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HIV/AIDS
Published in Patricia G. Melloy, Viruses and Society, 2023
HIV has an envelope displaying spike proteins and contains two copies of its positive sense single-stranded RNA genome (Lostroh 2019; Cloyd 1996). To enter cells, HIV binds to the CD4 receptor on the surface of the T-helper cells as well as a chemokine co-receptor, such as CCR5, and then uses a fusion peptide to make an opening to enter the cell. Once the virus enters the cells, reverse transcription occurs, and the viral genome can move to the nucleus and integrate into the host cell genome using an enzyme known as an integrase. Other viral proteins are made using the host cell’s translational machinery, and then the viral protein chains are cleaved by a protease when the virus matures. Once the viral particle is assembled, it buds out of the host cell and moves onto another cell (Lostroh 2019; Minkoff and Baker 2004; Cloyd 1996; Walker 2008a) (Ackermann, Berthiaume, and Tremblay1998) (Figure 5.1).
Risk factors – Treatable traits
Published in Vibeke Backer, Peter G. Gibson, Ian D. Pavord, The Asthmas, 2023
Vibeke Backer, Peter G. Gibson, Ian D. Pavord
Respiratory viral infection is recognised by typical clinical manifestations of coryzhal symptoms and fever. This can be quantified using the common cold questionnaire. Infection is confirmed by detecting viral nucleic acid using PCR. Immunofluorescence methods can also be used to detect viral proteins and confirm infection. Suitable samples are nasopharyngeal swabs and sputum samples. Acute and convalescent serology can be used to detect an antibody response and is typically used in research settings or as part of epidemic/pandemic management. SARS-CoV-2 is a novel coronavirus that causes COVID-19 illness and the current pandemic (2020). It can be diagnosed using PCR testing of nasopharyngeal secretions or acute and convalescent serology.
The Viruses
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
Viruses have no intrinsic means to generate energy so they must rely totally on the metabolic machinery of host cells to synthesize new viral components. During viral replication, the nucleic acid of the virus which composes its genome becomes active within the infected cell and serves as a template to make copies of itself and to produce new viral proteins. These newly synthesized proteins and genomic elements assemble into new infectious virions that are released by cell lysis or by budding from the host cell. In some cases the viral genome may incorporate into the host cell DNA leading to persistent infections that may lead to many changes in the host cell including cancer. The genetic information in the virus genome and in the host cell determines the outcome of the virus-cell interaction.
Drug repurposing strategies and key challenges for COVID-19 management
Published in Journal of Drug Targeting, 2022
Shubham Mule, Ajit Singh, Khaled Greish, Amirhossein Sahebkar, Prashant Kesharwani, Rahul Shukla
The ssRNA released into the cell and protein synthesis is done via the host cell machinery with large polyproteins – polyprotein 1a and polyprotein 1ab are formed. Both of these polyproteins then proteolysed into a number of smaller proteins which form ‘replicase–transcriptase complex’ that is ultimately involved in the processes of replication and transcription. This replicase–transcriptase complex combines with viral RNA and lead to the replication of genomic RNA (+) and the formation of antisense genomic RNA (–). This antisense RNA has two fates. It can either be replicated back into the genomic RNA (+) or it can undergo discontinuous transcription. In the discontinuous transcription process, RNA (–) binds with RNA polymerases to initiate transcription at various sites. As a result of discontinuous transcription, the subgenomic mRNAs with different lengths encoding different viral encoded proteins are obtained. Viral proteins are then produced as a result of the translation of these subgenomic mRNAs.
Selection and verification of antibodies against the cytoplasmic domain of M2 of influenza, a transmembrane protein
Published in mAbs, 2020
Nileena Velappan, Sofiya Micheva-Viteva, Samantha H. Adikari, Geoffrey S. Waldo, Antonietta M. Lillo, Andrew R.M. Bradbury
Host-directed therapy is a novel approach proposed to counter the effect of anti-microbial resistance in bacteria and viruses,24 in which host proteins interacting with the pathogen are targeted, rather than the pathogens themselves. Understanding how host proteins interact with viral proteins to regulate host–pathogen interactions is essential for this approach. Cellular pathways such as autophagy and apoptosis are often involved in adaptive immunity.25 Accumulation of auto-phagosomes during influenza infection has been established.26 However, the underlying mechanisms and the host and viral proteins involved in the regulation of autophagy are still under investigation. The cytoplasmic domain of IVA M2 has been postulated as a key regulator of autophagy in IVA-infected cells.27 The anti-M2cyto antibody C2 reported here would be an ideal reagent to study M2 interactions with various host proteins in humans and other animals. Our results also show that our antibody recognizes two different strains of IVA (PR8 and Port Chalmers), and therefore may be useful in studies involving different influenza strains. In our experiments, the stably transfected M2 cell line encoded sequence derived from the PR8 strain of IVA. In order to verify cross-strain specificity of our antibody, we used the Port Chalmers strain of IVA in the viral infection studies presented in Figure 4.
Molecular detections of coronavirus: current and emerging methodologies
Published in Expert Review of Anti-infective Therapy, 2022
Mingkun Diao, Lang Lang, Juan Feng, Rongsong Li
In contrast with antibody detection, antigen-based detections measure the existence of viral antigens in samples. For this assay, specific antibodies against viral proteins are required as the reagent for detection. The assay principle and procedure are similar to antibody detection. Taking the N protein capture ELISA as an example, the capture antibodies against N protein were embedded on the surface of detection wells, when patient samples with N proteins are added in, antigens will be captured by the antibodies. Then detection antibodies against N protein (from an animal host of different species from capture antibody) are added in afterward. The detection antibodies are conjugated with enzymes or linkers for producing detectable signals upon substrate addition.