Is gene editing ethical? It depends

One of Matthew Liao's most popular papers proposes that humans could genetically engineer themselves to collectively reduce our species' carbon footprint.

How HIV DNA is blocked from entering the cell nucleus

Multiple components of the nuclear pore complex and nuclear import machinery enable a protein called human myxovirus resistance 2 (MX2) to inhibit HIV-1 infection, according to a study published November 29 in the open-access ...

A better HIV test

Public health officials have a tough choice to make when it comes to screening people for HIV: administer a reliable blood test that can detect infections early on, but that few people will volunteer for, or give people a ...

Mathematically modeling HIV drug pharmacodynamics

37 million people around the world today live with Human Immunodeficiency Virus (HIV), which is responsible for roughly 1.1 million deaths caused by AIDS-related conditions.

Storming the cellular barricades to fight fungi

Yale scientists have developed a new class of small molecules that attack fungal infections by clinging to the cell wall of harmful fungi and recruiting a swarm of antibodies to join the fight.

Restricting HIV-1 infection

The HIV-1 capsid protein (CA) interacts with viral factors that support infection and host factors that restrict it. The host protein cyclophilin A (CypA) binds to CA and enhances the action of host restriction factors that ...

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HIV

Human immunodeficiency virus (HIV) is a lentivirus (a member of the retrovirus family) that causes acquired immunodeficiency syndrome (AIDS), a condition in humans in which the immune system begins to fail, leading to life-threatening opportunistic infections. Infection with HIV occurs by the transfer of blood, semen, vaginal fluid, pre-ejaculate, or breast milk. Within these bodily fluids, HIV is present as both free virus particles and virus within infected immune cells. The four major routes of transmission are unsafe sex, contaminated needles, breast milk, and transmission from an infected mother to her baby at birth (Vertical transmission). Screening of blood products for HIV has largely eliminated transmission through blood transfusions or infected blood products in the developed world.

HIV infection in humans is now pandemic. From 1981 to 2006, AIDS killed more than 25 million people. HIV infects about 0.6 percent of the world's population. In 2005 alone, AIDS claimed an estimated 2.4–3.3 million lives, of which more than 570,000 were children. A third of these deaths are occurring in sub-Saharan Africa, retarding economic growth and increasing poverty. According to current estimates, HIV is set to infect 90 million people in Africa, resulting in a minimum estimate of 18 million orphans. Antiretroviral treatment reduces both the mortality and the morbidity of HIV infection, but routine access to antiretroviral medication is not available in all countries.

HIV primarily infects vital cells in the human immune system such as helper T cells (specifically CD4+ T cells), macrophages, and 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 apoptosis in infected cells; and thirdly, killing of infected CD4+ T cells by CD8 cytotoxic lymphocytes that recognize infected cells. When CD4+ T cell numbers decline below a critical level, cell-mediated immunity is lost, and the body becomes progressively more susceptible to opportunistic infections.

Eventually most HIV-infected individuals develop AIDS. These individuals mostly die from opportunistic infections or malignancies associated with the progressive failure of the immune system. Without treatment, about 9 out of every 10 persons with HIV will progress to AIDS after 10–15 years. Many progress much sooner. Treatment with anti-retrovirals increases the life expectancy of people infected with HIV. Even after HIV has progressed to diagnosable AIDS, the average survival time with antiretroviral therapy (as of 2005) is estimated to be more than 5 years. Without antiretroviral therapy, death normally occurs within a year.

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