T Cell Lab Report

Viruses are microscopic particles that invade and take over both eukaryotic and prokaryotic cells. They consist of two structures, which are the nucleic acid and capsid. The nucleic acid contains all genetic material in the form of DNA or RNA, and is enclosed in the capsid, which is the protein coating that helps the virus attach to and penetrate the host cell. In some cases, certain viruses have a membrane surrounding the capsid, called an envelope. This structure allows viruses to become more stealthy and protected. There are two cycles in which a virus can go into: lytic and lysogenic. The lytic cycle consists of the virus attaching to a cell, injecting its DNA, and creating more viruses, which proceed to destroy the host. On the other hand, the lysogenic cycle includes the virus attaching to the cell, injecting its DNA, which combines with the cell’s DNA in order for it to become provirus. Then, the provirus DNA may eventually switch to the lytic cycle and destroy the host.

The virus fuses with the cell’s plasma membrane. The capsid proteins are removed, releasing the viral proteins and RNA. Reverse transcriptase catalyzes the synthesis of a DNA strand complementary to the viral RNA. Reverse transcriptase catalyzes the synthesis of a second DNA strand complementary to the first. The double-stranded DNA is incorporated as a provirus into the cell’s DNA. Proviral genes are transcribed into RNA molecules, which serve as genomes for the next viral generation and as mRNAs for translation into viral proteins. The viral proteins include capsid proteins and reverse transcriptase (made in the cytosol) and envelope glycoproteins (made in the ER). Vesicles transport the glycoproteins from the ER to the cell’s plasma membrane. Capsids are assembled around viral genomes and reverse transcriptase molecules. New viruses bud off from the host cell.

CD4 is a glycoprotein found on the surface of immune cells such as T helper cells, monocytes, macrophages, and dendritic cells. HIV infects cells of the immune system called T lymphocytes (T cells) and macrophages. HIV has an envelope and contains two copies of single-stranded RNA as the genome. Within the viral capsid are important viral enzymes called reverse transcriptase, integrase, and protease. The HIV virus has a spike protein that is called gp120, and the host cell receptor is CD4+. HIV belongs to a class of viruses called retroviruses. Retroviruses are RNA viruses, and to replicate or reproduce, they must make a DNA copy of their RNA through transcription and translation. It is the DNA genes that allow the

On 07/11/2015 at the Lower Buckeye Jail (located at the above listed address) I was assigned as the floor officer for Tower 12. At approximately 1555 hours, Inmate Asad, Sami T188658 (V1) came out to Level 1 core stating that he had been hit in the back of the head multiple times inside his cell in T12 B pod. Inmate Asad was placed into the level 1 holding tank awaiting medical.

Once tightly bound the virus is endocytosed via coated vesicles. The virus is transported into late endosomes which acidify their content and hence induce conformational rearrangement of HA exposing the fusiogenic peptide sequence. The loop region of the HA becomes a coiled coil that mediates membrane fusion. The release of viral genome into the cytoplasm also requires protons that are pumped from the acidic endosome into the virion interior via the matrix protein M2 that acts as a proton channel. Viral RNA dissociates from M1 and is then imported in an ATP-dependent manner into the nucleus for transcription and translation. In humans, the replication of the influenza virus is usually restricted to the airways epithelial cells due to the limited expression of a serine protease, produced by nonciliated bronchial epithelial cells and which cleaves the HA precursor in HA1 and HA2 polypeptides, rendering the virions infectious. Replication and virions production occurs within hours after virus entry. The viral ribonucleoprotein (vRNP) complexes are released from the endosomes into the cytoplasm and subsequently transported to the nucleus, where replication and transcription take

Treatment development focused on limiting the virus' ability to transcribe and replicate copies of itself within the host cell. Reverse transcriptase is an enzyme coded by the virus RNA. Reverse transcriptase (RT) allows the RNA to make a functioning DNA copy that is inserted into the host cell DNA and begin manufacturing copies of new viral RNA identical to the strands in the initial viron. RT is found only in retroviruses and focus on AIDS treatment has been on inhibiting the function of RT in HIV action within a host cell( Furman, P. A. Fyfe, J. A. St.Clair, M. H.; Wenhold, J. Rideout, J. L., Broder, S., Mitsuya, H.; Barry, D. W. 1985).

The HI–Virus needs a host cell to multiply. Like all viruses the HI-Virus is not an independent organism and requires a foreign metabolism to survive. It consists of an outer envelope, which contains the docking points for the connection with the host cell. The inner capsule contains the building plan of the virus – the RNA. The HI-Virus contains also a protein coat with the enzymes. It must penetrate a human cell, introduce its hereditary informations1 and reprogram the cell that it produces the building blocks for the viral protein. The target of the HI-Virus is the cell that carries the CD4 antigen on their surface. CD4-Antigens are certain proteins molecules on the surface of the cells, which serve as receptors for the HI-Virus.

The G protein binds to cells and starts the infection. The virus __uncoats__ inside the cell, which means that the RNP is released into the cytoplasm where viral replication take place. The first step is for the virus to make its proteins. The viral RNA is used as a template for the L protein to transcribe messenger RNAs (mRNAs). These mRNAs tell the cell's ribosomes to make viral proteins instead of the cell's proteins. Once enough viral proteins are made, the L protein starts to make new copies of the viral genome. This RNA is bound by new copies of the L, P, and N protein forming new RNPs. These are covered with M protein and then gain an envelope with the G protein as it leaves the cell forming a new infectious

Upon binding the virus enters human cells via receptor-mediated endocytosis and forms a vesicle known as an endosome.

Around since the second world war (8), it is a retrovirus that has the ability to transcribe its RNA into a copy of DNA in the host cell (1). It can take up to 6 months for the presence of HIV – specific antibodies to become detectable (2) however, throughout this period the HIV antigen and RNA can be detected in the blood (2).

The molecular pathway of HIV is similar to most viruses as it begins it’s cycle during the transfer of bodily fluids from one infected person to another non infected person. Once this occurs HIV must attempt to cross the cell layer this can occur through tears in the skin or open wounds. The chance of this happening depends on the viral load or the amount of exposure. Once crossing the cell layer the virus comes into contact with immune cells which attempt to destroy the viruses. These immune cells or CD4 cells serve as the host cells for HIV. The host cell can be a variety of immune cells such as macrophages, dendritic, t helper cells and perhaps most importantly damage B cells. The damage of B cells is significant because they are memory cells that essentially store the recipes to make antibodies to various diseases and viruses they have been exposed to in the past. The immune cells attempt to take up the viruses and destroy them. However, a gene called Vpu facilitates the production of the a protein that prevents immune cells from being able to destroy it. Vpu prevents the destruction of itself by the immune system which then allows them to invade the host cell. Once inside the cell the virus begins its cycle and unpacks its genetic information. Then the process

The protective capsid helps the virus escape detection and destruction during the invasion of the host. When the virus reaches the target cell, biochemical reactions between the capsid and cell wall allow the virus to latch on and inject its genome into the cell’s interior. Once inside, the viral genetic material insinuates itself into the host’s DNA or RNA. In an efficient feat of natural bioengineering, the host cell’s genetic machinery now does the rest of the work for the virus. The cell, which had already been making copies of its own genome, now also replicates that of the virus. Coded within the viral material is the blueprint for making more copies of the viral genome. Further instructions command the production of capsids and directions for assembly of new viruses. After the host cell becomes engorged with viruses, it explodes, sending the new

This RNA genome is bound to nucleocapsid proteins as well as the enzymes needed for the development of the virion. These are enclosed by a cone-shaped capsid. A matrix that is composed of another protein surrounds the capsid, which is in turn, surrounded by the viral envelope that is composed of two phospholipid layers derived from the host human cell membrane when a newly formed virus budded from the cell. There are proteins embedded in this envelope that stick out through the surface of the virus membrane and allow the virus to connect and fuse with target cells in order to begin infecting those cells. These embedded proteins are glycoprotein complexes that consist of a cap called gp120, and a stem called gp41which anchors the complex in the envelope.

The HIV-1 virion is approximately 120 nm in diameter, roughly spherical, and is composed of two copies of a single stranded positive sense RNA enclosed by a capsid (24). The HIV-1 genome is less than 10 kb and encodes for more than nine different gene products. It encodes for 3 major structural protein genes: gag (group-specific antigen), pol (DNA polymerase), and env (Envelope), which code for major structural proteins and essential enzymes. Gag generates the mature Gag protein matrix (MA or p17), capsid (CA or p24), nucleocapsid (NC or p7), and p6, which encompass proteins for the basic infrastructure of the virus such as the inner core of the viral particle (25). Pol encodes for reverse transcriptase (RT), which enables the virus to reproduce, integrase (IN), which is necessary to integrate the viral double stranded DNA into the host genome, RNAse H, and HIV protease, which are all encapsulated in the core of the inner particle formed by the viral capsid protein p24 (25). Env encodes for glycoproteins of the outer membrane such as outer gp120 (which enables the virus to attach and fuse to cells of the host), and transmembrane gp41 that anchors the glycoprotein complex to the surface of the virion (25). Between the core and the envelope is the HIV matrix proteins which are composed of the viral protein p17 (23). HIV-1 also encodes for proteins with important regulatory elements (tat (Trans-Activator of Transcription) and rev

The HIV belongs to the genus Lentivirus and the family Retroviridae. The members of the genus Lentivirus have different morphology and associate biological properties common for all. These viruses also infect and affect many species of the animal kingdom; the most affected being the human species. However, in the structures, the HIV has a relatively different structure from the other retroviruses. The HIV causing virus has a roughly spherical structure with a diameter of approximately 120 nm and around 60 times smaller than a red blood cell (Lowe 8). However, it is larger than the general structure of a virus. The