The fluid formed when tissue fluid passes from the intercellular spaces into the lymphatic vessels is:

A. Chyle is a type of lymphatic fluid rich in fats absorbed from the intestines, but it is not the primary basis of all lymphatic fluid.
B. Secretions of lymph nodes contribute immune cells and filtering functions but do not form the main component of lymph.
C. Plasma is the correct answer. Lymphatic fluid originates from interstitial fluid, which in turn is derived from plasma that leaks out of capillaries. This fluid enters the lymphatic system and becomes lymph.
D. MALT (Mucosa-associated lymphoid tissue) is involved in immune responses in mucosal membranes but does not form the basis of lymphatic fluid.

A. Serum sickness is the correct answer. It is a type III hypersensitivity reaction that can occur when the body reacts to proteins in animal-derived immune serum, often used in treatments like antitoxins or antivenoms. Symptoms may include rash, fever, joint pain, and swelling.
B. Rejection syndrome typically refers to the immune system's rejection of transplanted organs or tissues, not a response to serum.
C. Kaposi sarcoma is a cancer associated with human herpesvirus 8 (HHV-8), most commonly seen in immunocompromised individuals, such as those with AIDS. It is unrelated to immune serum reactions.
D. Hay fever (allergic rhinitis) is an allergic reaction to airborne substances like pollen, not to animal-derived serum