Correct Answer: (C) unresponsiveness to antigens

Anergy describes a key immune tolerance mechanism where lymphocytes become unresponsive to specific antigens, preventing harmful overreactions. This process ensures the immune system avoids attacking self-tissues while remaining functional against true threats.​

Option Analysis

• (A) Mitochondrial dysfunction: Incorrect, as this refers to impaired energy production in cells’ powerhouses, unrelated to immune signaling or antigen response.​

• (B) Allergy to environmental antigens: Incorrect; allergies involve hyperactive responses (hypersensitivity), the opposite of anergy’s suppression.​

• (C) Unresponsiveness to antigens: Correct; anergy induces a hyporesponsive state in T or B cells after antigen exposure without full co-stimulation, promoting peripheral tolerance.​

• (D) A state of no energy: Incorrect; despite the root “a-” (without) and “erg-” (energy/work), anergy specifically denotes immunological inaction, not literal energy absence.​

Anergy refers to unresponsiveness to antigens, a vital process in immunology where immune cells like T lymphocytes fail to activate despite antigen exposure. This mechanism maintains tolerance, avoiding self-attack while allowing pathogen defense.​

Mechanisms of Anergy

Anergy induction occurs when T cells receive antigen signal 1 (via TCR) without co-stimulatory signal 2 from APCs, leading to hyporesponsiveness via altered signaling (e.g., calcium pathways, IL-2 blockade). It complements clonal deletion and regulatory T cells for immune homeostasis.​

Clinical Relevance

Therapeutically, inducing anergy curbs transplant rejection or autoimmunity (e.g., rheumatoid arthritis) without broad immunosuppression; reversing it aids anti-tumor immunity.​

MCQ Insights

In exams, anergy refers to unresponsiveness to antigens distinguishes it from mitochondrial issues or allergies, testing tolerance knowledge.​