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Despite the clinical need of novel and safe anti-herpetic compounds effective for treating both primary infections and reactivations of Herpes Simplex Virus type 1 (HSV-1) and type 2 (HSV-2), the development of novel antivirals approved for clinical administration has been limited in the last decades to improvements of nucleoside analogues compounds. In this context, targeting different steps of the herpesvirus life cycle, including entry and cell-to-cell infection, can represent an important starting point for obtaining more efficient infection inhibition, and for overcoming both drug resistance and toxicity. Under these perspectives, testing possible synergy between drugs currently in clinical use and novel immunotherapeutics, such as neutralizing human monoclonal antibodies, represents a fascinating option. In the study here described we tested for the first-time possible combinations of inhibitors of Herpesvirus DNA synthesis and a human neutralizing IgG able to block also cell-to-cell infection, by analysing experimental results with different mathematical models. The present study clearly highlights the synergism between all anti-herpetic drugs tested in combination with the mAb; this strongly suggests possible reduction of anti-herpetic drugs combined with the IgG for overcoming drug-related side effects, as indicated by Drug Reduction Index., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The present study focused on inhibition of HSV-1 and -2 replication and pathogenesis in vitro and in vivo, through the selective targeting of the envelope glycoprotein D. Firstly, a human monoclonal antibody (Hu-mAb#33) was identified that could neutralise both HSV-1 and -2 at nM concentrations, including clinical isolates from patients affected by different clinical manifestations and featuring different susceptibility to acyclovir in vitro. Secondly, the potency of inhibition of both infection by cell-free viruses and cell-to-cell virus transmission was also assessed. Finally, mice receiving a single systemic injection of Hu-mAb#33 were protected from death and severe clinical manifestations following both ocular and vaginal HSV-1 and -2 lethal challenge. These results pave the way for further studies reassessing the importance of HSV entry as a novel target for therapeutic intervention and inhibition of cell-to-cell virus transmission., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Background: The cellular adaptive response directed against herpesviruses is widely described in the scientific literature as a pivotal component of the immune system able to control virus replication. The role of humoral immunity remains unclear and controversial., Aims: Discussing the role of adaptive immunity in herpesvirus infection control, highlighting the potential role of the humoral branch of immunity through the description of human monoclonal antibodies directed against herpesviruses., Sources: PubMed search for relevant publications related to protective immunity against Herpesviridae., Content: This review describes the role of adaptive immunity directed against Herpesviridae, focusing on the human humoral response naturally elicited during their infections. Given the ever-increasing interest in monoclonal antibodies as novel therapeutics, the contribution of humoral immunity in controlling productive infection, during both primary infection and reactivations, is discussed., Implications: Human monoclonal antibodies directed against the different Herpesviridae species may represent novel molecular probes to further characterize the molecular machinery involved in herpesvirus infection; and allow the development of novel therapeutics and effective vaccine strategies., (Copyright © 2017 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Bacteriophage therapy dates back almost a century, but the discovery of antibiotics led to a rapid decline in the interests and investments within this field of research. Recently, the novel threat of multidrug-resistant bacteria highlighted the alarming drop in research and development of new antibiotics: 16 molecules were discovered during 1983-87, 10 new therapeutics during the nineties, and only 5 between 2003 and 2007. Phages are therefore being reconsidered as alternative therapeutics. Phage display technique has proved to be extremely promising for the identification of effective antibodies directed against pathogens, as well as for vaccine development. At the same time, conventional phage therapy uses lytic bacteriophages for treatment of infections and recent clinical trials have shown great potential. Moreover, several other approaches have been developed in vitro and in vivo using phage-derived proteins as antibacterial agents. Finally, their use has also been widely considered for public health surveillance, as biosensor phages can be used to detect food and water contaminations and prevent bacterial epidemics. These novel approaches strongly promote the idea that phages and their proteins can be exploited as an effective weapon in the near future, especially in a world which is on the brink of a "postantibiotic era."

JC virus (JCPyV) has gained novel clinical importance as cause of progressive multifocal leukoencephalopathy (PML), a rare demyelinating disease recently associated to immunomodulatory drugs, such as natalizumab used in multiple sclerosis (MS) cases. Little is known about the mechanisms leading to PML, and this makes the need of PML risk stratification among natalizumab-treated patients very compelling. Clinical and laboratory-based risk-stratification markers have been proposed, one of these is represented by the JCPyV-seropositive status, which includes about 54% of MS patients. We recently proposed to investigate the possible protective role of neutralizing humoral immune response in preventing JCPyV reactivation. In this proof-of-concept study, by cloning the first human monoclonal antibody (GRE1) directed against a neutralizing epitope on JCPyV/VP1, we optimized a robust anti-JCPyV neutralization assay. This allowed us to evaluate the neutralizing activity in JCPyV-positive sera from MS patients, demonstrating the lack of correlation between the level of anti-JCPyV antibody and anti-JCPyV neutralizing activity. Relevant consequences may derive from future clinical studies induced by these findings; indeed the study of the serum anti-JCPyV neutralizing activity could allow not only a better risk stratification of the patients during natalizumab treatment, but also a better understanding of the pathophysiological mechanisms leading to PML, highlighting the contribution of peripheral versus central nervous system JCPyV reactivation. Noteworthy, the availability of GRE1 could allow the design of novel immunoprophylactic strategies during the immunomodulatory treatment., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease of the central nervous system (CNS), observed in immunodeficient patients and caused by JC virus ((JCV), also called JC polyomavirus (JCPyV)). After the HIV pandemic and the introduction of immunomodulatory therapy, the PML incidence significantly increased. The correlation between the use of natalizumab, a drug used in multiple sclerosis (MS), and the PML development of particular relevance. The high incidence of PML in natalizumab-treated patients has highlighted the importance of two factors: the need of PML risk stratification among natalizumab-treated patients and the need of effective therapeutic options. In this review, we discuss these two needs under the light of the major viral models of PML etiopathogenesis.

Broadly neutralizing monoclonal antibodies (mAbs) directed against different subtypes of influenza A viruses are novel tools for the potential development of effective anti-influenza prophylactic and therapeutic strategies. In both cases, the main candidates for passive transfer and new vaccine development are represented by protective mAbs directed against influenza hemagglutinin (HA). A large number of mAbs directed against influenza HA has been developed to date. However, even if they can be useful and contribute to develop new vaccinal strategies, only few of them can be a good candidate for human administration. In this review, we will describe the most relevant human mAb directed against influenza HA able to recognize highly divergent influenza isolates and possibly useful for human therapy and prophylaxis.