What you need to know about HIV/AIDs

AIDS- the result of infection with the human immunodeficiency virus (HIV), is an incurable and deadly STD.
AIDS- attacks the body’s immune system, leaving victims unable to fight off even the mildest infections.
While HIV can be transmitted by other means, sexual contact is the most common means of transmission.
Women who are infected with HIV can pass the virus to their infants during pregnancy, childbirth or, less frequently, in breast milk.
Treatment options -for people infected with HIV include protease inhibitors, which can markedly increase survival.

Becky Kuhn, M.D.,
co-founder of Global Lifeworks

What is Human immunodeficiency Virus?

(HIV/AIDs)

Infectious agent that causes acquired immunodeficiency syndrome (AIDS), a disease that leaves a person vulnerable to life-threatening infections. Scientists have identified two types of this virus.

HIV-1 Is the primary cause of AIDS worldwide.

HIV-2 is found mostly in West Africa.

HIV belongs to the retrovirus family of viruses.

HIV transmission

Occurs when a person is exposed to body fluids infected with the virus;

a.) blood

b.) semen

c.) vaginal secretions

d.) breast milk

The primary modes of HIV transmission are;

(1) sexual relations with an infected person

(2) sharing hypodermic needles or accidental pricking by a needle contaminated with infected blood.

(3) transfer of the virus from an infected mother to her baby during pregnancy, childbirth, or through breast-feeding.

When HIV enters the bodyIt infects lymphocytes, white blood cells of the immune system.

The virus commandeers the genetic material of the host cell, instructing the cell to replicate more viruses.

The newly formed viruses break free from the host, destroying the cell in the process.

The new viruses go on to infect and destroy other lymphocytes.

Over a period that may last from a few months to up to 15 years.

HIV may destroy enough lymphocytes that the immune system becomes unable to function properly.

An infected person develops multiple life-threatening illnesses from infections that normally do not cause illnesses in people with a healthy immune system.

Some people who have HIV infection may not develop any of the clinical illnesses that define the full-blown disease of AIDS for ten years or more.

Doctors prefer to use the term AIDS for cases where a person has reached the final, life-threatening stage of HIV infection.

What are the Immune system components?

THE IMMUNE SYSTEMThe ability of the immune system to mount a response to disease is dependent on many complex interactions between the components of the immune system and the antigens on the invading pathogens, or disease-causing agents.

A Macrophages
White blood cells are the mainstay of the immune system.
Some white blood cells, known as macrophages.
play a function in innate immunity by surrounding.
ingesting.
and destroying invading bacteria and other foreign organisms in a process called phagocytosis (literally, “cell eating”).
which is part of the inflammatory reaction.

Macrophages also play an important role in adaptive immunity in that they attach to invading antigens and deliver them to be destroyed by other components of the adaptive immune system.

B Lymphocytes
Lymphocytes are specialized white blood cells whose function is to identify and destroy invading antigens.
All lymphocytes begin as “stem cells” in the bone marrow, the soft tissue that fills most bone cavities, but they mature in two different places.
Some lymphocytes mature in the bone marrow and are called B lymphocytes. B lymphocytes, or B cells, make antibodies, which circulate through the blood and other body fluids, binding to antigens and helping to destroy them in humoral immune responses.
Other lymphocytes, called T lymphocytes, or T cells, mature in the thymus, a small glandular organ located behind the breastbone.
Some T lymphocytes, called cytotoxic (cell-poisoning) or killer T lymphocytes, generate cell-mediated immune responses, directly destroying cells that have specific antigens on their surface that are recognized by the killer T cells.
Helper T lymphocytes, a second kind of T lymphocyte, regulate the immune system by controlling the strength and quality of all immune responses.
Most contact between antigens and lymphocytes occurs in the lymphoid organs—the lymph nodes, spleen, and tonsils, as well as specialized areas of the intestine and lungs.
Mature lymphocytes constantly travel through the blood to the lymphoid organs and then back to the blood again.
This recirculation ensures that the body is continuously monitored for invading substances.

C Antigen Receptors
One of the characteristics of adaptive immunity is that it is specific:Each response is tailored to a specific type of invading antigen. Each lymphocyte, as it matures, makes an antigen receptor—that is, a specific structure on its surface that can bind with a matching structure on the antigen like a lock and key.
Although lymphocytes can make billions of different kinds of antigen receptors, each individual lymphocyte makes only one kind.
When an antigen enters the body, it activates only the lymphocytes whose receptors match up with it.

D Antigen-Presenting Cells
When an antigen enters a body cell, certain transport molecules within the cell attach themselves to the antigen and transport it to the surface of the cell, where they “present” the antigen to T lymphocytes.
These transport molecules are made by a group of genes called the major histocompatibility complex (MHC) and are therefore known as MHC molecules.
Some MHC molecules, called class I MHC molecules, present antigens to killer T cells; other MHC molecules, called class II MHC molecules, present antigens to helper T cells.

Retrovirus structure

Retrovirus StructureOn average, retroviruses are about 90 nanometers (nm, about 0.000004 in) across, which means they are so small that they can only be seen with an electron microscope.

Retroviruses consist of a flexible outer membrane called the envelope that surrounds a protein case known as the capsid.The envelope is studded with glycoproteins, chemical receptors that enable the virus to lock on to target cells.The capsid’s hollow interior contains two identical strands of RNA.

These RNA strands make up the virus’s genetic program and store all the instructions needed to replicate the virus once it has infected a host cell.Retroviruses also contain molecules of an enzyme called reverse transcriptase.When a virus infects a cell, reverse transcriptase copies the genetic instructions in the virus’s RNA and uses it to build complementary strands of DNA.

In common with most viruses, retroviruses are highly selective about the hosts that they infect. For instance, HIV only causes disease in human cells, not the cells of other types of animals.Also like most viruses, retroviruses show no signs of life when they are isolated from living cells. Many retroviruses, including HIV, are relatively fragile.

Their ability to infect cells lessens after prolonged exposure to the environment outside a host cell.When retroviruses do infect a host cell, their mode of replication leads to frequent mutations—changes in the genetic makeup of viral offspring.These mutations enable viruses to evolve at a rapid rate.

Genetic mutation is one of many reasons why retroviral infections are difficult to treat—medicines developed to combat one retrovirus with a specific genetic makeup are not effective against mutated offspring of that retrovirus.