Search results

Integrins are heterodimeric integral membrane proteins consisting of an ? chain and a ? chain. CD11b is an I-domain including ? integrin combines with the ? 2 chain (ITGB2) to form a leukocyte-specific integrin referred to as macrophage receptor also called MAC1. The ? M beta 2 integrin is crucial in the adherence of neutrophils and monocytes to stimulated endothelium, and also in the phagocytosis of complement coated particles. Multiple transcript variants encoding different isoforms have been found for this gene.

CD8 is a cell surface glycoprotein found on most cytotoxic T lymphocytes that mediates efficient cell-cell interactions within the immune system. CD8 acts as a co-receptor, and the T-cell receptor on the T lymphocyte recognize antigen displayed by an antigen presenting cell (APC) in the context of class I MHC molecules. The functional CD8 is either a homodimer composed of two alpha chains, or a heterodimer composed of one alpha and one beta chain. Both alpha and beta chains share significant homology to immunoglobulin variable light chains.
CD8 identifies cytotoxic/suppressor t-cells that interact with MHC class I bearing targets. CD8 is thought to play a role in the process of t-cell mediated killing. CD8 alpha chains bind to class-I MHC molecules alpha-3 domains.

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.

CD40 is part of the TNF-receptor superfamily. CD40 is a necessary mediator for vast range of immune and inflammatory responses together with T cell-dependent immunoglobulin class switching, memory B cell growth, and germinal center formation. The transcription factor AKNA regulates the expression of CD40 and its ligand, which is vital for homotypic cell interactions. Adaptor protein TNFR2 interacts with CD40 and serves as a mediator of the signal transduction. The interaction of CD40 and its ligand is crucial for amyloid-beta-induced microglial activation, and thus is thought to be an early event in Alzheimer disease pathogenesis. CD40 is the receptor for TNFSF5/CD40L.

CD21 is expressed strongly on mature B cells, follicular dentritic cells and weakly on immature thymocytes and T lymphocytes. In B-cell ontogeny, CD21 appears after the pre-B-stage, is maintained during peripheral B-cell development and is lost upon terminal differentiation into plasma cells. CD21 expression is also gradually lost after stimulation of B cells in vitro. CD21 functions as receptor for C3d, C3dg and iC3b Complement components, for EBV and for IFNalpha. CD21 binds to CD23 and associates with CD19, CD81 and Leu13 to form a large signal-transduction complex involved in B cell activation.

Interleukin-1b is produced by activated macrophages, IL-1B stimulates thymocyte proliferation by inducing il-2 release, b-cell maturation and proliferation, and fibroblast growth factor activity. IL1B proteins are involved in the inflammatory response, being identified as endogenous pyrogens, and are reported to stimulate the release of prostaglandin and collagenase from synovial cells.

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.

SARS Coronavirus is an enveloped virus containing three outer structural proteins, namely the membrane (M), envelope (E), and spike (S) proteins. Spike (S)-glycoprotein of the virus interacts with a cellular receptor and mediates membrane fusion to allow viral entry into susceptible target cells. Accordingly, S-protein plays an important role in virus infection cycle and is the primary target of neutralizing antibodies.It has recently been shown that SARS is caused by a human coronavirus. Human coronaviruses are the major cause of upper respiratory tract illness in humans, such as the common cold. Coronaviruses are positive-stranded RNA viruses, featuring the largest viral RNA genomes known to date (27-31 kb). The first step in coronavirus infection is binding of the viral spike protein, a 139-kDa protein, to certain receptors on host cells. The spike protein is the main surface antigen of the coronavirus. The most prominent protein in the culture supernatants infected with SARS virus is a 46 kDa nucleocapsid protein. This suggests that the nucleocapsid protein is a major immunogen that may be useful for early diagnostics.

Defensins (alpha & beta) are cationic peptides with a wide spectrum of antimicrobial activity which include a significant arm of the innate immune system. There are 6 human beta-defensins, BD-1, BD-2, BD-3, BD-4, BD-5 and BD-6 which are expressed on some leukocytes and at epithelial surfaces. In addition to their direct antimicrobial activities, beta-defensins can act as chemoattractants towards immature dendritic cells and memory T cells. Beta-defensins contain a 6-cysteine motif which forms 3 intra-molecular disulfide bonds.

Defensins form a family of microbicidal and cytotoxic peptides made by neutrophils. Members of the defensin family are highly similar in protein sequence. This gene encodes defensin, beta 103A, which has broad spectrum antimicrobial activity and may play an important role in innate epithelial defense.

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.

HCV is a small 50nm, enveloped, single-stranded, positive sense RNAvirus in the family Flaviviridae.
HCV has a high rate of replication with approximately one trillion particles produced each day in an infected individual. Due to lack of proofreading by the HCV RNA polymerase, the HCV has an exceptionally high mutation rate, a factor that may help it elude the host's immune response. Hepatitis C virus is classified into six genotypes(1-6) with several subtypes within each genotype. The preponderance and distribution of HCV genotypes varies globally. Genotype is clinically important in determining potential response to interferon-based therapy and the required duration of such therapy. Genotypes 1 and 4 are less responsive to interferon-based treatment than are the other genotypes (2, 3, 5 and 6).

Methyl-CpG-binding domain protein 3 (MBD3), belongs to the MBD family of transcriptional repressors. Human proteins MECP2, MBD1, MBD2, MBD3, and MBD4 includes a family of nuclear proteins related by the presence of a methyl-CpG binding domain (MBD) in each protein. Nevertheless, not like the other family members, MBD3 is not capable of binding to methylated DNA. MBD3 is a subunit of the NuRD, a multisubunit complex having nucleosome remodeling and histone deacetylase activities. The predicted MBD3 protein shares 71% and 94% identity with MBD2 (isoform 1) and mouse Mbd3. MBD3 mediates the association of metastasis-associated protein 2 (MTA2) with the core histone deacetylase complex.

Bromodomain Containing 2, also known as BRD2 is a transcriptional regulator which is a member of the BET, bromodomains and extra terminaldomain, family of roteins. BRD2 links with transcription complexes and it acetylated chromatin in the course of mitosis, and it selectively binds o the acetylated lysine-12 residue of histone H4 through its two romodomains. BRD2 maps to the major histocompatability complex MHC) class II region on chromosome 6p21.3, however sequencecomparison advocate that the protein is not implicated in the immune response. BRD2 has been implicated injuvenile myoclonic epilepsy, a common form of epilepsy which grows to be visible in adolescence.

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.
BBeta Defensin is highly expressed by epithelial cells.
Beta-defensin 1 may play a role in the pathogenesis of severe sepsis.
Variation in human Beta Defensin-1 contributes to asthma diagnosis, with apparent gender-specific effects. Human Beta Defensin-3 is a dimer, while Human BD-1 and Human BD-2 are monomeric. The expression of Human BD1 is correlated with induction profiles in gingival keratinocytes.
The level of expression of human DEFB1 mRNA is lower than that of human BD3 and human BD-2 in reconstructed epidermis.
Human BD1 is down-regulated in human prostatic and renal carcinomas.

CD57 also called B3GAT1is part of the glucuronyltransferase gene family. CD57 exhibits strict acceptor specificity, recognizing nonreducing terminal sugars and their anomeric linkages. CD57 takes part in the glucuronyl transfer reaction during the biosynthesis of the carbohydrate epitope HNK-1.

BUD31 is a member of the BUD31 (G10) family. BUD31 is a nuclear protein which contains a putative nuclear translocation sequence, an N-terminal acidic domain and a cysteine-rich C-terminal domain containing a putative Zinc-finger structure. Based on the structure of BUD31 it is suggested that BUD31 might be a nuclear regulator of transcription.

IL2-Ra is one of the three constituent subunits of the IL2 receptor. IL-2Ra is released into the serum after increased cellular expression such as increased activation of B and T cells. Clinical manifestations of IL2-Ra elevation include autoimmune conditions and some leukemias and lymphomas.

CD28 co-stimulation is necessary for CD4 positive T-cell proliferation & survival, interleukin-2 production, and T-helper type-2 development. Human post-thymic regulatory T cells require CD28 co-stimulation to expand and maintain potent suppressive function in vivo. Apoptosis plays a key role in the age-related decline of CD28 expression and in immunosenescence.

Cyclophilin-D is a member of the peptidyl-prolyl cis-trans isomerase (PPIase) family. PPIases catalyze the cis-trans isomerization of proline imidic peptide bonds in oligopeptides and speeds up the protein folding. Cyclophilin-D possess PPIase activity and binds to the immunosuppressant cyclosporin-A. Cyclophilin-D is very well known that its overexpression suppresses the apoptosis in cancer cell. Cyclophilin-D suppresses apoptotic cell death by the use of mitochondrial hexokinase-2 dependent mechanism in cancer cells.

CD45 leukocyte common antigen (LCA) belongs to the family of at least four isoforms of membrane glycoproteins (220, 205, 190, 180kDa) expressed on hematopoietic cell lines but absent on non-hematopoietic cell lines, normal and malignant non-hematopoietic tissues. The intracellular portion of these molecules has protein phosphatase activity and is involved in regulation of transmembrane signals.

HIV-1 and HIV-2 appear to package their RNA differently. HIV-1 binds to any appropriate RNA whereas HIV-2 preferentially binds to mRNA which creates the Gag protein itself. This means that HIV-1 is better able to mutate. HIV-2 is transmitted in the same ways as HIV-1: Through exposure to bodily fluids such as blood, semen, tears and vaginal fluids.
Immunodeficiency develops more slowly with HIV-2.
HIV-2 is less infectious in the early stages of the virus than with HIV-1.
The infectiousness of HIV-2 increases as the virus progresses.
Major differences include reduced pathogenicity of HIV-2 relative to HIV-1, enhanced immune control of HIV-2 infection and often some degree of CD4-independence. Despite considerable sequence and phenotypic differences between HIV-1 and 2 envelopes, structurally they are quite similar. Both membrane-anchored proteins eventually form the 6-helix bundles from the N-terminal and C-terminal regions of the ectodomain, which is common to many viral and cellular fusion proteins and which seems to drive fusion.
HIV-1 gp41 helical regions can form more stable 6-helix bundles than HIV-2 gp41 helical regions however HIV-2 fusion occurs at a lower threshold temperature (25°C), does not require Ca2+ in the medium, is insensitive to treatment of target cells with cytochalasin B, and is not affected by target membrane glycosphingolipid composition.

IFIH1 is a DEAD box protein which is upregulated in response to treatment with beta-interferon and a protein kinase C-activating compound, mezerein. Irreversible reprogramming of melanomas can be attained by therapy with both these agents; treatment with either agent alone only achieves reversible differentiation. DEAD box proteins are implicated in several cellular processes involving alteration of RNA secondary structure such as translation initiation, nuclear and mitochondrial splicing, and ribosome and spliceosome assembly.

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.