the response to antiviral therapies. Because the Core protein is the most conserved HCV protein among genotypes, we evaluated the ability of a Core prototype vaccine to prime cellular immune responses in rhesus macaques. Since there are serious concerns about using a genetic vaccine encoding for Core, this vaccine was a nonclassical ISCOM formulation in which the Core protein was adsorbed onto (not entrapped within) the ISCOMATRIX, resulting in approximately 1-microm particulates (as opposed to 40 nm for classical ISCOM formulations). We report that this Core-ISCOM prototype vaccine primed strong CD4(+) and CD8(+) T cell responses. Using intracellular staining for cytokines, we show that in immunized animals 0.30-0.71 and 0.32-2.21% of the circulating CD8(+) and CD4(+) T cells, respectively, were specific for naturally processed HCV Core peptides. Furthermore, this vaccine elicited a Th0-type response and induced a high titer of Abs against Core and long-lived cellular immune responses. Finally, we provide evidence that Core-ISCOM could serve as an adjuvant for the HCV envelope protein E1E2. Thus, these data provide evidence that Core-ISCOM is effective at inducing cellular and humoral immune responses in nonhuman primates.

Natural HPV immunity and vaccination strategies

BACKGROUND

the task of preventing premature death in women may be delivered by vaccinating against the high-risk papillomaviruses associated with various malignancies.

OBJECTIVES

we will discuss the immune mechanisms likely to be relevant to the control of an HPV infection in the cervix and assess the limited evidence for such immune recognition in the natural history of infection.

CONCLUSION

the next generation of vaccination strategies should include the use of HPV 16 early (E2 and/or E6 and/or E7) and late gene targets (L1 and L2) expressed as VLPs with their clinical and immunological evaluation aimed at therapy as well as prophylaxis. Important clinical efficacy assessment may be deliverable in relatively short-term studies by targeting patients with HPV 16 associated vulval intraepithelial neoplasia.

The immunology of animal papillomaviruses

Papillomaviruses are species- and tissue-specific double-stranded DNA viruses. These viruses cause epithelial tumours in many animals, including man. Typically, the benign warts undergo spontaneous, immune-mediated regression, most likely effected by T-cells (especially CD4, but also CD8 subsets), whereas humoral immunity can prevent new infections. Some papillomavirus infections fail to regress spontaneously and others progress to malignant epithelial tumours. Additionally, the impact of these lesions is greater in immunosuppressed individuals. Many therapies are ineffective, and there is much interest in the potential for immunological intervention in papillomavirus infections of man and animals. Vaccination can be achieved with 'live' virus, formalin-inactivated virus, synthetic virus-like particles, and DNA vaccination. There has been much recent progress in the development of such vaccines for papillomavirus infections in the rabbit, ox and dog. Success in these animal models suggests that similar approaches may prove useful for prophylactic or therapeutic vaccination against the important human papillomaviruses involved in the development of cutaneous and anogenital warts, laryngeal papillomatosis, and cervical cancer.

Human papillomavirus vaccines

Genital human papillomavirus (HPV) infections are the viral sexually transmitted diseases most frequently diagnosed that include anogenital condylomas and squamous intra-$bepithelial lesions, among which the precursors of invasive carcinomas of the uterine cervix. In animal PV models, vaccination against L1 and/or L2 viral capsid proteins provides an efficient protection against infection, involving virus type-specific neutralizing antibodies. Vaccination against non-structural E1, E2, E6 or E7 viral proteins does not prevent infection, unless administered altogether, but tends to stimulate regression, warranting the design of therapeutic vaccines. Prophylactic vaccines based on the use of virus-like particles (VLPs) obtained by auto-assembly of L1 or L1 and L2 proteins produced by recombinant DNA technology are under phase I/II clinical trials for HPV6/11 associated with condylomas and for HPV16, the most frequent oncogenic genotype. Second generation vaccines are chimeric proteins or VLPs incorporating one of the structural proteins (L1 or L2) fused to a non-structural protein (E6, E7 or E2), which should induce both humoral and cellular immunity. Vaccine valency (number of genotypes), route of administration (humoral versus local immunity), vaccinees (children, young adults, gender) and forms of vaccines (recombinant $LSalmonella typhimurium*I$L, edible plants expressing L1 and L2 proteins, DNA vaccines, synthetic antigenic peptides) are under study. End points to evaluate vaccine efficacy in phase III trials should include viral DNA detection and typing, and screening for low or high grade intraepithelial lesions. Therapeutic vaccines based on recombinant HPV E6 and/or E7 vaccinia virus, L2-E7 fusion proteins or E7 peptides corresponding to cytotoxic T cell epitopes are currently tested (phase I/II trials) in patients with cervical carcinomas of advanced clinical stages or high grade intraepithelial lesions. Animal studies, phase I/II clinical trials and implementation of the community support that HPV vaccines will constitute an efficient means to prevent carcinoma of the uterine cervix.

Recurrent respiratory papillomatosis: altered CD8(+) T-cell subsets and T(H)1/T(H)2 cytokine imbalance

Human papillomaviruses (HPVs) cause benign papillomas and squamous cell carcinomas in the genital and respiratory tracts. Recurrent respiratory papillomas (RRP) generate a high level of morbidity and significant mortality because of their location, resistance to treatment, and relentless recurrence that can vary in frequency in a given patient and between patients. We have found that T-cells from these patients, when exposed to or isolated from autologous papilloma tissue, have an elevated percentage of CD8(+), CD28(-) T-cells, and that T-cells from many of these patients express an increase in T(H)2-like cytokine mRNA in response to autologous papilloma tissue. Furthermore, both of these immunologic findings correlate with disease severity. These observations suggest that patients with RRP, and possibly others with refractory HPV-induced lesions, are unable to manage their disease with an appropriate and effective HPV-specific, T-cell response. This immune imbalance may be responsible for the development and severity of HPV-induced respiratory papillomatosis.