There are still many unanswered questions concerning viral SARS-CoV-2 pathogenesis in COVID-19. Accessory proteins in SARS-CoV-2 consist of eleven viral proteins whose roles during infection are still not completely understood. Here, a review on the current knowledge of SARS-CoV-2 accessory proteins is summarized updating new research that could be critical in understanding SARS-CoV-2 interaction with the host. Some accessory proteins such as ORF3b, ORF6, ORF7a and ORF8 have been shown to be important IFN-I antagonists inducing an impairment in the host immune response. In addition, ORF3a is involved in apoptosis whereas others like ORF9b and ORF9c interact with cellular organelles leading to suppression of the antiviral response in infected cells. However, possible roles of ORF7b and ORF10 are still awaiting to be described. Also, ORF3d has been reassigned. Relevant information on the knowns and the unknowns in these proteins is analyzed, which could be crucial for further understanding of SARS-CoV-2 pathogenesis and to design strategies counteracting their actions evading immune responses in COVID-19.

Monitoring of the Torque Teno virus (TTV) DNAemia, a non-pathogenic component of human virome, can be useful to assess the net state of immunosuppression among SOT recipients.

Virus infections can result in a variety of cellular injuries, and these often involve the permeabilization of host membranes by viral proteins of the viroporin family. Prototypical viroporin 2B is responsible for the alterations in host cell membrane permeability that take place in enterovirus-infected cells. 2B protein can be localized at the endoplasmic reticulum (ER) and the Golgi complex, inducing membrane remodeling and the blockade of glycoprotein trafficking. These findings suggest that 2B has the potential to integrate into the ER membrane, but specific information regarding its biogenesis and mechanism of membrane insertion is lacking. Here, we report experimental results of in vitro translation-glycosylation compatible with the transloconmediated insertion of the 2B product into the ER membrane as a double-spanning integral membrane protein with an N-/C-terminal cytoplasmic orientation. A similar topology was found when 2B was synthesized in cultured cells. In addition, the in vitro translation of several truncated versions of the 2B protein suggests that the two hydrophobic regions cooperate to insert into the ER-derived microsomal membranes.Virus infections can lead to a variety of cellular injuries, and usually these involve the restructuring of host membrane systems. Viroporins are a group of small virally encoded proteins that interact with cellular membranes to modify permeability and promote the release of viral particles. A typical feature exhibited by viroporins is the presence of at least one membrane-spanning helix anchoring the protein into membranes. After membrane insertion, their oligomerization creates hydrophilic channels or pores (22).Poliovirus is the enterovirus prototype member of the Picornaviridae family. This small, nonenveloped, icosahedral virus possesses a single-stranded 7.5-kb positive-sense RNA genome that encodes a single polyprotein. Polyprotein processing by virus-encoded proteases yields the structural P1 region proteins that encapsidate viral RNA and the nonstructural P2 and P3 region proteins involved in the replication of the viral RNA and membrane permeabilization (2). Nonstructural 2B protein is one of the products generated on processing the P2 region (62). Viroporin 2B has been identified as one of the viral proteins responsible for the alterations in host cell membrane permeability that take place in enterovirus-infected cells. Different 2B proteins expressed in cells have been localized at the endoplasmic reticulum (ER), Golgi complex, and, to a lesser extent, to the plasma and mitochondrial membranes (18,31,49,58). Biochemical and structural data indicate that viroporins form homo-oligomers that create pores in the ER and Golgi complex membranes (1,16,17,30,59). However, experimental data dealing with the mechanism of the membrane integration of the 2B product are lacking to date.The poliovirus 2B viroporin protein is hydrophobic overall and rather small (97 amino acids). Hydrophobicity within the viroporin 2B sequence seems to cluster in two main regions (F...