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Human immunodeficiency virus (HIV) is a retrovirusthat can lead to a condition in which the immune systembegins to fail, leading to opportunistic infections. HIV primarily infects vital cells in the humanimmune systemsuch as helper T cells(specifically CD4+ T cells), macrophagesand dendritic cells. HIV infection leads to low levels of CD4+ T cells through three main mechanisms: firstly, direct viral killing of infected cells; secondly, increased rates of apoptosisin infected cells; and thirdly, killing of infected CD4+ T cells by CD8 cytotoxic lymphocytesthat recognize infected cells. When CD4+ T cell numbers decline below a critical level, cell-mediated immunityis lost, and the body becomes progressively more susceptible to opportunistic infections. HIV was classified as a member of the genus Lentivirus, part of the family of Retroviridae. Lentiviruses have many common morphologies and biological properties. Many species are infected by lentiviruses, which are characteristically responsible for long-duration illnesses with a long incubation period. Lentiviruses are transmitted as single-stranded, positive-sense, enveloped RNA viruses. Upon entry of the target cell, the viral RNA genomeis converted to double-stranded DNAby a virally encoded reverse transcriptasethat is present in the virus particle. This viral DNA is then integrated into the cellular DNA by a virally encoded integraseso that the genome can be transcribed. Once the virus has infected the cell, two pathways are possible: either the virus becomes latentand the infected cell continues to function, or the virus becomes active and replicates, and a large number of virus particles are liberated that can then infect other cells.

Forty-two antigenic domains were identified across the hepatitis A virus (HAV) polyprotein by using a set of 237 overlapping 20-mer synthetic peptides spanning the entire HAV polyprotein. Nineteen antigenic domains were found within the structural proteins, and 22 were found within the nonstructural proteins, with 1 domain spanning the junction of VP1 and P2A proteins. Five of these domains were considered immunodominant, as judged by both the breadth and the strength of their immunoreactivity. One domain is located within the VP2 protein at position 57-90 aa. A second domain, located at position 767-842 aa, contains the C-terminal part of the VP1 protein and the entire P2A protein. A third domain, located at position 1403-1456 aa, comprises the C-terminal part of the P2C protein and the N-terminal half of the P3A protein. The fourth domain, located at position 1500-1519 aa, includes almost the entire P3B, and the last domain, located at position 1719-1764 aa, contains the C-terminal region of the P3C protein and the N-terminal region of the P3D protein. Four of the five most immunoreactive domains are derived from small HAV proteins and/or encompass protein cleavage sites separating different HAV proteins.

Glycophorins A & B (GYPA &GYPB) are the main sialoglycoproteins of the human erythrocyte membrane which carry the antigenic determinants for the MN and Ss blood groups. Along with the M or N and S or s antigens which normally occur in all populations, approximately 40 related variant phenotypes were identified. These variants comprise all the variants of the Miltenberger complex and some isoforms of Sta, as well as Dantu, Sat, He, Mg, and deletion variants Ena, S-s-U- and Mk. GYPA is significant for the function of SLC4A1 and is necessary for high activity of SLC4A1. GYPA is involved in translocation of SLC4A1 to the plasma membrane. GYPA is also a receptor for: the influenza virus, Plasmodium falciparum erythrocyte-binding antigen 175 (EBA-175); binding of EBA-175 is dependent on sialic acid residues of the O-linked glycans and is also a receptor for Hepatitis A virus (HAV).

The SARS CoV-2 3CL protease (C30 Endopeptidase) derived from human SARS-CoV-2 is a C30-type cysteine protease situated in the NS3 segment. SARS CoV-2 3CL protease biological functionality is needed to process viral polyproteins to functional complete units. SARS CoV-2 3CL protease (main protease) is the core protease protein in CoV and corresponds to non-structural protein 5. SARS CoV-2 3CL cleaves the CoV polyprotein at 11 locations. SARS CoV-2 3CL protease has a cysteine-histidine catalytic dyad at its active site and cleaves a Gln–(Ser/Ala/Gly) peptide bond. SARS CoV-2 3CL protease at position P1 cleaves the bond between the glutamine and serine/alanine/glycine. SARS CoV-2 3CL protease is necessary in the processing of the CoV replicase polyprotein.

The cytokine Macrophage migration inhibitory factor (MIF) has been identified to be secreted by the pituitary gland and the monocyte/macrophage and to play an important role in endotoxic shock. MIF has the unique property of being released from macrophages and T cells in response to physiological concentrations of glucocorticoids. The secretion of MIF is tightly regulated and decreases at high, anti-inflammatory steroid concentration.

FADD is an adaptor protein that cooperates with a variety of cell surface receptors and mediates cell apoptotic signals. Using its C-terminal death domain, FADD is recruited by TNFRSF6/Fas-receptor, tumor necrosis factor receptor, TNFRSF25, and TNFSF10/TRAIL-receptor, and consequently it take parts in the death signaling initiated by these receptors. FADD interaction with the receptors reviels the N-terminal effector domain of, which allows it to recruit caspase-8, and thus initiate the cysteine protease cascade. Knockout studies in mice furthermore propose the significance of FADD in premature T cell development. FADD plays a role in survival/proliferation and cell cycle development. FADD also takes part in cellular sublocalization, protein phosphorylation, and inhibitory molecules.

Vimentin expression in human malignant glioma cells depends on cellular density, algorithms of drug delivery and chemo/radio treatment. Vimentin and detyrosinated microtubules provide structural support for the extensive microtentacles observed in detached tumor cells and a mechanism to promote successful metastatic spread. Primary colorectal carcinomas display aberrant expression of vimentin, and have activated Notch and TGFbeta signaling pathways. Vimentin is a strong arterial substrate for transglutaminases. Transglutaminase-mediated vimentin dimerization results in a novel unifying pathway by which vasodilatory and remodeling responses may be regulated. Ablation of vimentin expression inhibits migration and invasion of colon and breast cancer cell lines.

The Defensin family are highly similar in their protein sequence and are microbicidal & cytotoxic peptides made by neutrophils. Beta Defensin-1 is an antimicrobial peptide having the resistance of epithelial surfaces to microbial colonization. Beta Defensin-1 has close proximity to Defensin Alpha-1 and has been implicated in the pathogenesis of cystic fibrosis.
Skin of patients having atopic dermatitis patients and mycosis fungoides (non-lesional and lesional) show lower human Beta Defensin-1 mRNA expression and higher human Beta Defensin-2 and human Beta Defensin-3 mRNA expression.
Beta Defensin is highly expressed by epithelial cells.
Beta-defensin 1 may play a role in the pathogenesis of severe sepsis.

Entry of HSV into the host cell involves interactions of several viral glycoproteins with cell surface receptors. The virus particle is covered by an envelope which, when bound to specific receptors on the cell surface, will fuse with the cell membrane and create an opening, or pore, through which the virus enters the host cell. The sequential stages of HSV entry are analagous to those of other viruses. At first, complementary receptors on the virus and cell surface bring the two membranes into proximity. In an intermediate state, the two membranes begin to merge, forming a hemifusion state. Finally, a stable entry pore is formed through which the viral envelope contents are introduced to the host cell.

Autophagy Related 3 (ATG3) is a conjugating enzyme essential for the cytoplasm to vacuole transport (Cvt), autophagy, and mitochondrial homeostasis. ATG3 is localizes to the cytoplasm and is expressed in tissues with predominant levels found in kidney, placenta, liver, heart and skeletal muscle. ATG3 catalyzes a reaction which is necessary for autophagy. That reaction is the formation of the Atg8-phosphatidylethanolamine (ATG-PE) conjugate.

Ganciclovir (GCV) is a pro-drug nucleoside analog that is activated by phosphorylation. It is useful in the study of gene therapy in cancer research.
Ganciclovir is a synthetic analogue of 2'-deoxy-guanosine. It is initially phosphorylated to a deoxyguanosine triphosphate (dGTP) analogue. This mechanism competitively inhibits the integration of dGTP by viral DNA polymerase, resulting in the termination of elongation of viral DNA. Upon expression of a viral suicide gene encoding thymidine kinase, the non-toxic pro-drug is converted to a phosphorylated active analog and is incorporated into the DNA of replicating eukaryotic cells, causing death of the malignant dividing cell. The cell cycle is irreversibly arrested at the G2-M checkpoint. Gap junction involvement in the ganciclovir bystander effect has been studied. Ganciclovir has been used to study loss of telomeres and to evaluate sensitivity of viruses to antiviral treatments.
Ganciclovir is used in molecular biology for selection against random recombination events when homologous recombination of a gene of interest is required.

SARS Membrane protein is a membranal protein which plays a crucial role in the virus’ life cycle. This protein has 3 outer cell structural antigens, the envelope (E), membrane (M)and spike (S) antigens. SARS Membrane protein is essential to the process of assembly, budding, creation of the envelope and pathogenesis.

IFN-gamma produced by lymphocytes activated by specific antigens or mitogens.
IFN-gamma, in addition to having antiviral activity, has important immunoregulatory functions, it is a potent activator of macrophages, and has antiproliferative effects on transformed cells and it can potentiate the antiviral and antitumor effects of the type I interferons.

FKBP4 is part of the immunophilin protein family, which takes part in immunoregulation and necessary cellular processes concerning protein folding and trafficking. FKBP4 is a cis-trans prolyl isomerase that connects to the immunosuppressants FK506 and rapamycin. FKBP4 has high structural and functional similarity to FKBP1A, though, FKBP4 does not have immunosuppressant activity when complexed with FK506. FKBP4 interacts with interferon regulatory factor-4 and is involved in immunoregulatory gene expression in B and T lymphocytes. FKBP4 is known to connect with phytanoyl-CoA alpha-hydroxylase. FKBP4 associates with HSP90 & HSP70 thus takes part in the intracellular trafficking of hetero-oligomeric forms of the steroid hormone receptors. FKBP4 highly associates with adeno-associated virus type 2 vectors (AAV) resulting in a considerable increase in AAV-mediated transgene expression in human cell lines. FKBP4 is involved in the optimal use of AAV vectors in human gene therapy.

A human infecting coronavirus (viral pneumonia) called 2019 novel coronavirus, 2019-nCoV was found in the fish market at the city of Wuhan, Hubei province of China on December 2019.

The 2019-nCoV shares an 87% identity to the 2 bat-derived severe acute respiratory syndrome 2018 SARS-CoV-2 located in Zhoushan of eastern China. 2019-nCoV has an analogous receptor-BD-structure to that of 2018 SARS-CoV, even though there is a.a. diversity so thus the 2019-nCoV might bind to ACE2 receptor protein (angiotensin-converting enzyme 2) in humans.

While bats are possibly the host of 2019-nCoV, researchers suspect that animal from the ocean sold at the seafood market was an intermediate host. RSCU analysis proposes that the 2019-nCoV is a recombinant within the viral spike glycoprotein between the bat coronavirus and an unknown coronavirus.

CD4 is a cell-surface glycoprotein found on the mature helper T cells and immature thymocytes, as well as on monocytes and macrophages. (Some cytotoxic T cells have CD4 protein as well.) Normally, about 65% of T cells in the blood are CD4+ (have CD4 protein protruding from their membrane). A mature T cell with either have CD4 or CD8, but not both. During one stage of development T cells develop CD4 and CD8 receptors, but they eventually are differentiated in the thymus and become more specialized.

A human infecting coronavirus (viral pneumonia) called 2019 novel coronavirus, 2019-nCoV was found in the fish market at the city of Wuhan, Hubei province of China on December 2019.

The 2019-nCoV shares an 87% identity to the 2 bat-derived severe acute respiratory syndrome 2018 SARS-CoV-2 located in Zhoushan of eastern China. 2019-nCoV has an analogous receptor-BD-structure to that of 2018 SARS-CoV, even though there is a.a. diversity so thus the 2019-nCoV might bind to ACE2 receptor protein (angiotensin-converting enzyme 2) in humans.

While bats are possibly the host of 2019-nCoV, researchers suspect that animal from the ocean sold at the seafood market was an intermediate host. RSCU analysis proposes that the 2019-nCoV is a recombinant within the viral spike glycoprotein between the bat coronavirus and an unknown coronavirus.

p53 is a tumor suppressor gene expressed in a wide variety of tissue types and is involved in regulating cell growth, replication, and apoptosis. It binds to mdm2, SV40 T antigen and human papilloma virus E6 protein p53 senses DNA damage and possibly facilitating repair. Mutation involving p53 is found in a wide variety of malignant tumors, including breast, ovarian, bladder, colon, lung, and melanoma.

HAX1 associates with hematopoietic cell-specific Lyn substrate 1, which is a substrate of Src family tyrosine kinases. HAX1 also interacts with the product of the polycystic kidney disease 2 gene, mutations in which are associated with autosomal-dominant polycystic kidney disease, and with the F-actin-binding protein, cortactin. It was earlier thought HAX1 is mainly localized to the mitochondria, however, recent studies indicate it to be localized in the cell body. Mutations in the HAX1 gene result in autosomal recessive severe congenital neutropenia, aka Kostmann disease.

AGXT is expressed only in the liver and its protein is localized mostly in the peroxisomes, where it is involved in glyoxylate detoxification. Mutations in the AGXT gene, some of which alter subcellular targetting, have been linked to type I primary hyperoxaluria.

CD58 is part of the immunoglobulin superfamily. CD58 is a ligand of the T lymphocyte CD2 protein, and is invloved in adhesion and activation of T lymphocytes. CD58 is localized to the plasma membrane.

HSP27 (also known as the Estrogen-Regulated 24K protein, and hsp 28) is a member of the mammalian small heat shock protein family. Hsp27 is expressed constitutively in many tissues and its expression is increased to high levels after various types of stress including elevated temperatures, toxic metals, drugs and oxidants. Also, Hsp27 is phosphorylated in vivo on three phosphorylation sites (Ser15, Ser78 and Ser82) by protein kinases including MAPKAP kinase 2 and the stress-activated protein kinase SAPK2 (p38).