BK virus: microbiology, epidemiology, pathogenesis, clinical manifestations and treatment

Fecal, oral, blood and skin virome of laboratory rabbits

Here, we investigated the fecal, oral, blood, and skin virome of 10 laboratory rabbits using a viral metagenomic method. In the oral samples, we detected a novel polyomavirus (RabPyV), and phylogenetic analysis based on the large T antigen, VP1 and VP2 regions indicated that the novel strain might have undergone a recombination event. Recombination analysis based on related genomes confirmed that RabPyV is a multiple recombinant between rodent-like and avian-like polyomaviruses. In fecal samples, three partial or complete genome sequences of viruses belonging to the families Picobirnaviridae, Parvoviridae, Microviridae and Coronaviridae were characterized, and phylogenetic trees were constructed based on the predicted amino acid sequences of viral proteins. This study increases the amount of genetic information on viruses present in laboratory rabbits.

BK Polyomavirus: Clinical Aspects, Immune Regulation, and Emerging Therapies

BK polyomavirus (BKV) causes frequent infections during childhood and establishes persistent infections within renal tubular cells and the uroepithelium, with minimal clinical implications. However, reactivation of BKV in immunocompromised individuals following renal or hematopoietic stem cell transplantation may cause serious complications, including BKV-associated nephropathy (BKVAN), ureteric stenosis, or hemorrhagic cystitis. Implementation of more potent immunosuppression and increased posttransplant surveillance has resulted in a higher incidence of BKVAN. Antiviral immunity plays a crucial role in controlling BKV replication, and our increasing knowledge about host-virus interactions has led to the development of improved diagnostic tools and clinical management strategies. Currently, there are no effective antiviral agents for BKV infection, and the mainstay of managing reactivation is reduction of immunosuppression. Development of immune-based therapies to combat BKV may provide new and exciting opportunities for the successful treatment of BKV-associated complications.

BK polyomavirus: a review of the virology, pathogenesis, clinical and laboratory features, and treatment

BK polyomavirus (BKPyV) is a non-enveloped, circular dsDNA virus with a genome of approximately 5100 base pairs. It can be divided into four major genotypes, but the effects of different genotypes on clinical disease are uncertain. Primary BKPyV infection is generally acquired asymptomatically in childhood. It establishes low-level persistence in many tissues, particularly the genitourinary tract. Reactivation can lead to severe disease including BKPyV-associated nephropathy confirmed by renal biopsy, hemorrhagic cystitis and meningoencephalitis. Nucleic acid amplification testing of blood and urine is the main diagnostic and prognostic test for BKPyV infection. The treatment of BKPyV infection has concentrated on reduction in immunosuppressive therapy. Recent studies suggest that antiviral drugs have demonstrated only modest benefit, but adoptive T-cell therapies offer potential advances.

Reining in polyoma virus associated nephropathy: design and characterization of a template mimicking BK viral coat protein cellular binding

The BK polyoma virus is a leading cause of chronic post kidney transplantation rejection. One target for therapeutic intervention is the initial association of the BK virus with the host cell. We hypothesize that the rate of BKV infection can be curbed by competitively preventing viral binding to cells. The X-ray structures of homologous viruses complexed with N-terminal glycoproteins suggest that the BC and HI loops of the viral coat are determinant for binding and thereby infection of the host cell. The large size of the viral coat precludes it from common biophysical and small molecule screening studies. Hence, we sought to develop a smaller protein template incorporating the identified binding loops of the BK viral coat in a manner that adequately mimics the binding characteristics of the BK virus coat protein to cells. Such a mimic may serve as a tool for the identification of inhibitors of BK viral progression. Herein, we report the design and characterization of a reduced-size and soluble template derived from a four-helix protein-TM1526 of Thermatoga maritima archaea bacteria-which maintains the topological display of the BC and HI loops as found in the viral coat protein, VP1, of BKV. We demonstrate that the GT1b and GD1b sialogangliosides, which bind to the VP1 of BKV, also associate with our BKV template. Employing a GFP-tagged template, we show host cell association that is dose dependent and that can be reduced by neuraminidase treatment. These data demonstrate that the BKV template mimics the host cell binding observed for the wild-type virus coat protein VP1.