Viral particles (VPs) have evolved so as to efficiently enter target cells and to deliver their genetic material. The current state of knowledge allows us to use VPs in the field of biomedicine as nanoparticles that are safe, easy to manipulate, inherently biocompatible, biodegradable, and capable of transporting various cargoes into specific cells. Despite the fact that these virus-based nanoparticles constitute the most common vectors used in clinical practice, the need remains for further improvement in this area. The aim of this review is to discuss the potential for enhancing the efficiency and versatility of VPs via their functionalization with cell-penetrating peptides (CPPs), short peptides that are able to translocate across cellular membranes and to transport various substances with them. The review provides and describes various examples of and means of exploitation of CPPs in order to enhance the delivery of VPs into permissive cells and/or to allow them to enter a broad range of cell types. Moreover, it is possible that CPPs are capable of changing the immunogenic properties of VPs, which could lead to an improvement in their clinical application. The review also discusses strategies aimed at the modification of VPs by CPPs so as to create a useful cargo delivery tool.

Background/Aim: The incidence of oropharyngeal tumours induced by human papillomaviruses (HPV) is ever increasing. Information about oral HPV prevalence and its risk factors are very important for future screening and early diagnosis of the disease. The present study aimed to assess oral HPV prevalence in healthy population and risk factors for HPV infection, since this data is scarce or even missing in Central Europe. Patients and Methods: HPV prevalence in oral rinse and HPV-specific antibodies in peripheral blood were investigated in two groups of healthy participants. Group I consisted of 294 students who reached sexual maturity after the HPV vaccine had been licensed with mean age 23.2 years, and Group II of 215 unvaccinated participants with the mean age 55.7 years. Additionally, the risk factors were evaluated. Results: In Group I, 2% of participants were positive for oral HPV DNA. A statistically significantly higher rate (8.8%) was found in Group II. The seropositivity rates for anamnestic HPV antibodies were comparable in both groups. None of the analysed risk factors was significantly associated with oral HPV positivity. Conclusion: The lower prevalence of oral HPV DNA in younger participants suggests the positive influence of vaccination against oral HPV.Human papillomaviruses (HPV) comprise a heterogeneous group with more than 200 genotypes classified into five genera. Alpha-PVs cause most HPV-associated mucosal lesions, both malignant and benign, while cutaneous beta-PV infections are common but mostly asymptomatic in immunocompetent patients. Alpha-PVs are categorized into low-risk (LR), which are involved in genital warts, premalignant lesions, and laryngeal papillomatosis, and highrisk (HR), including those associated with cervical, vaginal, penile, anal, and head and neck tumours. HPV16 is the most prevalent type found in cervical cancer cells and in all other malignancies associated with papillomaviruses (1).The increasing incidence of oropharyngeal cancer in developed countries has been accompanied by an increasing number of patients with HPV-associated tumours (2, 3). HR HPV-associated head and neck cancers have been shown to occur in younger patients, who lack the common risk factors of alcohol and tobacco use, and moreover, have been associated with a better prognosis (2, 4).Oral HPV prevalence in healthy individuals has been investigated in a number of studies. Comparable results have been reported on different continents, but only limited data is available from Europe (5). A review by Kreimer et al. on oral HPV prevalence in the US population included 18 studies with 4,581 healthy adults; it showed a prevalence of 4.5% for HPV, 3.5% for HR HPV, and 1.3% for HPV16 (6). A review based on 29 studies of Asian populations (22,756 individuals) has shown a comparable HPV prevalence of 5.5%, with 2.7% of HR HPV and 1.0% of HPV16 (7).The most common route of HPV transmission is sexual. Oral infection most likely occurs through intimate contact. Several studies have found that sexual behaviour (8-1...

Protein corona formation has been regarded as an obstacle to developing diagnostic and therapeutic nanoparticles for in vivo applications. Serum proteins that assemble around nanoparticles can hinder their targeting efficiency. Virus-based nanoparticles should be naturally predisposed to evade such barriers in host organisms. Here, we demonstrate that virus-like particles derived from mouse polyomavirus do not form a rich protein corona. These particles can be efficiently targeted to cells that overproduce transferrin receptors, e.g., cancer cells, by conjugating transferrin to the particle surface. In this study, we provide evidence that the interaction of virus-like particles with their newly assigned target receptor is not obstructed by serum proteins. The particles enter target cells via a clathrin-dependent endocytic pathway that is not naturally used by the virus. Our results support the notion that the natural properties of virus-like particles make them well-suited for development of nanosized theranostic tools resistant to detargeting by protein coronas.

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Active infection with BK polyomavirus (BKPyV) may cause serious complications in transplantation settings. Recently, the level of BKPyV IgG seroreactivity in graft donors has been shown to predict viremia and BKPyV‐associated nephropathy in kidney transplant (KTx) recipients. Pretransplantation testing of the donor and recipient BKPyV serostatus could, therefore, identify patients at high risk. For the development of serological immunoassays, antibody response to the predominant BKPyV subtypes (BKPyV‐I and BKPyV‐IV) was studied using virus‐like particle (VLP)‐based enzyme‐linked immunosorbent assay (ELISA). VLPs made from the capsid protein, VP1, derived from BKPyV‐I and BKPyV‐IV subtypes were produced using a baculovirus expression system and used as antigens. The tests were used for IgG antibody determination in 50 KTx recipients and 111 healthy blood donors. While 87% of samples reacted with mixed BKPyV‐I and BKPyV‐IV antigens, only 49% of samples were reactive in both ELISA tests when using BKPyV‐I or BKPyV‐IV antigens separately. Twenty‐seven percent of healthy blood donors and 26% of KTx recipients were reactive only with BKPyV‐I, while 9% and 20% were reactive only with BKPyV‐IV, respectively. To determine the specificities of the antigens, selected seropositive samples were retested after preadsorption with soluble BKPyV‐I, BKPyV‐IV, or JC polyomavirus antigens. The experiments confirmed that recombinant VP1 VLP‐based ELISAs predominantly detected BKPyV type‐specific antibodies. The results imply that anti‐BKPyV antibody ELISA tests should contain a mixture of subtype‐specific VLP‐based antigens instead of antigen derived from the most prevalent BKPyV‐I subtype. The tests can be used for serological surveys of BKPyV infection and improved KTx patient management.