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Hepatitis B is one of a few known non-retroviralviruses which employ reverse transcriptionas a part of its replication process. (HIV, a completely unrelated virus, also uses reverse transcription, but it is a retrovirus.) HBV invades the cell by binding to surface receptor and become internalized. The viral core particles then migrate to the hepatocyte nucleus and the partially double-stranded, relaxed circular genomes (RC-DNA) are repaired to form a covalently closed circular DNA (cccDNA), which is the template for viral genomic and sub-genomic RNAs by cellular RNA polymerase II. Of these, the pregenomic RNA (pgRNA is selectively packaged into progeny capsids and is then reverse-transcribed into new RC-DNA. The core can either bud into the endoplasmic reticulum to be enveloped or exported from the cell or recycled back into the genome for conversion to cccDNA.

Treponema pallidum is a gram-negative spirochaete bacterium and is considered to be metabolically crippled. There are at least four known subspecies: T. pallidum pallidum, T. pallidum pertenue, T. pallidum carateum and T. pallidum endemicum. The helical structure of T. pallidum pallidum allows it to move in a corkscrew motion through viscous mediums such as mucus. Treponema pallidum sub sp. pallidum has one of the smallest bacterial genomes at 1.14 million base pairs (Mb) and has limited metabolic capabilities, reflecting its adaptation through genome reduction to the rich environment of mammalian tissue.

Macrophage Inflammatory Proteins belong to the family of chemotactic cytokines known as chemokines. In humans, there are two major forms, MIP-1a and MIP-1b that are now also named CCL3 and CCL4. Both factors are produced by macrophages after they are stimulated with bacterial endotoxins. MIP-1a and MIP-1b activate human granulocytes (neutrophils, eosinophils and basophils) which can lead to acute neutrophilic inflammation. MIP-1a and MIP-1b induce synthesis and release of other pro-inflammatory cytokines such as interleukin-1 (IL-1), IL-6 and TNF-alpha from fibroblasts and macrophages. CCL3 and CCL4 genes are both located on human chromosome 17.

The life cycle of Toxoplasma gondii has two phases. The coccidia like takes place only in members of the Felidae family which makes these animals the parasite's primary host. The asexual part of the life cycle can take place in any warm-blooded animal, like other mammals(including felines) and birds. T. gondii constructing daughter scaffolds within the mother cell. In the intermediate hosts (including felines), the parasite invades cells, forming intracellular so-called parasitophorous vacuoles containing bradyzoites, the slowly replicating form of the parasit. Vacuoles form tissue cysts mainly within the muscles and brain. Since they are within cells, the host's immune system does not detect these cysts. Resistance to antibiotics varies, but the cysts are very difficult to eradicate entirely. Within these vacuoles T. gondii propagates by a series of binary fissions until the infected cell eventually bursts and tachyzoites are released. Tachyzoites are the motile, asexually reproducing form of the parasite. Unlike the bradyzoites, the free tachyzoites are usually efficiently cleared by the host's immune response, although some manage to infect cells and form bradyzoites, thus maintaining the infection.

CMV belongs to the Betaherpesvirinae subfamily of Herpesviridae which includes herpes simplex virustypes 1 and 2, varicella-zoster virus, and Epstein-Barrvirus. The herpesviruses share a characteristic ability to remain latentover long periods. CMV is a double-stranded linear DNA virus with 162 hexagonal protein capsomeres surrounded by a lipid membrane. CMV has the largest genome of the herpes viruses, ranging from 230-240 kilobase pairs. Human CMV is composed of unique and inverted repeats that include the existence of 4 genome isomers caused by inversion of L-S genome components (class E). Replication may be divided into immediate early, delayed early, and late gene expression based on time of synthesis after infection. The DNA is replicated by rolling circles. In vitro, CMV replicates in human fibroblasts.

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.

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.

Human T-lymphotropic virus (HTLV) is a human, single-stranded RNA retrovirus that causes T-cell leukemia and T-cell lymphoma. The virus activates a subset of T-helper cellscalled Th1cells. The result is a proliferation of Th1 cells and overproduction of Th1 related cytokines (mainly IFN-gamma and TNF-alpha). Feedback mechanisms of these cytokines cause a suppression of the Th2 lymphocytes and a reduction of Th2 cytokine production (mainly IL-4, IL-5, IL-10 and IL-13). The end result is a reduction in the ability of the infected host to mount an adequate immune response to invading organisms that require a predominantly Th2 dependant response (these include parasitic infections and production of mucosal and humoral antibodies).

Human norovirus is classified into two groups, group 1& group 2. Norwalk virus is the species which belongs to group 1 and was discovered in 1968 at Ohio. Norovirus is a familiar virus which causes human gastroenteritis with the following symptoms vomiting, diarrhea and sickness. CDC report revealed that there are 19-21 million Americans infected by Nororvirus annually with 800 deaths, 1 in 15 people with infection. Around the world, this virus affects about 267 million people and causes over 200,000 deaths each year; these losses are mostly in less developed countries and in the very young, elderly and immuno-suppressed population, though, most cases are self-limited with a full recovery within just a few days. Norovirus is extremely contagious and can spread from human to human through infected food, water or contaminated surfaces. The outbreaks usually occur from November-April, while the peak is in January. Norovirus is a positive sense RNA virus with 7.5 kb nucleotides, encoding a major structural protein VP1 with 50-55kDa. The full length of VP1 capsid comprises the internal N-terminal, Hinge, shell (S) and protruding (P) domains. P domain from 225 to 520 forms P1- P2-P1 structure. Moreover, P domain has a receptor binding region which recognizes human histo-blood group antigens (HBGAs). P domain expressed in bacteria can spontaneously form a P dime as well as a P particle aggregated by 12 P dimmers. P particle displays an increased binding activity to HBGAs higher than virus-like particle (VLP) formed by the full-length capsid. For norovirus vaccine development, we consider P domain as a good candidate.

The Epstein-Barr virus (EBV), also called Human herpes virus 4 (HHV-4), is a virusof the herpes family(which includes Herpes simplex virusand Cytomegalovirus. On infecting the B-lymphocyte, the linear virus genome circularizes and the virus subsequently persists within the cell as an episome. The virus can execute several distinct programs of gene expressionwhich can be broadly categorized as being lytic cycle or latent cycle. The lytic cycleor productive infection results in staged expression of a host of viral proteinswith the ultimate objective of producing infectious virions. Formally, this phase of infection does not inevitably lead to lysis of the host cellas EBV virions are produced by budding from the infected cell. The latent cycle(lysogenic) programs are those that do not result in production of virions. A very limited, distinct set of viral proteins are produced during latent cycle infection. These include Epstein-Barr nuclear antigen(EBNA)-1, EBNA-2, EBNA-3A, EBNA-3B, EBNA-3C, EBNA-leader protein (EBNA-LP) and latent membrane proteins(LMP)-1, LMP-2A and LMP-2B and the Epstein-Barr encoded RNAs(EBERs).

BTC is a potent mitogen for retinal pigment epithelial cells and vascular smooth muscle cells. The effects of betacellulin are mediated by the EGF receptor and other related receptors.

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.

Glucokinase or GLK, is a protein, part of the bacterial glucokinase superfamily. In the bacteria E. coli, glucose can be transported to the inner cell through a system called PTS as glucose 6-phosphate, therefore, GLK is less crucial to the bacteria.

CCL-20 is a chemotactic factor that draws lymphocytes & neutrophils, rathar than monocytes. MIP-3 alpha inhibits proliferation of myeloid progenitors in colony formation assays. MIP3A plays a role in the formation and function of the mucosal lymphoid tissues by attracting lymphocytes and dendritic cells towards epithelial cells. C-terminal processed forms have been shown to be equally chemotactically active for leukocytes. CCL-20 holdes antibacterial activity e.coli atcc 25922 and s.aureus atcc 29213. CCL-20 gene transcription is activated by H. pylori, which activates NF-kappaB through intracellular signal pathway which involves IkappaB kinase and NF-kappaB-inducing kinase. MIP-3 alpha is invloved in chemokine-mediated lymphocyte trafficking during gastric inflammation in Helicobacter infection. CCL-20 expression is involved in the recruitment of CD45R0-positive T cell subsets into the intestinal lamina propria. MIP-3A is in charge of the advancement of pulpal inflammation through the recruitment of C-C motif Receptor 6-expressing lymphocytes Vaginal epithelial cells respond to factors present in semen by secreting MIP-3 alpha, which increases langerhans cells recruitment during HIV transmission.

Borrelia belongs to a genus of bacteria of the spirochete phylum. Borrelia causes borreliosis, which is a zoonotic, vector-borne disease transmitted mainly by ticks and some by lice, depending on the species. Of the 36 known species of Borrelia, 12 are distinguished to cause Lyme disease or borreliosis and are transmitted by ticks. The main Borrelia species causing Lyme disease are Borrelia burgdorferi, Borrelia afzelii, and Borrelia garinii. The Borrelia genus members have a linear chromosome which is about 900 kbp in length as well as an excess of both linear and circular plasmids in the 5-220 kbp size range. The plasmids are atypical, as compared to most bacterial plasmids, since they contain many paralogous sequences, a large number of pseudogenes and, in some cases, essential genes. Moreover, a number of the plasmids have features suggesting that they are prophages.

Borrelia belongs to a genus of bacteria of the spirochete phylum. Borrelia causes borreliosis, which is a zoonotic, vector-borne disease transmitted mainly by ticks and some by lice, depending on the species. Of the 36 known species of Borrelia, 12 are distinguished to cause Lyme disease or borreliosis and are transmitted by ticks. The main Borrelia species causing Lyme disease are Borrelia burgdorferi, Borrelia afzelii, and Borrelia garinii. The Borrelia genus members have a linear chromosome which is about 900 kbp in length as well as an excess of both linear and circular plasmids in the 5-220 kbp size range. The plasmids are atypical, as compared to most bacterial plasmids, since they contain many paralogous sequences, a large number of pseudogenes and, in some cases, essential genes. Moreover, a number of the plasmids have features suggesting that they are prophages.

Listeria monocytogenes is a pathogenic bacteria that manufactures flagella.At 37 °C inside humans, it causes MogR to repress the expression of flagellar proteins, thus stopping the manufacturing of flagella. Though, in the low-temperatures externally of the host, the GmaR inactivates MogR, enabling flagellar formation.

Treponema pallidum is a gram-negative spirochaete bacterium and is considered to be metabolically crippled. There are at least four known subspecies: T. pallidum pallidum, T. pallidum pertenue, T. pallidum carateum and T. pallidum endemicum. The helical structure of T. pallidum pallidum allows it to move in a corkscrew motion through viscous mediums such as mucus. Treponema pallidum sub sp. pallidum has one of the smallest bacterial genomes at 1.14 million base pairs (Mb) and has limited metabolic capabilities, reflecting its adaptation through genome reduction to the rich environment of mammalian tissue.

Salmonella Typhi is a pathogen causing typhoid fever, affecting over 17 million people with approximately 600,000 deaths annually worldwide. If untreated, typhoid fever cases result in mortality rates ranging from 12-30%.

Adiponectin is a recently discovered 244 amino acid protein, the product of the apM1 gene, which is physiologically active and specifically and highly expressed in adipose cells (Adipokine). The protein belongs to the soluble defense collagen super family; it has a collagen-like domain structurally homologous with collagen VIII and X and complement factor C1q-like globular domain. APM-1 forms homotrimers, which are the building blocks for higher order complexes found circulating in serum.

P4HB is a multifunctional and highly abundant enzyme that is part of the protein disulfide isomerase family. When present as a tetramer consisting of two alpha and two beta subunits, P4HB has a role in hydroxylation of prolyl residues in preprocollagen. P4HB is a disulfide isomerase containing two thioredoxin domains that catalyze the formation, breakage and rearrangement of disulfide bonds.

HBsAg is the surface antigen of the Hepatitis-B-Virus (HBV). The capsid of a virus has different surface proteins from the rest of the virus. The antigen is a protein that binds specifically on one of these surface proteins and is commonly referred to as the Australian Antigen. HBsAg is an essential parameter to diagnose hepatitis B disease in the clinic and to monitor antiviral treatment.

HBsAg is the surface antigen of the Hepatitis-B-Virus (HBV). The capsid of a virus has different surface proteins from the rest of the virus. The antigen is a protein that binds specifically on one of these surface proteins. It is commonly referred to as the Australian Antigen.
Recombinant HbsAg ayw full length is a 24kDa protein cloned from HBV 320 genome.

Salmonella Typhi is a pathogen causing typhoid fever, affecting over 17 million people with approximately 600,000 deaths annually worldwide. If untreated, typhoid fever cases result in mortality rates ranging from 12-30%.