Question

Gamma interferon, synthesized by \(T\) lymphocytes, stimulates the humoral immune system to fight viral infections. Which of the following findings would provide evidence that the humoral immune system has been recruited? A. Increased phagocytosis of virally infected cells B. Increased inflammation at the site of viral entry C. Increased concentration of B lymphocytes at the site of viral entry D. Increased concentration of immunoglobulins at the site of viral entry

Short answer

D: Increased concentration of immunoglobulins at the site of viral entry

Step-by-step solution

Identify the Humoral Immune System

The humoral immune system involves the production of antibodies by B lymphocytes to neutralize pathogens.

Review the Findings Provided

Consider each option and relate it to the activity of the humoral immune system: A. Involves phagocytosis, which is part of the innate immune response.B. Inflammation is an immune response but not specifically related to the humoral immune system.C. Increased B lymphocytes suggest involvement of the humoral system but not direct evidence of antibody action.D. Increased immunoglobulins (antibodies) directly relate to the humoral immune response.

Evaluate the Correct Answer

Option D indicates an increase in immunoglobulins at the site of entry, which directly provides evidence that the humoral immune system has been recruited.

Key concepts

gamma interferon

Gamma interferon is a crucial cytokine in our immune system. It is primarily produced by T lymphocytes, specifically those known as Th1 cells. This molecule plays an essential role in both the innate and adaptive immune responses to viral infections.

When gamma interferon is released, it activates several immune mechanisms. It promotes the activity of macrophages and enhances the ability of B lymphocytes to produce antibodies. This ensures that pathogens are effectively neutralized and eliminated from the body.

Therefore, gamma interferon serves as a critical mediator, facilitating communication between various cells of the immune system, and ensuring a coordinated response against viral pathogens.

T lymphocytes

T lymphocytes, or T cells, are a type of white blood cell central to the adaptive immune system. They originate from the thymus and play a critical role in identifying and destroying infected cells. There are various subsets of T lymphocytes, each with specific functions:

• Helper T cells (Th cells): These assist other immune cells by releasing cytokines like gamma interferon.
• Cytotoxic T cells (CTLs): They recognize and kill virus-infected cells directly.
• Regulatory T cells (Tregs): These maintain immune system balance and prevent autoimmunity.

When a T lymphocyte recognizes a viral antigen presented by an infected cell, it gets activated and proliferates. This proliferation helps in efficiently combating the infection. Additionally, T lymphocytes help in the activation of B lymphocytes, which are responsible for antibody production.

immunoglobulins

Immunoglobulins, also known as antibodies, are specialized proteins that play a key role in the humoral immune response. They are produced by B lymphocytes and are essential for identifying and neutralizing pathogens such as viruses and bacteria. There are several types of immunoglobulins, each with specific functions:

• IgG: The most common antibody, present in all body fluids, and vital for fighting bacterial and viral infections.
• IgA: Found in mucous membranes, saliva, and tears, protecting the body's entry points.
• IgM: The first antibody produced in response to infection.
• IgE: Associated with allergic reactions and parasitic infections.
• IgD: Functions mainly as a receptor on B cells.

Increased levels of immunoglobulins at the site of infection indicate an active humoral immune response. This means the body is producing antibodies to neutralize and eliminate the offending pathogen effectively.

B lymphocytes

B lymphocytes, or B cells, are a type of white blood cell responsible for producing antibodies as part of the humoral immune response. They mature in the bone marrow and play a pivotal role in detecting and fighting off pathogens.

When a B lymphocyte encounters its specific antigen (a substance that triggers an immune response), it binds to it and becomes activated. Activated B cells differentiate into plasma cells, which produce and secrete large quantities of antibodies. These antibodies then target and neutralize the pathogen.

B lymphocytes also serve as memory cells, retaining information about past infections. This memory enables a quicker and more efficient response if the same pathogen invades the body again in the future.

Increased concentration of B lymphocytes at the site of viral entry suggests that the humoral immune system is being mobilized to produce antibodies to fight off the infection.