Effect of prolactin on carcinoembryonic antigen-specific cytotoxic T lymphocyte response induced by dendritic cells.
The cytokine hormone prolactin (PRL) has been shown previously to modulate native cellular responses and maturation of antigen-presenting cells. Here we have addressed its effect on the antigen-specific response of cytotoxic T lymphocytes (CTL). CTL were generated from HLA-A2 lymphocytes after three rounds of stimulation with autologous dendritic cells loaded with HLA-A2-restricted carcinoembrionic antigen (CEA) Cap-1 (YLSGANLNL) peptide. Selected cultures were expanded on cytokine-supplemented feeder-layers, enriched for CD8+ lymphocytes and analysed for PRL-receptor (PRL-R) expression and PRL responsiveness. Resting CD8+ lymphocytes were negative for PRL-R, whereas antigen-activated CD8+ lymphocytes derived from long-term cultures were highly positive. Results of a 51Cr release assay showed CTL killing of CEA-loaded, but not unloaded, T2 cell line and the CEA-positive gastric carcinoma cell line KATO, but not of the CEA-negative T leukaemia cell line Jurkat. Interferon (IFN)-gamma release, evaluated in an ELISPOT assay against CEA-loaded T2, was enhanced (P < 0.05) by concentrations of PRL (12-25 ng/ml) very close to the physiological levels (6-20 ng/ml), but was decreased (P < 0.05) by high concentrations (200 ng/ml). Pre-incubation of the stimulators with the anti-MHC class I MoAb W6.32 induced a 40-60% decrease of the PRL-boosted IFN-gamma release, thus proving the MHC restriction of the lymphocyte response. Cytotoxicity against CEA-loaded T2 and KATO cell lines was also increased by 12-25 ng (P < 0.05) and decreased (P < 0.05) by 200 ng PRL. Pre-incubation of CTL with an antibody specific for the PRL-R almost completely abrogated this effect.
Matera
L
L
Department of Internal Medicine, University of Turin, Turin, Italy. lina.mater@unito.it
Beltramo
E
E
Martinuzzi
E
E
Buttiglieri
S
S
D002272:Carcinoembryonic Antigen / Q000276:immunology*; D003602:Cytotoxicity, Immunologic / Q000187:drug effects; D003713:Dendritic Cells / Q000276:immunology*; D004306:Dose-Response Relationship, Immunologic; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis; D011388:Prolactin / Q000494:pharmacology*; D013602:T-Lymphocytes, Cytotoxic / Q000187:drug effects* / Q000276:immunology; D014407:Tumor Cells, Cultured
D002272:Carcinoembryonic Antigen; D018984:Epitopes, T-Lymphocyte; D007371:Interferon-gamma; D011388:Prolactin