Thursday, May 19, 2022

What Cells Does Hiv Attack

How Do People Get Hiv

How HIV kills so many CD4 T cells | Infectious diseases | NCLEX-RN | Khan Academy

HIV spreads when infected blood or body fluids enter the body. This can happen:

HIV also can pass from mother to child during pregnancy, childbirth, or breastfeeding.

HIV is NOT spread through:

  • pee, poop, spit, throw-up, or sweat
  • coughing or sneezing
  • sharing eating utensils or drinking glasses

What Is Hiv What Is Aids

HIV is a virus that attacks the immune system, the bodys natural defense system. Without a strong immune system, the body has trouble fighting off disease. Both the virus and the infection it causes are called HIV.

White blood cells are an important part of the immune system. HIV invades and destroys certain white blood cells called CD4+ cells. If too many CD4+ cells are destroyed, the body can no longer defend itself against infection.

The last stage of HIV infection is AIDS . People with AIDS have a low number of CD4+ cells and get infections or cancers that rarely occur in healthy people. These can be deadly.

Having HIV does not mean you have AIDS. Even without treatment, it takes a long time for HIV to progress to AIDSusually 10 to 12 years. If HIV is diagnosed before it becomes AIDS, medicines can slow or stop the damage to the immune system. With treatment, many people with HIV are able to live long and active lives.

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Ctl Evolution Following Acute Infection

Although a narrowly directed immune response is found at the time of maximal decline in peak viremia, responses subsequently broaden, such that during chronic infection the average person targets a median of 14 epitopes simultaneously , and given that these studies were performed with a reference set of peptides rather than autologous peptides, the actual number may be 20%30% higher . Immunization studies in animal models indicate that the CD8+ T-cell compartment has enormous expansion capacity, without affecting the size of the naïve CD4+, CD8+, or B-cell populations, and while preserving memory CD8+ T-cell populations to other pathogens . HIV-specific CD8+ T-cell responses remain detectable throughout the course of disease, and are actually broader and higher in persons with progressive infection than in those with controlled infection .

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What Is A Cd4 Count

A CD4 count is a test that measures the number of CD4 cells in your blood. CD4 cells, also known as T cells, are white blood cells that fight infection and play an important role in your immune system. A CD4 count is used to check the health of the immune system in people infected with HIV .

HIV attacks and destroys CD4 cells. If too many CD4 cells are lost, your immune system will have trouble fighting off infections. A CD4 count can help your health care provider find out if you are at risk for serious complications from HIV. The test can also check to see how well HIV medicines are working.

Other names: CD4 lymphocyte count, CD4+ count, T4 count, T-helper cell count, CD4 percent

Hiv Effects On The Immune System

The role of brain cells in spreading HIV

Your immune system has many types of white blood cells that fight infection. HIV gets inside a kind called CD4 cells and makes copies of itself. The virus kills the cell, and the new viruses go off to find more.

Your body responds by making more CD4 cells, but after a while, it canât keep up with the virus. This makes your immune system weak. Youâre more likely to get sick, even from common germs. Infections last longer, are more severe, and might come back more often.

If you follow your doctorâs directions with ART, it knocks out HIV, stopping it from infecting more CD4 cells and from weakening your immune system.

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Progression From Hiv To Aids

In the final stage of HIV, a patients T-cell count falls as viral load increases the immune system becomes severely compromised. When the patient is diagnosed with a stage-4 HIV-related condition such as tuberculosis or cancer or pneumonia, the virus has made its progression to AIDS, Acquired Immunodeficiency Syndrome. Many of the symptoms and sickness at this point may be from opportunistic infections and not from AIDS itself. Once the virus has progressed to AIDS, the body is more likely to fail, though the time left to a patient ranges anywhere from just a few months to many years.

To learn more about what happens when HIV becomes AIDS, watch the video below, courtesy of YouTube:

Hiv Prevention And Treatment

If a person is HIV positive, there are treatment options to keep them healthy and prevent them from transmitting it. Thankfully, with proper treatment for HIV, people can live long, healthy lives by keeping their viral load under control in Stage 2.

HIV treatment drugs suppress a persons viral load or the number of HIV cells in the body. Doctors will monitor the cell count and when it falls an undetectable range, they are considered to be non-transmittable.

Scientific research has proven that a person cannot transmit HIV to another partner if their viral load is undetectable. This is commonly which stands for undetectable = untransmittable.

Of course, the best way to stop HIV transmission is to understand how to protect yourself and others from exposure. Using condoms and avoiding sharing needles is effective but taking PrEP can provide the greatest protection even if you are accidentally exposed.

PrEP is a medication prescribed by a doctor which can lower the risk of HIV transmission significantly. This drug stops HIV from being able to reproduce in the body. So, it can be taken before exposure and stop HIV transmission.

If a person has knowingly been exposed to HIV and is not currently on PrEP or has missed numerous doses, then they will be prescribed PEP. This is a medication regimen of HIV prevention drugs that must be administered with 72 hours of exposure. This can stop HIV from reproducing and diminish a persons viral load.

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How Is Hiv Treated

Treatments for HIV typically involve antiretroviral therapy. This isnt a specific regimen, but instead a combination of three or four drugs. The U.S. Food and Drug Administration has currently approved nearly 50 different medications to treat HIV.

Antiretroviral therapy works to prevent the virus from copying itself. This maintains immunity levels while slowing the progression of HIV.

Before prescribing medication, a healthcare provider will take the following factors into consideration:

  • a persons health history
  • the levels of the virus in the blood

HIV doesnt cause a lot of outward or noticeable symptoms until the disease has progressed. For this reason, its important to understand how HIV is transmitted and the ways to prevent transmission.

HIV can be transmitted by:

  • having sex, including oral, vaginal, and anal sex
  • sharing needles, including tattoo needles, needles used for body piercing, and needles used for injecting drugs
  • coming into contact with body fluids, such as semen, vaginal fluid, blood, and breast milk

HIV is not transmitted by:

  • breathing the same air as a person living with HIV
  • getting bitten by a mosquito or other biting insect
  • hugging, holding hands with, kissing, or touching a person living with HIV
  • touching a door handle or toilet seat thats been used by an HIV-positive person

Keeping this in mind, some of the ways a person can prevent HIV include:

Symptoms can take years to appear, which is why its so important to get tested regularly.

How To Raise Or Lower White Blood Cell Count

Immunology wars: The battle with HIV

Whether or not a person needs to alter their white blood cell count will depend on the diagnosis.

If they have a medical condition that affects the number of white blood cells in their body, they should talk to a doctor about the goals for their white blood cell count, depending on their current treatment plan.

A person can lower their white blood cell count by taking medications such as hydroxyurea or undergoing leukapheresis, which is a procedure that uses a machine to filter the blood.

If a persons white blood cell count is low due to cancer treatments such as chemotherapy, a doctor may recommend avoiding foods that contain bacteria. This may help prevent infections.

A person can also take colony-stimulating factors. These may help prevent infection and increase the number of white blood cells in the body.

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Hiv Takes Control Of T Cells

Once inside the cell, the capsid dissolves, liberating the viral RNA and the reverse transcriptase. Now, in order to infect the cell, the viral RNA needs to travel into the T cell’s nucleus . However, for that to happen, an important transformation needs to take place.

Normally, the T cell’s nucleus communicates with the rest of the cell by transforming DNA into RNA and sending it out of the nucleus. The genetic material’s passport to leave the nucleus is to be transformed into single-stranded RNA. In the same fashion, the passport to enter the nucleus is to be transformed into double-stranded DNA.

Viral RNA needs to become DNA in order to start the replication process. Reverse transcriptase allows the RNA to borrow material from the cell and to “write backwards” a chain of viral DNA.

HIV is considered a retrovirus because of its capacity to transform RNA into DNA, reversing the natural process that takes place in cells. This is accomplished by the reverse transcriptase. Retroviruses are a special family of viruses to which only a few known viruses belong .

The Science Of Hiv And Aids

Key Points

  • HIV stands for Human Immunodeficiency Virus, a pathogen that works by attacking the human immune system.
  • HIV specifically targets CD4 cells, the bodys principal defenders against infection, using them to make copies of themselves.
  • Antiretroviral drugs target specific stages of the HIV lifecycle to stop HIV from replicating.

Explore this page to find out more about , , and .

HIV stands for Human Immunodeficiency Virus, a pathogen that works by attacking the human immune system. It belongs to a class of viruses called retroviruses and more specifically, a subgroup called lentiviruses, or viruses that cause disease slowly. 1

HIV cannot replicate on its own, so in order to make new copies of itself, it must infect cells of the human immune system, called CD4 cells. CD4 cells are white blood cells that play a central role in responding to infections in the body. 2

Over time, CD4 cells are killed by HIV and the bodys ability to recognise and fight some types of infection begins to decline. If HIV is not controlled by treatment, the loss of CD4 cells leads to the development of serious illnesses, or opportunistic infections. In people with normal CD4 cell levels, these infections would be recognised and cleared by the immune system. 3

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Hiv And The Immune System

Human Immunodeficiency Virus is a virus that attacks and destroys the bodys T lymphocytes. The reduction in the number of T lymphocytes in the body due to HIV can then lead to the development of Acquired Immune Deficiency Syndrome .

Individuals with AIDS have a weakened immune system and so are more vulnerable to opportunistic infections.

Without immunity, infection by microorganisms, such as those that cause tuberculosis

Ctl Responses In Acute Infection

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Despite the narrowness of the acute phase CD8+ T-cell response, it is associated with a dramatic decline in initial viremia, suggesting that these early, presumably narrowly directed responses are at least partially effective. Although functional studies of early CTL responses are few , evidence of CD8+ T-cell efficacy is suggested by detailed analysis of viral genomes during these early phases of infection, and by modeling studies. 80% of acute infections are established by a single founder virus, which first begins to diversify at around the time of peak infection . By single genome amplification one can detect viral evolution at sites of CTL pressure as early as peak viremia , clear indication that there is effective pressure being applied because it can lead to a wholesale turnover in the replicating virus population. This has been modeled, suggesting that 15%35% of infected cells can be killed by CTLs of a single specificity per day in vivo during acute infection . This CD8+ T-cell-mediated immune pressure is also apparent in population studies, which have shown clear HLA-associated signature mutations following acute infection , persisting in the chronic phase of infection , and transmission and reversion of CTL escape variants .

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Can Hiv Be Prevented

To reduce the risk of getting HIV, people who are sexually active should:

  • use a condom every time they have sex
  • get tested for HIV and make sure all partners do too
  • reduce their number of sexual partners
  • get tested and treated for STDs having an STD increases the risk of HIV infection
  • consider taking a medicine every day if they are at very high risk of getting infected

For everyone:

  • Do not inject drugs or share any kind of needle.
  • Do not share razors or other personal objects that may touch blood.
  • Do not touch anyone else’s blood from a cut or sore.

Hiv And Aids: Causes Symptoms Treatments And Future Prospects

Everything you need to know about HIV and AIDS including common symptoms and where to get tested.

HIV is a virus that attacks the bodys immune system and is most commonly caught by having unprotected sex, sharing injection needles, infected blood products or in extremely rare cases the infection of a baby by its mother.

There are still a huge number of misconceptions around HIV and AIDS, so Dr Roger Henderson sets the facts straight:

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Why Is Hiv So Evasive What Is The Hiv Reservoir

Although HIV can be controlled by antiretroviral therapy, it cannot be eliminated from the body. This is because HIV evades the normal immune system mechanisms for getting rid of cells infected by viruses.

HIV integrates itself into the DNA of human immune system cells and only replicates when the cell is stimulated to respond to an infection. These cells are called latently-infected cells. These cells are not recognised as infected by the immune system and killed off, allowing them to persist for as long as the cell lives.17

Some of the cells infected by HIV are very long-lasting memory T-cells. Reservoirs of latently- infected cells become established in the lymph nodes, the spleen and the gut. HIV also infects cells in the brain, but it is unclear if HIV can pass from the brain to other parts of the body. HIV may also persist for many years in macrophages immune cells found largely in tissues and in dendritic cells, which recognise infectious agents and alert other immune cells to remove them.

Latently-infected cells can proliferate without being activated and HIV may also pass from cell to cell within tissues in the gut and other reservoirs. 18 This means they evade the immune system and are not suppressed by antiretroviral drugs before infecting other cells.

Inhibition Of Hivs Entry

HIV destroys helper T-cells | Biology | Anatomy | Immunology

The entry of HIVs is currently understood to be essentially a three-step process consisting of attachment, chemokine co-receptor interaction, and fusion. Therefore, specific areas of interest to inhibit HIVs entry include blocking gp120 binding to CD4 cell receptors , blocking the binding sites of co-receptors such as CCR5 and CXCR4 , and disrupting the fusion process .

The fusion inhibitor, enfuvirtide , a 36-amino acid peptide being developed jointly by Trimeris and Roche, is in the most advanced stage of clinical development. HIV fusion with CD4 cells is a complex process, and not very well understood, and involves a conformational change in the HIV envelope gp120/gp41, leading to an interaction between gp41 that lead to intimate proximity between the HIV envelope and the cell membrane, allowing fusion to occur. Enfuvirtide is active against both CCR-5- and CXCR4-using viruses and are synergistic with CCR5 and CXCR4 antagonists.

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Innate Immune Response To Hiv

Innate immune cells are the first line of defence which HIV encounters upon entry to the body.

Macrophages. Tissue macrophages are one of the target cells for HIV. These macrophages harbour the virus and are known to be the source of viral proteins. However, the infected macrophages are shown to lose their ability to ingest and kill foreign microbes and present antigen to T cells. This could have a major contribution in overall immune dysfunction caused by HIV infection.

Dendritic cells . DCs are large cells with dendritic cytoplasmic extensions. These cells present processed antigens to T lymphocytes in lymph nodes. Epidermal DCs, expressing CD1a and Birbeck granules, are probably among the first immune cells to combat HIV at the mucosal surfaces. These cells transport HIV from the site of infection to lymphoid tissue. The follicular DCs, found in lymphoid tissue, are also key antigen-presenting cells that trap and present antigens on their cell surfaces. In the lymph node follicles, DCs provide signals for the activation of B lymphocytes.

What Does A Self

Self-confidence is an attitude about your skills and abilities. It means you accept and trust yourself and have a sense of control in your life. You know your strengths and weakness well, and have a positive view of yourself. You set realistic expectations and goals, communicate assertively, and can handle criticism.

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How Can People With Hiv Reduce Their Risk Of Kidney Disease

People with HIV can take the following steps to reduce their risk of kidney disease:

  • Take HIV medicines every day to keep HIV under control.
  • Eat a healthy diet that includes fresh fruits, fresh or frozen vegetables, whole grains, and low-fat or fat-free dairy products. Cut back on foods high in salt and sugar.
  • Be physically active for 30 minutes or more on most days.
  • Keep all medical appointments. During medical visits, talk to a health care provider about the risk of kidney disease.

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