Question

The adaptive immune response is composed of highly specialized cells and processes that control or eliminate the invading pathogen.

1. What are CD4+ cells? What are CD8+ cells?
2. Explain why the immune system is able to generate a stronger, faster, and more effective response upon re-exposure to a pathogen.
3. T-lymphoblastic lymphoma is a neoplasm of immature T-cell precursors called lymphoblasts and often starts in the thymus. Predict anatomical and physiological changes that would occur to the surrounding organs in the mediastinum as a result of growth in a thymic mass.

Answer 1

A) CD4+ cells and CD8 + cells are type of lymphocytes which, help coordinate the immune response

CD8+ T cells often called cytotoxic T lymphocytes, or CTLs are very important for immune defence against intracellular pathogens, including viruses and bacteria, and for tumour surveillance, When a CD8+ T cell recognises its antigen and becomes activated, it secretes cytokines which have anti-tumour and anti-viral microbial effects. Sometimes these  CD8+ T cells can become overactive and cause immune related diorders.

CD4+ cells help coordinate the immune response by stimulating other immune cells, such as macrophages, B lymphocytes (B cells), and CD8 T lymphocytes (CD8 cells), to fight infection.If you have HIV, your CD4 cell count may be low. Without HIV treatment, your number of CD4 cells will likely keep falling. A lack of CD4 cells usually leads to more frequent infection.

B) Adaptive immunity also involves a memory to provide the host with long-term protection from reinfection with the same type of pathogen; on re-exposure, this memory will facilitate an efficient and quick response. The immune system adapts its response during an infection to improve the recognition of the pathogen, this improved response is than retained after the pathogen has been eliminated in the form of immuniological memory and allows the adaptive immunity system to mount faster and stronger attack each time this pathogen is encountered.;

C) The thymus gland is located in the anterior portion of the mediastinum.The mediastinum contains the heart, aorta, esophagus, thymus, trachea, lymph nodes and nerves. The tumor in the thymic area can spread to the heart, pericardium (the lining around the heart), and great vessels (the aorta and vena cava). Tumors located in the posterior (back) mediastinum can cause compression of the spinal cord. Tumors could occur in the esophagus also, enlargement of the lymph nodes can also occure, in addition to this it cause development of cyst or growth in the bronchial areas of lungs.