True or False: Vaccinations can cause the diseases they are designed to prevent.

Explanation: B cells are a type of lymphocyte that plays a crucial role in the immune response by recognizing and binding to specific antigens. When a B cell encounters an antigen that matches its specific receptor, it becomes activated and differentiates into plasma cells, which produce antibodies against the antigen.

Incorrect choices:

b. Cytotoxic T cells are responsible for directly attacking and killing infected or abnormal cells during cell-mediated immunity. They do not primarily recognize antigens during the immune response.

c. Macrophages are antigen-presenting cells that engulf and process pathogens to present their antigens to other immune cells, such as T cells and B cells. While they are involved in antigen recognition, they are not the primary cells responsible for this function.

d. Red blood cells do not have a direct role in antigen recognition or the immune response. Their primary function is to transport oxygen throughout the body.

Explanation: Sjögren's syndrome is an autoimmune disorder in which the immune system attacks and damages the salivary and lacrimal glands, resulting in dry eyes and dry mouth.

Incorrect choices:

a. Rheumatoid arthritis primarily affects the joints, causing inflammation and joint damage.

c. Crohn's disease is an autoimmune disorder that affects the gastrointestinal tract, leading to inflammation and ulcers.

d. Psoriasis is a chronic skin condition characterized by red, scaly patches on the skin, and it is not related to the salivary and lacrimal glands.