Modulatory Effect Mediated By PRL/PRLr Pathway On Human Immune Cells

Objective: In order to confirm the influence of the PRL/PRLr pathway on human immune regulation, we investigated the expression of prolactin receptor (PRLr) in human immune system, and the relationship between prolactin (PRL) and the synergic stimulating signal correlated to the activation of the immune cell.Methods: Specimens of human immune system were obtained from both central and peripheral immune organs, including thymus(thymoma), bone marrow, lymph node and peripheral blood mononuclear cells from patients with SLE. Specific fragments of PRLr mRNA were obtained through RNA isolation and RT-PCR amplification. Human T cell leukemia cell line named JurkatDl.l cell line, which was proved to express PRLr mRNA by RT-PCR, was selected to be used as a model for the definition of the individual role of PRL. We used Phytohemagglutinin (PHA), recombinant human prolactin (rhPRL) and combination of them to stimulate the JurkatDl.l cells, Negative control groups were also established. After having been cultivated for 24 hours, the cells werecollected and were immunofluorescence stained with FITC-conjugated mouse anti-human CD 154 monoclonal antibody IgGl. Flow cytometry was used to estimate the expression of CD 154 on the cells. Results:1. PRLr mRNA was detected from the thymoma, bone marrow, lymph node, peripheral blood mononuclear cells and the JurkatDl.l cell line. All the PRLr cDNA fragments generated by PCR were as long as the expected length, which was 276bp.2. Stimulated by the combination of PHA and rhPRL, the expression of the CD 154 on Jurkat cells significantly increased (53.89?.321%, p<0.05). As for the PHA and rhPRL groups respectively, there was no difference compared with that of the control groups (20.5 8 ?.475%, 20.89?.793% vs 24.23 ?.057% p>0.05).Conclusions:1. Our study confirmed that prolactin recepror mRNA was expressed in human central immune organs such as thymus and bone marrow and peripheral immune organs such as lymph node and peripheral blood mononuclear cells. This phenomenon provided a biologic structural evidence that neuro-endocrine hormone PRL might play a modulating role on immune cells from receptor's point of view.2. PRL exerts its role by binding to PRLr on the cell membrane, and then the PRL-PRLr complex internalization subsequently induces someintracellular phenomenon. So as done in human immune system. Our experiment found that PRL increased the expression of the synergic stimulating signal CD 154. The present study provided a new insights into relationship between PRL and the second signal system in immune response.