Probes for INS

Mus musculus Papillomavirus1 (MmuPV1/MusPV1) induces persistent papillomas in immunodeficient mice but not common laboratory strains. To facilitate study of immune control, we sought an outbred and immune competent laboratory mouse strain in which persistent papillomas could be established. We found that challenge of SKH1 mice (Crl:SKH1-Hrhr) by scarification on their tail with MmuPV1 resulted in three clinical outcomes: 1) persistent (>2 months) papillomas (∼20%), 2) transient papillomas that spontaneously regress typically within 2 months (∼15%), 3) no visible papillomas and viral clearance (∼65%). SKH1 mice with persistent papillomas were treated using a candidate preventive/therapeutic naked DNA vaccine that expresses human calreticulin (hCRT) fused in frame to MmuPV1 E6 (mE6) and E7 (mE7) early proteins and residues 11-200 of late protein L2 (hCRTmE6/mE7/mL2). Three intramuscular DNA vaccinations were delivered biweekly via in vivo electroporation, and both humoral and CD8 T cell responses were mapped and measured. Previously persistent papillomas disappeared within 2 months after the final vaccination. Coincident virologic clearance was confirmed by in situ hybridization and failure of disease to recur after CD3 T cell depletion. Vaccination induced a strong mE6 and mE7 CD8+ T cell response in all mice, although significantly lower in mice that initially presented with persistent warts as compared with those that spontaneously cleared their infection. An HPV16-targeted version of the DNA vaccine also induced L2 antibodies and protected mice from vaginal challenge with HPV16 pseudovirus. Thus MmuPV1 challenge of SKH1 mice is a promising model of spontaneous and immunotherapy-directed clearance of HPV-related disease.IMPORTANCE High risk type human papillomaviruses (hrHPV) cause 5% of all cancer cases worldwide, notably cervical, anogenital and oropharyngeal cancers. Since preventative HPV vaccines have not been widely used in many countries, and do not impact existing infections, there is considerable interest in the development of therapeutic vaccines to address existing disease and infections. The strict tropism of HPV requires the use of animal papillomavirus models for therapeutic vaccine development. However, MmuPV1 failed to grow in common laboratory strains of mice with an intact immune system. We show that MmuPV1 challenge of the outbred immunocompetent SKH1 strain produces both transient and persistent papillomas, and that vaccination of the mice with a DNA expressing an MmuPV1 E6E7L2 fusion with calreticulin can rapidly clear persistent papillomas. Further an HPV16-targeted version of the DNA can protect against vaginal challenge with HPV16 suggesting the promise of this approach to both prevent and treat papillomavirus-related disease.

BACKGROUND:

Enteroviruses (EVs) have been linked to the pathogenesis of several diseases and there is a collective need to develop improved methods for the detection of these viruses in tissue samples.

OBJECTIVES:

This study evaluates the relative sensitivity of immunohistochemistry (IHC), proteomics, in situ hybridization (ISH) and RT-PCR to detect one common EV, Coxsackievirus B1 (CVB1), in acutely infected human A549 cells in vitro.

STUDY DESIGN:

A549 cells were infected with CVB1 and diluted with uninfected A549 cells to produce a limited dilution series in which the proportion of infected cells ranged from 10-1 to 10-8. Analyses were carried out by several laboratories using IHC with different anti-EV antibodies, ISH with both ViewRNA and RNAScope systems, liquid chromatography multiple reaction monitoring mass spectrometry (LC/MRM/MS/MS), and two modifications of RT-PCR.

RESULTS:

RT-PCR was the most sensitive method for EV detection yielding positive signals in the most diluted sample (10-8). LC/MRM/MS/MS detected viral peptides at dilutions as high as 10-7. The sensitivity of IHC depended on the antibody used, and the most sensitive antibody (Dako clone 5D8/1) detected virus proteins at a dilution of 10-6, while ISH detected the virus at dilutions of 10-4.

CONCLUSIONS:

All methods were able to detect CVB1 in infected A549 cells. RT-PCR was most sensitive followed by LC/MRM/MS/MS and then IHC. The results from this in vitro survey suggest that all methods are suitable tools for EV detection but that their differential sensitivities need to be considered when interpreting the results from such studies.

OBJECTIVE:

Resting CD4+ T cells have been recognized as the major cell reservoir of latent HIV-1 during antiretroviral therapy (ART). Using an SIV/macaque model for AIDS and HIV-related neurocognitive disorders we assessed the contribution of the brain to viral latency and reactivation.

DESIGN:

Pigtailed macaques were dual inoculated with SIVDeltaB670 and SIV17E-Fr and treated with an efficacious CNS-penetrant ART. After 500 days of viral suppression animals were treated with two cycles of latency reversing agents (LRAs) and increases in viral transcripts were examined.

METHODS:

Longitudinal plasma and CSF viral loads were analyzed by quantitative and digital droplet PCR. After necropsy, viral transcripts in organs were analyzed by PCR, in situ hybridization (ISH), and phylogenetic genotyping based on env V1 loop sequences. Markers for neuronal damage and CSF activation were measured by ELISA.

RESULTS:

Increases in activation markers and plasma and CSF viral loads were observed in one animal treated with LRAs, despite ongoing ART. SIV transcripts were identified in occipital cortex macrophages by ISH and CD68+ staining. The most abundant SIV genotype in CSF was unique and expanded independent from viruses found in the periphery.

CONCLUSION:

The CNS harbors latent SIV genomes after long-term viral suppression by ART indicating that the brain represents a potential viral reservoir and should be seriously considered during AIDS cure strategies.

OBJECTIVE:

The stability of the covalently closed circular DNA (cccDNA) in nuclei of non-dividing hepatocytes represents a key determinant of HBV persistence. Contrarily, studies with animal hepadnaviruses indicated that hepatocyte turnover can reduce cccDNA loads but knowledge on the proliferative capacity of HBV-infected primary human hepatocytes (PHHs) in vivo and the fate of cccDNA in dividing PHHs is still lacking. This study aimed to determine the impact of human hepatocyte division on cccDNA stability in vivo.

METHODS:

PHH proliferation was triggered by serially transplanting hepatocytes from HBV-infected humanised mice into naïve recipients. Cell proliferation and virological changes were assessed by quantitative PCR, immunofluorescence and RNA in situ hybridisation. Viral integrations were analysed by gel separation and deep sequencing.

RESULTS:

PHH proliferation strongly reduced all infection markers, including cccDNA (median 2.4 log/PHH). Remarkably, cell division appeared to cause cccDNA dilution among daughter cells and intrahepatic cccDNA loss. Nevertheless, HBV survived in sporadic non-proliferating human hepatocytes, so that virological markers rebounded as hepatocyte expansion relented. This was due to reinfection of quiescent PHHs since treatment with the entry inhibitor myrcludex-B or nucleoside analogues blocked viral spread and intrahepatic cccDNA accumulation. Viral integrations were detected both in donors and recipient mice but did not appear to contribute to antigen production.

CONCLUSIONS:

We demonstrate that human hepatocyte division even without involvement of cytolytic mechanisms triggers substantial cccDNA loss. This process may be fundamental to resolve self-limiting acute infection and should be considered in future therapeutic interventions along with entry inhibition strategies.

BACKGROUND & AIMS:
Viral clearance involves immune cell cytolysis of infected cells. However, studies of hepatitis B virus (HBV) infection in chimpanzees have indicated that cytokines released by T cells also can promote viral clearance via noncytolytic processes. We investigated the noncytolytic mechanisms by which T cells eliminate HBV from infected hepatocytes.

METHODS:
We performed a cytokine enzyme-linked immunosorbent assay of serum samples from patients with acute and chronic hepatitis B. Liver biopsy specimens were analyzed by in situ hybridization. HepG2-H1.3 cells, HBV-infected HepaRG cells, and primary human hepatocytes were incubated with interferon-γ (IFNγ) or tumor necrosis factor-α (TNFα), or co-cultured with T cells. We measured markers of HBV replication, including the covalently closed circular DNA (cccDNA).

RESULTS:
Levels of IFNγ and TNF-α were increased in serum samples from patients with acute vs chronic hepatitis B and controls. In human hepatocytes with stably replicating HBV, as well as in HBV-infected primary human hepatocytes or HepaRG cells, IFNγ and TNF-α each induced deamination of cccDNA and interfered with its stability; their effects were additive. HBV-specific T cells, through secretion of IFNγ and TNF-α, inhibited HBV replication and reduced cccDNA in infected cells without the direct contact required for cytolysis. Blocking IFNγ and TNF-α after T-cell stimulation prevented the loss of cccDNA. Deprivation of cccDNA required activation of nuclear APOBEC3 deaminases by the cytokines. In liver biopsy specimens from patients with acute hepatitis B, but not chronic hepatitis B or controls, hepatocytes expressed APOBEC3A and APOBEC3B.

CONCLUSIONS:
IFNγ and TNF-α, produced by T cells, reduce levels of HBV cccDNA in hepatocytes by inducing deamination and subsequent cccDNA decay.