Question
Characteristics of innate immunity include
- First line of defense
- Active role of T lymphocytes
- Memory cells are present
- Compliment system is involved a) 1, 3 are correct b) 1, 2 are correct c) 1, 4 are correct d) 2, 4 are correct Question numbers (xi) – (xv) are single response types
Answer
Key characteristics of innate immunity: present from birth, providing an immediate response (minutes to hours) without requiring prior exposure; non-specific (recognizes broad, conserved microbial patterns via pattern recognition receptors, e.g., Toll-like receptors, rather than specific antigens); no immunological memory generated (response magnitude does not improve with repeated exposure, unlike adaptive immunity); mediated by physical/chemical barriers (skin, mucosa, gastric acid), phagocytic cells (neutrophils, macrophages), natural killer cells, and the complement system. Without the original four numbered statements from the source question, the specific combination intended by the examiner cannot be confirmed.