Which antibodies activate the B–lymphocyte for further release of antibodies ?

Options

A. IgG
B. IgA
C. IgE
D. IgD

Answer

To determine which antibodies activate B-lymphocytes for the further release of antibodies, we can analyze the functions of the different types of immunoglobulins (antibodies) mentioned in the question.

### Step-by-Step Solution:

1. **Understanding B-Lymphocytes**: B-lymphocytes, or B cells, are a type of white blood cell that plays a crucial role in the immune response. When activated, they can differentiate into plasma cells that produce antibodies.

2. **Role of Antibodies**: Antibodies are proteins produced by B cells that help identify and neutralize pathogens such as bacteria and viruses. Different classes of antibodies have different roles in the immune response.

3. **Types of Antibodies**: The question provides four options: IgG, IgA, IgE, and IgD. We need to evaluate the role of each of these antibodies in activating B-lymphocytes.

4. **IgD**: This antibody is primarily found on the surface of B cells and is involved in the initiation of B cell activation. However, it does not play a direct role in activating B cells for antibody release.

5. **IgE**: This antibody is associated with allergic responses and defense against parasitic infections. It does not activate B cells for the production of antibodies.

6. **IgG**: This is the most abundant antibody in the bloodstream and plays a significant role in the immune response. While it can signal B cells, it is not primarily responsible for their activation.

7. **IgA**: This antibody is mainly found in mucosal areas, such as the gut, respiratory tract, and urogenital tract, as well as in saliva, tears, and breast milk. IgA is known for its role in mucosal immunity and is involved in the activation of B cells, leading to the production of antibodies.

8. **Conclusion**: Based on the functions of the antibodies discussed, the correct answer to the question is **IgA**. IgA is responsible for activating B-lymphocytes for further antibody release.

### Final Answer:
The antibodies that activate the B-lymphocyte for further release of antibodies is **IgA**.