Molecular Actions of Prolactin in the Immune System

Abstract

Several lines of research have pointed to a role for PRL and IRF-1 in modulating the immune response. The molecular analyses of PRL-R, its ligand PRL, and a PRL-inducible transcription factor, IRF-1, provide insights and generate tools with which to reexamine PRL's role in modulating immune function cell biology in both normal lymphocytes as well as in clinical diseases involving hyperprolactinemia. In the next few years, detailed analysis of the functional domains of the Stat and JAK proteins, cytokine receptors, and other signaling proteins will undoubtedly elucidate how these molecules regulate distinct patterns of gene transcription in various lymphoid cell types. As knock-out animals of PRL, PRL-R, JAKs, and Stats develop and become available for analysis along with IRF-1 knock-out mice, a better understanding of which immune targets and responses are affected or regulated by PRL will emerge. These transgenic animal studies, combined with comprehensive ongoing molecular, genetic, biochemical, and immunological studies in tissue culture, will help to elucidate the immunoregulatory properties of PRL and define its role as a cytokine.