A widely used drug that suppresses cellular immunity, inhibits prostaglandin and leukotriene synthesis and increases the catabolism of IgG antibody is:
**Core Concept**
The question is testing the student's knowledge of a drug that modulates the immune response, inhibits inflammation, and affects antibody catabolism. This involves understanding the pharmacological properties of corticosteroids, specifically their effects on cellular immunity, prostaglandin and leukotriene synthesis, and immunoglobulin metabolism.
**Why the Correct Answer is Right**
The correct answer is a corticosteroid, which suppresses cellular immunity by inhibiting the activation and proliferation of T-lymphocytes. Corticosteroids also inhibit the synthesis of prostaglandins and leukotrienes, which are pro-inflammatory mediators involved in the inflammatory response. Additionally, corticosteroids increase the catabolism of IgG antibodies, leading to a decrease in antibody levels and a reduction in the immune response. This is achieved through the induction of the enzyme acid glycoprotein (AAG), which binds to IgG and increases its clearance from the circulation.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is likely a non-steroidal anti-inflammatory drug (NSAID), which primarily inhibits prostaglandin synthesis but does not suppress cellular immunity or increase antibody catabolism.
**Option B:** This option is likely an immunosuppressant, which may inhibit cellular immunity but does not specifically inhibit prostaglandin and leukotriene synthesis or increase antibody catabolism.
**Option C:** This option is likely an antihistamine, which does not affect cellular immunity, prostaglandin and leukotriene synthesis, or antibody catabolism.
**Clinical Pearl / High-Yield Fact**
Corticosteroids are widely used in various clinical settings, including asthma, rheumatoid arthritis, and transplant rejection. However, long-term use can lead to adrenal insufficiency, osteoporosis, and increased susceptibility to infections.
**Correct Answer:** C. Corticosteroids, such as prednisone or dexamethasone, are widely used drugs that suppress cellular immunity, inhibit prostaglandin and leukotriene synthesis, and increase the catabolism of IgG antibodies.