Take-Away:

Vaccinations create long-term immunity to specific pathogens. 

• A vaccine is a weakened pathogen. 

• When you get a vaccine, your white blood cells begin producing antibodies to it. Special white blood cells (memory cells) remember the antigen on the vaccine pathogen so next time you get the actual pathogen, you will already have a defense to it. 

Since its discovery, how many people do you think have died directly due to HIV? 

(best guess)

HIV and AIDS

Human Immunodeficiency Virus, commonly called HIV, is a virus that attacks the immune system. The immune system is the body’s defense system that helps protect against disease-causing organisms such as viruses and bacteria. HIV specifically targets certain white blood cells called helper T cells, also known as CD4 cells. These cells play an important role in coordinating the immune response by helping other immune cells recognize and attack pathogens. When HIV enters the body, it begins infecting and damaging these important immune cells.

HIV spreads through certain body fluids, including blood, semen, and breast milk. The virus can be transmitted through unprotected sexual contact, sharing contaminated needles, from mother to baby during pregnancy or birth, and through breastfeeding. HIV cannot spread through casual contact such as hugging, shaking hands, sharing food, or using the same bathroom. Once the virus enters the bloodstream, it seeks out helper T cells and enters them.

After HIV enters a helper T cell, it uses the cell’s machinery to reproduce. The virus inserts its genetic material into the DNA of the host cell. This process allows the infected cell to produce many copies of the virus. As more viruses are produced, they leave the cell and infect other helper T cells. Over time, this process destroys many of these important immune cells and weakens the body’s ability to fight infections.

If HIV continues to damage the immune system without treatment, the infection can progress to Acquired Immunodeficiency Syndrome, or AIDS. AIDS is the most advanced stage of HIV infection. At this stage, the immune system has been severely weakened, and the body becomes vulnerable to infections and diseases that a healthy immune system would normally be able to fight off. These infections are often called opportunistic infections because they take advantage of the weakened immune system.

Although there is currently no cure for HIV, modern medical treatments can control the virus. These treatments are called antiretroviral therapies, or ART. ART medications work by blocking different stages of the virus’s life cycle, which reduces the amount of virus in the body. When people with HIV take these medications regularly, the amount of virus in their blood can become extremely low, allowing the immune system to stay stronger.

Scientists continue to research HIV in order to develop better treatments and potential vaccines. Education, testing, and access to treatment have greatly improved the lives of people living with HIV. With proper medical care, many individuals with HIV are able to live long and healthy lives while keeping the virus under control.

Make six questions, three short response

Questions Based on the HIV/AIDS Article

Multiple Choice

1. Which type of cell does HIV mainly infect and damage?
   (1) Red blood cells
   (2) Helper T cells (CD4 cells)
   (3) Nerve cells
   (4) Muscle cells
   
   

2. HIV spreads through which of the following body fluids?
   (1) Sweat and saliva
   (2) Tears and sweat
   (3) Blood and semen
   (4) Saliva and tears
   
   

3. What is the main purpose of antiretroviral therapy (ART)?
   (1) To completely remove HIV from the body
   (2) To destroy all white blood cells in the body
   (3) To block stages of the virus’s life cycle and reduce the amount of virus in the body
   (4) To prevent the body from producing antibodies
   
   

Short Response

4. Explain how HIV reproduces inside a helper T cell. In your answer, include what happens to the virus’s genetic material.
   
   
   

5. Explain why people with AIDS are more likely to develop infections.

Key Concept: 

The Human Immunodeficiency Virus weakens the immune systems ability to fight pathogens. Overtime this leads to Acquired Immunodeficiency Syndrome which is the last stage of HIV infection. When someone has AIDS, their immune system is so weak any infection can cause death. 

Autoimmune Diseases

The immune system normally protects the body from harmful pathogens such as bacteria and viruses. Immune cells recognize these harmful invaders by detecting antigens, which are molecules found on the surface of pathogens. Once these antigens are recognized as foreign, the immune system produces antibodies and activates white blood cells to attack and destroy the pathogen.

Sometimes, however, the immune system makes a mistake. In autoimmune diseases, the immune system incorrectly identifies the body’s own cells as foreign. The immune system may produce antibodies or activate immune cells that attack healthy tissues. Instead of protecting the body, the immune response begins damaging its own cells and organs.

There are many different types of autoimmune diseases, and each affects different parts of the body. For example, in type 1 diabetes, the immune system attacks the insulin-producing cells of the pancreas. In multiple sclerosis, immune cells damage the protective covering around nerve cells. In rheumatoid arthritis, the immune system attacks tissues in the joints, causing pain and inflammation.

Scientists believe autoimmune diseases may be caused by a combination of genetic and environmental factors. Certain infections, environmental triggers, or changes in the immune system may cause the body to lose its ability to recognize its own cells as “self.” When this recognition fails, the immune system may begin attacking healthy tissues.

Although most autoimmune diseases cannot be cured, many treatments help control the immune response. Some medications work by reducing inflammation, while others suppress parts of the immune system to prevent further damage to the body’s tissues. Early diagnosis and treatment can help people manage symptoms and maintain a better quality of life.

Exit Ticket

In your own words, describe what an autoimmune disease is. In your answer, include:
• how the immune system normally protects the body
• what mistake the immune system makes during an autoimmune disease
• how this mistake can affect the body’s tissues or organs.