Anti-SHFL antibodies are used in the immunodetection of the protein shiftless antiviral inhibitor of ribosomal frameshifting. In humans, the canonical protein has a reported length of 291 amino acid residues and a mass of 33.1 kDa. Its subcellular localization is in the nucleus and cytoplasm. Up to 4 different isoforms have been reported for this protein. It is notably widely expressed in many tissue types. A member of the SHFL protein family, shfl is reported to inhibit programmed -1 ribosomal frameshifting (-1PRF) of a variety of mRNAs from viruses, such as HIV1, and cellular genes, such as PEG10. Synonyms for this target antigen include IRAV, RyDEN, SFL, shiftless antiviral inhibitor of ribosomal frameshifting protein, Repressor of yield of Dengue virus, and C19orf66. SHFL gene orthologs have been reported in the mouse, rat, bovine, frog, zebrafish and chimpanzee species.