Which of these is used as vector in gene therapy for SCID?

Options

A. Arbovirus
B. Retrovirus
C. Enterovirus
D. Parvovirus

Answer

**Step-by-Step Solution:**

1. **Understanding SCID**: Severe Combined Immunodeficiency (SCID) is a genetic disorder characterized by the disturbed development of functional T cells and B cells caused by numerous genetic mutations. Gene therapy is a potential treatment for SCID.

2. **Identifying Vectors**: In gene therapy, vectors are used to deliver genetic material into cells. Common vectors include viruses, which can effectively introduce new genes into host cells.

3. **Evaluating Options**:
- **Option 1: Arbovirus**: This type of virus is transmitted by arthropods and is not suitable for gene therapy for SCID. Thus, this option is incorrect.
- **Option 2: Retrovirus**: Retroviruses are RNA viruses that can integrate their genetic material into the host's DNA. This property makes them useful for gene therapy, particularly for SCID, as they can effectively deliver the therapeutic gene into the host's cells. This option is correct.
- **Option 3: Enterovirus**: Enteroviruses are associated with various diseases but are not used as vectors in gene therapy for SCID. Therefore, this option is incorrect.
- **Option 4: Parvovirus**: Parvoviruses primarily affect animals and are not used in gene therapy for SCID. Thus, this option is also incorrect.

4. **Conclusion**: After evaluating all options, the correct vector used in gene therapy for SCID is the **retrovirus**.

**Final Answer**: The vector used in gene therapy for SCID is the **retrovirus**.

---