The hiv life cycle defines the steps and changes the virus undergoes from its first contact with a target cell to the production of new infectious viral particles that can initiate the next round of replication. The series of steps that hiv follows to multiply in the body. The viral envelope merges with the cell plasma membrane middle releasing the matrix shell and core purple bulletshaped structure containing the viral genome into the cell. This video explains how hiv targets human immune cells, and uses immune cell machinery to make copies of itself. This video lecture explains the life cycle of hiv virus and the infection strategy of hiv in causing aids. The gag proteins of hiv 1, like those of other retroviruses, are necessary and sufficient for the assembly of virus like particles. Author summary viral pathogens, such as hiv1, are fully dependent of the cellular machinery to complete the replication cycle. Hiv life cycle, innate immunity, and autophagy in the central. Hiv virus life cycle hiv predator, today learn about the life cycle of hiv virus, how do we benefit from knowing that this pathogen cuased the disease can develop treatments and prevention methods, why would know the parts of the life cycle of hiv be useful so you can target specific parts of the life cycle can develop drug targets, viruses olgate. So you can target specific parts of the life cycle can develop drug targets, viruses olgate parasite, piratetake over the cell and get the body cell to ake more of hiv only 10,000 bases in its genome of hiv, human has 3 billion basess in the genome viruses dont have ribosomes to make proteins, so they have to hijack the cells. The life cycle of hiv and hiv disease december 2011possible benefits of starting at 350500 an increasing number of observational results and early clinical studies suggest lower rates of aids and other healthrelated. Its a structural protein that plays multiple roles in the life cycle of the hiv virus, including viral replication and particle assembly. An interactive 3d presentation of the life cycle of the hiv virus by hybridmedicalanimation.
Integration insertion of the viral dna into host chromosomal dna, essential step in cycle point of no return. The cell offers a permissive environment, and deploys a number of antiviral defense strategies. The life cycle of the hiv virus is a multistep process. The roles played by hiv 1 gag proteins during the life cycle are numerous and complex, involving not only assembly but also virion maturation after particle release and early postentry steps in virus replication. Inhibition of human immunodeficiency virus type1 through autophagy.
Lecture hiv virus life cycle lecture notes hiv virus. Current first line regimens are more ef fective and easier to take and tolerate, which helps. Each of these steps is used as a target to make hiv drugs to inhibit the progress of hiv infection. Cd4 is a 58 kda monomeric glycoprotein that can be detected on the cell surface of about 60% of t lymphocytes, on t cell precursors within the bone marrow and thymus, and on monocytes and macrophages, eosinophils, dendritic cells and microglial cells of the central nervous.
The daily cycle of hiv production and t helper lymphocyte destruction. Instead, the virus attaches itself to a thelper cell and fuses with it. Each step in the hiv 1 life cycle is a potential target for antiviral intervention 165. The viral rna yellow stringlike structure in core is converted into viral dna red stringlike structure in core by the. Hiv aids virus replication viral life cycle diagram by. Definitionthe hiv life cycle defines the steps and changes the virus undergoes from its first contact with a target cell to the production of new infectious viral particles that can initiate the. Human immunodeficiency virus hiv particle upper right attaches to cell surface. Students will understand how the hiv viral pathway may be interrupted to prevent the spread of the virus in an individual 2. Fact sheets about hivaids treatment information, the prevention of motherto child transmission, and hiv treatment side effects. Vpx hiv2 only are presumably transported to the nucleus where it would act to. The gp120 attaches to the attachement receptor cd4. The hiv life cycle and antiretroviral drugs part 1. The lytic cycle is one of the two stages of viral replication. The shell of the capsid disintegrates and the hiv protein called reverse transcriptase transcribes the viral rna into dna.
This animation describes the structure of the hiv virus, receptormediated attachment to. Pathophysiology of the human immunodeficiency virus baylor. The type of virus, the cells it targets, where it replicates and proliferates in the human body and why hiv is so. As the virus replicates and spreads throughout the body, the immune system detects the presence of the virus and mounts an immediate antibody response. People transmit hiv through a very specific list of bodily fluids. These particles will be borne in fluid such as blood or semen, since the hiv virus cannot survive on its own outside. Ccr5 protein on the helper t cell allows the membranes of the virus and cell to fuse. The lytic cycle of hiv includes the time when the viral dna exists in the host cell. Understanding the life cycle of hiv has made it possible to develop the drugs we use to treat the disease.
The hiv matrix protein lies between the envelope and core. During the last two decades, the profusion of hiv research due to the urge to identify new therapeutic targets has led to a wealth of information on the retroviral replication cycle. Early steps of retrovirus replicative cycle retrovirology. The 3d model of the mature virion was generated using cellpack by graham johnson illustrations of the major steps of hiv life cycle are presented that integrate information from structural and biophysical studies. Hiv virology and pathogenetic mechanisms of infection. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Also, an extensive listing of aidsrelated internet web site addresses. Hiv uses the machinery of the cd4 cells to multiply and spread throughout the body.
Human immunodeficiency virus is the causative agent of aids acquired immunodeficiency syndrome, a disease which was first described in the united states in the early 1980s. Pdf hiv life cycle, innate immunity and autophagy in the. Sep 19, 2006 unless the hiv lifecycle is interrupted by treatment, the virus infection spreads throughout the body and results in the destruction of the bodys immune system. However, while the late stages of the retrovirus life cycle, consisting of virus replication and egress, have been partly unraveled, the early steps remain largely enigmatic. Dna detected in nucleus 4h gag shell priming completion in about 10 min buding occurs 15min after. Hiv life cycle, innate immunity, and autophagy in the. To understand each stage in the hiv life cycle, it helps to first imagine what hiv looks like.
The viral rna yellow stringlike structure in core is converted into viral dna red. Adaptations make a power point presentation to explain hiv life cycle and relate it to the viruses ability to evade researchers attempts to engineer an effective vaccine. Youve probably heard of hiv, but do you know how it affects human cells. Decades of research have pieced together the stages of the hiv life cycle, but because the. Those interested in learning more about the basic lifecycle of hiv will find this article useful. The hiv lifecycle hiv, the virus responsible for aids, relies upon the transcription and translation machinery of its host cell. For the virus to transmit, these fluids must come in contact with damaged tissue or mucus membranes of another person, or be directly injected with a needle. Author summary viral pathogens, such as hiv 1, are fully dependent of the cellular machinery to complete the replication cycle. This process, which is carried out in seven steps or stages, is called the hiv life cycle. During adsorption, an envelope glycoprotein on the surface of hiv called gp120 must adsorbs to both a cd4 molecule and then a chemokine. Structure, life cycle, and pathogenecity jonathan richard hughes university of tennessee knoxville. May 14, 2014 this video lecture explains the life cycle of hiv virus and the infection strategy of hiv in causing aids.
This usually occurs within two to four weeks of infection and is. The present work follows the process of infection of the cell with simultaneous measurements of viral replication intermediates together with the concurrent. The roles played by hiv1 gag proteins during the life cycle are numerous and complex, involving not only assembly but also virion maturation after particle release and early postentry steps in virus replication. A capsid containing the viruss genome and proteins then enters the cell. P17 also acts as a viral cytokine, a substance that helps cells communicate and move in a particular direction source. Hiv diagnosis and pathogenesis columbia university. There are seven 7 stages or steps of the hiv virus replication cycle. Helper t cells play a central role in normal immune responses by producing factors that activate virtually. Hiv attacks and destroys the cd4 cells of the immune system. Watch the life cycle of hiv in colorful new detail. Apr 21, 2014 a collection of patient education fact sheets on hiv aids treatments and conditions, in english and spanish. It allows us to identify how the virus makes copies of itself, which in turn allow us to develop ways to block or inhibit. Follow each stage in the hiv life cycle, as hiv attacks a cd4 cell and uses the machinery of the cell to multiply.
Those host proteins that have a role in the replication cycle and are discussed in the text are indicated. Effectively, the virus has now hijacked the host cells own replication system. Authors describe a mechanism though which hiv hijacks the autophagosome to promote replication. The life cycle of hiv and hiv disease december 2011possible benefits of starting at 350500 an increasing number of observational results and early clinical studies suggest lower rates of aids and other healthrelated conditions and death.
While major efforts have been made during the last years to define the molecular mechanisms and cellular targets of vpr, additional work is needed for the complete. Subscribe to our email newsletter to receive updates. Students will learn about the hiv life cycle and in small groups discuss and propose methods to prevent the spread of the infection. Mark cichocki, rn, is an hiv aids nurse educator at the university of michigan health system for more than 20 years. As a result, when the cellular dna is transcribed, so is the viral dna to form an rna. After fusion, the virus releases rna, its genetic material, into the host cell. In order for a person to become infected with hiv, one or more virus particles must enter the body. Hiv replication or hiv life cycle refers to how the hiv virus reproduces itself using the genetic makeup of the host cell human cell. The reproductive cycle of hiv what is the lytic cycle. The main cellular target of hiv is a special class of white blood cells critical to the immune system known as helper t lymphocytes, or helper t cells. The viral protein r vpr of hiv 1 is a small basic protein 14 kda of 96 amino acids, and is well conserved in hiv 1, hiv 2 and siv.
So its important to understand the life cycle of the virus. It contains information on how the virus reproduces, replicates and how this has lead to it being so effective at continuing to evade our efforts to eradicate it. Structure, life cycle, and pathogenecity tennessee research. Nov 18, 2016 the 8 stages of the hepatitis c viral life cycle the earlier youre treated for hepatitis c, the better. However, many recent discoveries have important implications as the field renews hope for solving the problem of eradication and searches for treatments for hand. Viral dynamics in human immunodeficiency virus type 1 infection x. The cycle results in the destruction of the infected cell and its membrane. Phosphorylation of human immunodeficiency virus type 1 capsid protein at serine 16. Hiv life cycle 1 free virus 2 attachment and entry. The gag proteins of hiv1, like those of other retroviruses, are necessary and sufficient for the assembly of viruslike particles. It then takes control of the cells dna, replicates itself inside the cell, and finally releases more hiv into the blood continuing the multiplication process. It is an enveloped virus with a single stranded, positive sense rna genome, which infects humans and is the causative agent of the acquired immunodeficiency syndrome aids 32, 33.
Virus binds to a cd4 molecule and one type of coreceptor either ccr5 or cxcr4. Lecture hiv virus life cycle lecture notes hiv virus life. Jul 01, 2019 hiv attacks and destroys the cd4 cells of the immune system. The present work follows the process of infection of the cell with simultaneous measurements of viral replication intermediates together with the concurrent assessment of. During the course of the thirtyyear epidemic, much has been learned about hiv infection of neuroglia and viral replication in the cns. The infection begins when the envelope env glycoprotein spikes engage the receptor cd4 and the membranespanning coreceptor ccchemokine receptor 5 ccr5 step 1, leading to. Nov 18, 2014 youve probably heard of hiv, but do you know how it affects human cells. Cd4 cells are a type of white blood cell that play a major role in protecting the body from infection. Unless the hiv lifecycle is interrupted by treatment, the virus infection spreads throughout the body and results in the destruction of the bodys immune system. Hiv proteins are shown in red and magenta, hiv rna is in yellow and hiv dna is in yellowgreen. The 8 stages of the hepatitis c viral life cycle the earlier youre treated for hepatitis c, the better. The hiv life cycle and antiretroviral drugs part 1 duration. Human immunodeficiency virus hiv is a member of the lentivirus genus of the retroviridae family. The hiv lifecycle is the story of how a single hiv virus particle infiltrates a cell and uses it to produce new hiv particles this isnt the whole story about hiv, of course.
How hiv infects the body and the lifecycle of hiv avert. Hiv binds to the cd4 receptors on the helper t cells. A collection of patient education fact sheets on hivaids treatments and conditions, in english and spanish. Since its initial discovery, hivaids has risen to become a global pandemic, with over 30 million infected individuals worldwide. By interfering with many distinct cellular pathways all along the virus life cycle, it is now evident that vprs contribution to the overall pathogenesis of hiv1 infection in vivo is likely crucial.
24 784 1220 688 478 164 124 528 629 693 129 1082 1143 1439 580 831 1056 443 1265 1032 815 853 565 1363 1093 1208 203 640 1309 1136 56 703 1397 113 1330 1192 347 489 92 77 156 1069 1013 592