Holzinger et al. (1995) isolated a full-length cDNA clone for LST1, the human equivalent of the mouse B144 sequence. LST1 encodes interferon-gamma (IFNG)-inducible 800-nucleotide transcripts that are present in lymphoid tissues, T-cells, macrophages, and histiocyte cell lines. The cDNA contains 3 long open reading frames (ORFs), with the most likely ORF encoding a transmembrane protein. The authors suggested that LST1 may have a role in immune response.

Rollinger-Holzinger et al. (2000) identified 7 novel LST1 splice variants in peripheral blood mononuclear cells, bringing to 14 the total number of LST1 variants identified in various cell types. These variants, designated LST1A through LST1N, encode both transmembrane and soluble proteins.