Arabinofuranosyl-terminated and mannosylated lipoarabinomannans from Mycobacterium tuberculosis induce different levels of interleukin-12 expression in murine macrophages.

Lipoarabinomannan (LAM) is a major surface lipoglycan of Mycobacterium tuberculosis. In the present study, we demonstrated that arabinofuranosyl-terminated LAM (AraLAM) derived from a rapidly growing Mycobacterium sp., but not extensively mannosylated LAM derived from the Erdman strain, is capable of inducing interleukin-12 (IL-12) expression in murine macrophages. Since IL-12 is known to drive the differentiation of naive T cells toward T-helper type 1 (Th1) cell development, AraLAM may be an effective adjuvant in vaccines and immunotherapies that need Th1 responses.