Annotations are based on the standardized rules of the IMGT Scientific chart. They take into account each step of the Immunoglobulin and T cell Receptor chain synthesis. IMGT annotations allow a standardized description of the nucleotide and protein sequences, of the 2D and 3D structural data, and of the polymorphic data, whatever the antigen receptor (Immunoglobulin (IG) or T cell Receptor (TR)), whatever the chain type, and whatever the species (IMGT Repertoire).
In IMGT/LIGM-DB there are two levels of annotation, initially the keyword information is checked and LIGM standardized keywords are assigned, this represents level K. Standardized keywords are assigned in the order of the keyword tree structure. Subsequent annotation involves the assignment of feature keys to the entries. Then, the annotation level becomes F. The annotation level of each entry is indicated on the first (ID) line of the entry.
- "Keyword level": sequences to which are associated IMGT/LIGM-DB standardized keywords
- "Fully annotated": sequences annotated with IMGT/LIGM-DB labels, in addition to the IMGT/LIGM-DB standardized keywords.
Click here for an example of an annotated
IMGT/LIGM-DB flatfile of human IG.
Click here for an example of an annotated IMGT/LIGM-DB flatfile of mouse TR.
A tool IMGT/Automat has been developed for the automatic annotation of IG and TR cDNA sequences .
IMGT annotation rules provide information on practical questions raised in the process of annotation.
 Giudicelli V., Protat C., and Lefranc M.-P. The IMGT strategy for automatic annotation of IG and TR cDNA sequences: IMGT/Automat European Conference on Computational Biology, ECCB' 2003, Paris, France 27-30 september 2003.