Humoral immunity and cell-mediated immunity are the two parts of acquired immunity. In humoral (antibody-mediated) immunity, B-lymphocytes make antibodies that float in the blood and fight pathogens. In cell-mediated immunity (CMI), T-lymphocytes themselves act against the target. Memory hook: "Humoral = Humour/fluid = antibodies in blood (B-cells); Cell-mediated = the T-cell does the job."
Acquired immunity has two arms. Humoral immunity uses B-cell antibodies floating in blood to fight free pathogens; cell-mediated immunity uses T-cells that attack directly and cause graft rejection.
Your doubts, answered
What is the difference between humoral and cell-mediated immunity?
Both are parts of acquired immunity. Humoral immunity uses antibodies (proteins) made by B-lymphocytes that circulate in the blood and body fluids to fight free pathogens. Cell-mediated immunity (CMI) uses T-lymphocytes that act directly, without secreting antibodies. So the simple split is: humoral = B-cells + antibodies in fluid; cell-mediated = T-cells doing the action.
Why is it called 'humoral' immunity?
NCERT says the antibodies are found in the blood, so the response is called the humoral immune response. The old word 'humor' meant body fluid. Because antibodies work while dissolved in blood and body fluids, this defence got the name humoral. This is a common NEET memory point: humoral = fluid/blood = antibodies.
Which cells are involved in humoral immunity and which in cell-mediated immunity?
Humoral immunity is carried out by B-lymphocytes, which produce antibodies. Cell-mediated immunity (CMI) is carried out by T-lymphocytes. Note one NCERT trap: T-cells do NOT secrete antibodies themselves, but they HELP B-cells to produce antibodies. So T-cells assist humoral immunity but they mediate CMI directly.
Why is graft (organ transplant) rejection cell-mediated and not humoral?
When an organ is transplanted, the body sees the graft tissue as 'nonself'. NCERT states the cell-mediated immune response is responsible for graft rejection, because T-lymphocytes directly attack the foreign transplanted cells. Antibodies (humoral) act mainly against free-floating antigens in blood, not against solid transplanted tissue. This exact idea has been asked in NEET 2017 and NEET 2019.
Do T-cells make antibodies?
No. This is a frequent confusion. NCERT clearly says T-cells themselves do not secrete antibodies; only B-lymphocytes produce antibodies. T-cells only help B-cells make antibodies. So if a NEET option says 'T-cells secrete antibodies', it is wrong.
⚠️ The NEET trap ✗ Graft rejection is caused by the humoral (antibody-mediated) immune response. ✓ Graft rejection is caused by the cell-mediated immune response (T-lymphocytes) because the body attacks the 'nonself' transplanted tissue directly. 🧠 NEET 2017 and 2019 both asked this. Remember: solid graft tissue = T-cells attack = cell-mediated, NOT humoral. Antibodies fight free antigens in fluid, not transplanted organs.
Real NEET questions
2019
Which of the following immune responses is responsible for rejection of kidney graft?
A · Auto-immune response
B · Humoral immune response
C · Inflammatory immune response
D · Cell-mediated immune response ✓
Solution: Graft/transplant rejection happens because the body tells 'self' from 'nonself', and the cell-mediated immune response (T-lymphocytes) rejects the graft. This is why tissue and blood-group matching plus lifelong immunosuppressants are needed. Humoral (antibody-mediated) immunity acts on free antigens, not on transplanted tissue, so it is wrong here. (NCERT Ch7, p.136)
2017
Transplantation of tissues/organs fails often due to non-acceptance by the patient's body. Which type of immune-response is responsible for such rejections?
A · Autoimmune response
B · Cell-mediated immune response ✓
C · Hormonal immune response
D · Physiological immune response
Solution: NCERT states the cell-mediated immune response (mediated by T-lymphocytes) is responsible for graft rejection because the body differentiates 'self' from 'nonself'. Autoimmune response is attack on one's OWN cells, not a graft. There is no 'hormonal' immune response, and physiological barriers belong to innate immunity. (NCERT Ch7, p.136)
2025
Which of the following type of immunity is present at the time of birth and is a non-specific type of defence in the human body?
A · Cell-mediated Immunity
B · Humoral Immunity
C · Acquired Immunity
D · Innate Immunity ✓
Solution: Innate immunity is the non-specific defence present at birth (physical, physiological, cellular and cytokine barriers). Humoral and cell-mediated immunity are the two SPECIFIC parts of ACQUIRED immunity, so they develop after exposure and are not present at birth. This PYQ tests whether you can separate humoral/cell-mediated (acquired, specific) from innate. (NCERT Ch7, p.134)
Solved Human Health and Diseases NEET PYQs
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Are humoral and cell-mediated immunity part of innate or acquired immunity?
Both are parts of acquired immunity. Acquired immunity is pathogen-specific and has memory. Innate immunity is different: it is non-specific and present at birth.
What is the H2L2 antibody used in humoral immunity?
Each antibody has four peptide chains: two light (L) and two heavy (H) chains, so it is written H2L2. B-lymphocytes make these antibodies in humoral immunity. Types include IgA, IgM, IgE and IgG.
Do T-cells help humoral immunity at all?
Yes. Although T-cells mediate cell-mediated immunity, NCERT says T-cells also help B-cells to produce antibodies. So T-cells assist humoral immunity but do not secrete antibodies themselves.
Which immunity fights viruses inside cells and cancer cells?
Cell-mediated immunity (T-lymphocytes) mainly deals with infected cells, transplanted 'nonself' cells and abnormal cells, while humoral immunity (antibodies) acts on free pathogens and toxins in blood and fluids.
Is graft rejection ever a NEET repeat question?
Yes. NEET asked graft/transplant rejection as cell-mediated in both 2017 and 2019. Always mark cell-mediated (T-lymphocytes) for graft rejection, never humoral.
