The immunoglobulin disulfides do not join:

Options

A. Two heavy chains
B. Light chain with heavy chain
C. Two light chains
D. All of the above

Answer

To solve the question regarding which components of immunoglobulins do not join via disulfide bonds, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Immunoglobulin Structure**:
- Immunoglobulins (Ig) are composed of heavy chains and light chains. Each immunoglobulin molecule has two heavy chains and two light chains.

2. **Identify Regions of Immunoglobulin**:
- The immunoglobulin structure has variable regions (where antigen binding occurs) and constant regions. The variable regions are crucial for recognizing antigens.

3. **Recognize the Role of Disulfide Bonds**:
- Disulfide bonds are covalent bonds that help stabilize the structure of immunoglobulins. They connect heavy chains to light chains and also connect the two heavy chains together.

4. **Analyze the Options**:
- **Option 1**: Two heavy chains - These are connected by disulfide bonds.
- **Option 2**: Light chain with heavy chain - These are also connected by disulfide bonds.
- **Option 3**: Two light chains - These are not connected by disulfide bonds as they do not interact in the same way as heavy chains do.

5. **Conclusion**:
- The correct answer is that disulfide bonds do not join the two light chains.

### Final Answer:
The immunoglobulin disulfides do not join **the two light chains**.