Sensitivity to animal-derived immune serum may lead to a serious condition called:

A. Interferon is a type of protein produced by the body in response to infections, particularly viral infections. It is not related to allergens.
B. Macrophage is a type of white blood cell that engulfs and digests pathogens, dead cells, and other debris. It is not an allergen.
C. An allergen is a substance that triggers an allergic reaction. It is considered a type of antigen—a foreign substance that the immune system recognizes and reacts to, often causing symptoms like inflammation, swelling, or itching in allergic individuals.
D. Antibody is a protein produced by B cells that binds to specific antigens, but it is not an allergen.

A. GALT (Gut-Associated Lymphoid Tissue) refers to lymphoid tissue found in the gastrointestinal tract, not a part of the lymph node.
B. The hilum is the indented area of a lymph node where blood vessels, nerves, and efferent lymphatic vessels (which carry lymph out of the node) exit the node.
C. Buboes are swollen lymph nodes, often a sign of infection like bubonic plague, not the area where vessels exit the lymph node.
D. Filariae are parasitic worms that can cause lymphatic filariasis, but they are not related to the structure of a lymph node.