Table 5.

Characteristics of single-domain antibodies in comparison to conventional antibodies.

1.	Small molecular weight (12–15 kDa) (Their long, heavy-chain regions make them capable of targeting specific epitopes, such as the receptor-binding site of the S protein)
2.	High penetration in tissues due to small size.
3.	Ease of manipulation. (Can be used for new immunobiotechnological medication).
4.	High solubility and stability in harsh environments, such as high temperatures or denaturing conditions.
5.	Low Immunogenicity.
6.	Easily selected by Phage Display.
7.	Easy production in bacteria and yeast. (Because they lack the glycan-harboring Fc domain, making them easier to make than the standard monoclonal antibodies).
8.	High specificity. (Recognize native epitopes, which are rare for classical antibodies).
9.	Easy production and suitable cost.
10.	Low risk of antibody-dependent enhancement (ADE) of infection. (Due to the absence of the Fc region. However, it shortens the half-life of these molecules, a disadvantage that could be overcome by attaching them to polyethylene glycol or human albumin).