Interleukin-12: a bridge between innate resistance and adaptive immunity with a role in infection and acquired immunodeficiency

J Clin Immunol. 1994 May;14(3):149-61. doi: 10.1007/BF01533364.


Interleukin-12 (IL-12) is a disulfide-linked heterodimeric cytokine originally identified as a product of EBV-transformed B cell lines. Monocyte/macrophages are the physiologically most relevant producers of IL-12, in response to both Gram-positive and -negative bacteria, bacterial products, and intracellular parasites. Although IL-12 has an enhancing effect on the survival and growth of early hematopoietic progenitor cells, most of the IL-12 biological activity has been described on T and NK cells, on which it induces production of lymphokines, primarily IFN-gamma, enhances cytotoxic activity, and, in cooperation with other stimuli, increases proliferation. IL-12 is an inducer of development of T helper type 1 (Th-1) cells and the equilibrium between IL-12 and IL-4 is probably important for the balance in vivo between Th-1 and Th-2 responses. IL-12 has an important role in the host resistance to infection, in particular to intracellular pathogens, by activating macrophages through induction of IFN-gamma from NK and T cells and by enhancing cell-mediated immune responses, dependent on Th-1 cell development. Peripheral blood mononuclear cells from HIV-seropositive individuals are impaired in their ability to produce IL-12 in response to bacterial stimulation, and IL-12 restores in vitro some of the depressed immunological functions, suggesting that a defect in IL-12 production may have a pathogenic role in the immunodeficiency of HIV-infected individuals. Natural IL-12 appears to provide a regulatory link between innate resistance and the development of the antigen-specific adaptive immune response and the recombinant protein has therapeutic potential because of its activity against tumors and infections and its effectiveness as an adjuvant enhancing cell-mediated immunity in vaccination.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Acquired Immunodeficiency Syndrome / immunology*
  • Animals
  • Bacterial Infections / immunology*
  • Growth Substances
  • Humans
  • Immunity, Cellular
  • Interleukin-12 / immunology*
  • Protozoan Infections / immunology*
  • Receptors, Interleukin / immunology
  • Receptors, Interleukin-12
  • T-Lymphocytes, Helper-Inducer / immunology


  • Growth Substances
  • Receptors, Interleukin
  • Receptors, Interleukin-12
  • Interleukin-12