Which of the following is not correctly matched ?

Options

A. Primary lymphoid organ : Thymus
B. Mucosa associated antibody : lgM Vaccination : Artificial active immunity
C. Vaccination : Artificial active immunity
D. Reservoirs of erythrocytes : Spleen

Answer

To determine which of the following statements is not correctly matched, we will analyze each statement one by one.

### Step 1: Analyze the first statement
**Statement:** Primary lymphoid organ is thymus.

**Analysis:**
- The primary lymphoid organs are the bone marrow and thymus.
- The thymus is indeed a primary lymphoid organ responsible for the maturation of T lymphocytes.

**Conclusion:** This statement is correctly matched.

### Step 2: Analyze the second statement
**Statement:** Mucosa associated antibody IgM vaccination is artificial active immunity.

**Analysis:**
- Active immunity occurs when the body produces its own antibodies in response to an antigen.
- Passive immunity involves the transfer of ready-made antibodies from one individual to another.
- IgM vaccination implies that IgM antibodies are being supplied from outside, which means the body is not producing them. Thus, this does not qualify as active immunity.

**Conclusion:** This statement is not correctly matched.

### Step 3: Analyze the third statement
**Statement:** Vaccination is artificial active immunity.

**Analysis:**
- Vaccination involves introducing a weakened or inactive form of a pathogen to stimulate the immune system to produce antibodies.
- This process is indeed a form of artificial active immunity since the body actively generates its own antibodies in response to the vaccine.

**Conclusion:** This statement is correctly matched.

### Step 4: Analyze the fourth statement
**Statement:** Spleen is considered as a reservoir of erythrocytes.

**Analysis:**
- The spleen does act as a reservoir for erythrocytes (red blood cells) and helps in their sequestration and destruction after their lifespan of about 120 days.
- It is also known as the "graveyard" of RBCs.

**Conclusion:** This statement is correctly matched.

### Final Conclusion
Based on the analysis, the statement that is not correctly matched is the second one: "Mucosa associated antibody IgM vaccination is artificial active immunity."