Usually tags such as GST (Glutathione S-transferse) and MBP (maltos-binding protein) are immunogenic simply because they are large proteins that contain many epitopes. It is preferable to use antigen proteins without these type of tags, however they can be used. However, other small tags, such as FLAG-tag, Myc-tag, V5-tag and His-tag do not interfere with specific antibody production.