Biology · Human Health and Diseases · NEET
The main difference is specificity and memory. Innate immunity is non-specific (it acts the same way on any pathogen) and is present at the time of birth. Acquired immunity is pathogen-specific (it targets one particular pathogen) and is built up during your life. Only acquired immunity has memory, so it responds faster on a second exposure. NEET often asks you to spot which of these two properties belongs to which type.
Innate immunity is present at the time of birth. This is a very common trap. The word 'acquired' means gained during life, so acquired immunity is NOT present at birth. If a question says 'non-specific defence present at the time of birth', the correct type is innate immunity, not acquired. NEET 2022 used exactly this swap as the wrong statement.
Innate immunity is NON-specific. It gives the same general response (barriers, phagocytosis, interferons) to every foreign agent. Acquired immunity is SPECIFIC. It recognises one particular pathogen and makes a matching response against it. Remember: innate = broad and general, acquired = targeted and precise.
Only acquired immunity has memory. Memory is the key feature of acquired immunity. On the first exposure the body gives a weak primary response, and it stores memory cells. On the next exposure to the SAME pathogen it gives a fast, strong secondary (anamnestic) response. Innate immunity has no memory, so its response never gets stronger with repeat exposure.
B-lymphocytes and T-lymphocytes carry out ACQUIRED immunity. B-cells make antibodies (humoral response) and T-cells run the cell-mediated response. Do not confuse them with the natural killer (NK) cells, neutrophils and macrophages of the innate cellular barrier. NK cells and phagocytes = innate; B-cells and T-cells = acquired.
Yes. The cellular barrier of innate immunity includes neutrophils, monocytes, macrophages and natural killer cells that phagocytose (engulf) and destroy microbes. This is why innate immunity gives immediate protection even before acquired immunity develops. NEET 2019 (Odisha) tested this: innate immunity is present at birth because it has NK cells that can phagocytose and destroy microbes.
Select the incorrect statement with respect to acquired immunity:
Humans have an acquired immune system that produces antibodies to neutralise pathogens. Still, the innate immune system is present at the time of birth because it:
Try the real previous-year questions from this chapter — each with the answer and a full solution.
NCERT lists two types: innate immunity and acquired immunity. Innate is non-specific and present from birth; acquired is pathogen-specific and develops during life with memory.
Innate immunity acts first and gives an immediate, general response. Acquired immunity is slower on the first exposure but becomes very fast and strong on later exposures because of memory cells.
Acquired immunity is specific. It recognises and targets one particular pathogen. Innate immunity is the non-specific type.
No. Innate immunity has no memory, so its response does not improve on repeat exposure. Only acquired immunity has memory (primary and secondary responses).
NEET repeatedly tests the swap between the two: 'non-specific and present at birth' (innate) versus 'specific and with memory' (acquired). Knowing which property belongs to which type lets you spot the incorrect statement quickly (asked in NEET 2022 and 2019).
