Question

The remaining questions in this section relate to the following case: Melissa is a 15-year-old high school student. Over the last week, she had been feeling tired and found it difficult to stay awake in class. By the time the weekend had arrived, she developed a sore throat that made it difficult to eat and even drink. Melissa was too tired to get out of bed, and she said her head ached. On Monday morning, her mother took her to her doctor. Upon completing the physical exam, she told Melissa the lymph nodes were enlarged in her neck and she had a fever. She ordered blood tests confirming Melissa had mononucleosis, a viral infection requiring much bed rest.

What kind of immunity will be activated primarily? (1)




Where in the body will the effector cells become activated? (1)




List the steps needed for the effector cells to become activated, with focus on the main signals, and including the receptors and key interleukins used. (6)

How will the infected cells in Melissa’s neck and body be destroyed?

Answer 1

• Mononucleosis is a viral infection caused by Epstein-Barr virus. This virus primarily elicit innate immunity. This virus persist in large population. However, only a small number develop the infection. The primary immune response against the virus is innate immunity that inhibits the replication of virus in the body.
• The CD8⁺ T cells will act as the effector cells and they will be activated and present in the peripheral blood.
• The CD8+ activation in the peripheral blood and the enlargement of the lymph nodes is the common symptom of the Mononucleosis. CD8 + T cell lymphocytosis that are the effector cells are seen with EBV. They are composed of a wide range of particularities of T cell receptors. A large number of these cells are specific to the epitopes of EBV. In comparison, the mononucleosis caused by MHV-68 is governed by oligoclonal Vβ4 + CD8 + T cells. These cells are not reactive to MHV-68 epitopes. This population expansion is drastic with the MHV-68 and the rates reaches up to 60 per cent of the peripheral amount of CD8 + T cells. Evidence from the literature suggests that expansion of Vβ4 + CD8 + T cells does not require a conventional presentation of MHC class 1 antigen. Research have indicated that IL-2 signaling is prominent in the case of CD8+ T cells differentiation and expansion. Moreover, they are also important for the maintenance, expansion and recall of the CD8+ T cell responses.
• The EBV-specific CD4+ and CD8+ memory T cells can act on the infected neck cells of Melissa and they can destroy these infected cells before completing their viral replication. Since mononucleosis is a viral infection so antibiotics are not effective so Melissa require proper bed rest , enough of water and primary pain relievers to cure her condition.