Question

If a virus, such as HIV, destroys the body's T-lymphocytes, to which type of diseases would the patient be most susceptible? A. Viral infections B. Bacterial infections C. Autoimmune diseases D. Immunoglobulin deficiencies

Short answer

A. Viral infections

Step-by-step solution

Identify the role of T-lymphocytes

T-lymphocytes, also known as T-cells, are a type of white blood cell that play a crucial role in the immune response. They help in recognizing and destroying infected cells and activating other immune cells.

Understand the impact of T-lymphocyte destruction

When T-lymphocytes are destroyed, the body's ability to recognize and combat infections becomes compromised. This weakens the immune system.

Analyze the types of diseases listed

Evaluate which type of diseases a weak immune system would struggle to combat. These are likely to be those that require a strong cell-mediated response, which is primarily the function of T-lymphocytes.

Match the immune function to disease types

A compromised cell-mediated immune response, due to the destruction of T-lymphocytes, would result in increased susceptibility to infections that the body relies on T-cells to fight. Specifically, viral infections typically require a strong T-cell response for effective defense.

Conclusion

Based on the role of T-lymphocytes and their destruction, patients would most likely be more susceptible to viral infections.

Key concepts

T-lymphocytes

T-lymphocytes, or T-cells, are a type of white blood cell that play a vital role in the immune system. They are part of the adaptive immune response, meaning they adapt specifically to combat different pathogens. T-cells help recognize and destroy cells that have been infected by viruses or other pathogens. They also assist in activating other immune responses.

There are different types of T-cells such as:

• Helper T-cells (CD4+ cells): These cells aid in activating and directing other immune cells, including T-cells and B-cells.
• Killer T-cells (cytotoxic T-cells or CD8+ cells): These cells directly attack and kill infected cells, especially those infected by viruses.
• Regulatory T-cells: These prevent immune responses from becoming too strong and damaging the body’s own tissues.

In summary, T-lymphocytes are crucial for defending against infections by directly eliminating infected cells and coordinating other parts of the immune system.

Viral Infections

Viral infections occur when viruses invade the body and take over cells to reproduce. They can affect many parts of the body, including the respiratory system, liver, and other areas. Examples of viral infections include the common cold, HIV, and influenza.

The body relies heavily on T-lymphocytes to combat viral infections. When the T-cells identify cells that have been infected, they destroy these cells to prevent the virus from spreading. T-cells also produce signals to activate other parts of the immune system to join the fight.

Without T-lymphocytes, the body struggles to control viral infections, making individuals more susceptible to severe and prolonged illnesses. In the case of diseases like HIV, which specifically targets T-cells, the body becomes significantly weakened against viral challenges.

Immune Response

The immune response is the body's defense mechanism against pathogens like viruses, bacteria, and other harmful agents. It involves both the innate (non-specific) and adaptive (specific) immune systems.

T-lymphocytes are a crucial component of the adaptive immune response. Here’s how the process works:

• Pathogen Recognition: When a pathogen invades the body, it is initially confronted by innate immune cells which provide the first line of defense.
• Antigen Presentation: Certain cells, like dendritic cells, present pieces of the pathogen (antigens) on their surfaces to T-cells.
• T-cell Activation: T-cells recognize these antigens and get activated. Helper T-cells then recruit other immune cells, while cytotoxic T-cells destroy infected cells.
• Elimination: The immune cells work together to eliminate the pathogen from the body.

An efficient immune response depends on the proper functioning of the T-lymphocytes. Without these cells, the body has a hard time activating and coordinating an effective defense, especially against viral infections. This impairment can lead to more frequent and severe infections.