Modulation of antigen presenting cell functions during chronic HPV infection.

High-risk human papillomaviruses (HR-HPV) infect basal keratinocytes, where in some individuals they evade host immune responses and persist. Persistent HR-HPV infection of the cervix causes precancerous neoplasia that can eventuate in cervical cancer. Dendritic cells (DCs) are efficient in priming/cross-priming antigen-specific T cells and generating antiviral and antitumor cytotoxic CD8+ T cells. However, HR-HPV have adopted various immunosuppressive strategies, with modulation of DC function crucial to escape from the host adaptive immune response. HPV E6 and E7 oncoproteins alter recruitment and localization of epidermal DCs, while soluble regulatory factors derived from HPV-induced hyperplastic epithelium change DC development and influence initiation of specific cellular immune responses. This review focuses on current evidence for HR-HPV manipulation of antigen presentation in dendritic cells and escape from host immunity

HPV16 E7-driven epithelial hyperplasia promotes impaired antigen presentation and regulatory T cell development

Human papillomaviruses (HPV) infect keratinocytes and can lead to hyperproliferative dysplasia and malignant transformation if not cleared by the immune system. HPV has evolved an array of mechanisms to evade and manipulate the immune system to improve replication efficiency and promote persistent infection. We here demonstrate that hyperproliferative skin expressing the high-risk HPV16 E7 oncogene as a transgene drives immune-modulation of dendritic cells (DCs) resulting in reduced capacity to take up antigen and prime effector CD4 T cell responses. The phenotype of DCs in the E7-expressing hyperproliferative skin was not reversible by activation through intradermal immunization. Naïve CD4 T cells primed by E7-driven hyperproliferative skin acquired FoxP3 expression and an anergic phenotype. DC and T help modulation was dependent on E7-Rb interaction-driven epithelial hyperproliferation, rather than on expression of E7, as inhibition of binding of E7 to retinoblastoma protein, and of consequent epithelial hyperplasia was associated with normal skin DC phenotype, and Th1 effector responses to immunization were restored. We conclude that HPV-induced epithelial hyperplasia modulates epithelial DCs and inhibits Th1 immunity while polarizing T cell differentiation to a regulatory or anergic phenotype

Comparison of loop-mediated isothermal amplification assay and smear microscopy with culture for the diagnostic accuracy of tuberculosis

Published online: 17 January 2017Background: Tuberculosis (TB) caused by Mycobacterium tuberculosis is one of the leading causes of death from infectious diseases worldwide. Sputum smear microscopy remains the most widely available pulmonary TB diagnostic tool particularly in resource limited settings. A highly sensitive diagnostic with minimal infrastructure, cost and training is required. Hence, we assessed the diagnostic performance of Loop-mediated isothermal amplification (LAMP) assay in detecting M.tuberculosis infection in sputum sample compared to LED fluorescent smear microscopy and culture. Method: A cross-sectional study was conducted at the University of Gondar Hospital from June 01, 2015 to August 30, 2015. Pulmonary TB diagnosis using sputum LED fluorescence smear microscopy, TB-LAMP assay and culture were done. A descriptive analysis was used to determine demographic characteristics of the study participants. Analysis of sensitivity and specificity for smear microscopy and TB-LAMP compared with culture as a reference test was performed. Cohen’s kappa was calculated as a measure of agreement between the tests. Results: A total of 78 pulmonary presumptive TB patients sputum sample were analyzed. The overall sensitivity and specificity of LAMP were 75 and 98%, respectively. Among smear negative sputum samples, 33.3% sensitivity and 100% specificity of LAMP were observed. Smear microscopy showed 78.6% sensitivity and 98% specificity. LAMP and smear in series had sensitivity of 67.8% and specificity of 100%. LAMP and smear in parallel had sensitivity of 85.7% and specificity of 96%. The agreement between LAMP and fluorescent smear microscopy tests was very good (κ = 0.83, P-value ≤0.0001). Conclusions: TB-LAMP showed similar specificity but a slightly lower sensitivity with LED fluorescence microscopy. The specificity of LAMP and smear smear microscopy in series was high. The sensitivity of LAMP was insufficient for smear negative sputum samples.Baye Gelaw, Yitayal Shiferaw, Marta Alemayehu and Abate Assefa Basha

Prevalence of selected sexually transmitted infection (STI) and associated factors among symptomatic patients attending Gondar Town hospitals and health centers

BACKGROUND: Sexually transmitted infection (STI) is a major global cause of acute illness, infertility, long-term disability and death, with serious medical and psychological consequences to millions of men, women and infants. Moreover, in Ethiopia, epidemiological studies on STI among STI clinic clients are limited. Therefore, the aim of this study was to determine the prevalence and associated risk factors of sexually transmitted infection (STI).METHODS: A cross sectional study was conducted between April and August 2014 among STI clinic clients in Gondar Town hospitals and health centers. One hundred twenty study participants who fulfill the criteria were included. Different laboratory methods and techniques were applied to identify the possible microorganisms. Data were entered and analyzed using SPSS version 20. Logistic regression was used to determine risk factors for STI and P values < 0.05 was considered statistically significant.RESULTS: The overall laboratory test confirmed that STIs prevalence was 74.1% with 32.5% being Candida spp., 30% T. palladium, 20.8% N. gonorrhoeae and 14.2% T. vaginalis. Two or more organisms were isolated in 20% of the study subjects. Risk factors for STI had knowledge about STI and alcohol consumption.CONCLUSION: The prevalence of N. gonorrhoeae, T. pallidum, T. vaginalis, and Candida spp. in the study area was high. It needs health education programs, promotes condom utilization and more comprehensive community based STI studies

Regulatory T-cells but not IL-10 impair cell-mediated immunity in HPV+ hyperplastic epithelium

High-risk human papillomavirus (HPV) infection can induce cervical and other intraepithelial neoplasia and invasive cancers. A transgenic mouse expressing the HPV16 E7 oncoprotein driven by the K14 promotor (K14E7tg) exhibits epithelial hyperplasia and mimics many features of human HPV-related intraepithelial precancers. We have previously demonstrated that K14E7tg-mediated epithelial hyperplasia suppresses T helper type 1 (Th1) responses to intradermally delivered antigen and directs differentiation of CD4 T-cells towards a Foxp3 regulatory phenotype (Treg). Here we establish that Foxp3 Treg expansion from a transferred naïve T-cell population is driven directly by the hyperplastic skin and is independent of pre-existing immune-modulated lymphocytes. However, depletion of endogenous CD25 Tregs before priming of adoptively transferred T-cells significantly improves antigen specific CD8 T-cell responses, but not Th1 responses. Deletion of IL-10 had no effect on Treg expansion, epidermal dendritic cell alteration and suppression of induced Th1 immunity in K14E7tg mice. Thus, HPV16 E7-mediated epithelial hyperplasia promotes expansion of peripheral Tregs in response to intradermal immunisation which suppress antigen-specific CD8 T-cell responses independently of IL-10, but depletion of these Tregs is not sufficient to restore Th1 immunity