Jeg-3 human choriocarcinoma-induced immunosuppression: downregulation of interleukin-2, interleukin-2 receptor alpha-chain, and its Jak/Stat signaling pathway.
OBJECTIVE
The mechanisms of the immunosuppressive and immunosuppression-inducing capacities of Jeg-3 human choriocarcinoma cell line supernatants (HCSs) are not yet completely understood. The influence on interleukin (IL)-2, IL-4 and interferon (IFN)-gamma production; IL-2 receptor (IL-2R) alpha-, beta-, and gamma-chain; and the signaling pathway molecules Janus kinase (Jak)1, Jak3, signal transducers and activators of transcription (Stat)1, Stat3, and Stat5 should be investigated.


METHODS
For assessment of IL production, whole peripheral venous blood from healthy donors was stimulated with phorbol-myristate-acetate and ionomycine. Secretion of ILs was blocked with monensine. Intracellular ILs were analyzed by flow cytometry. For IL-2R and signaling pathway molecule analysis, peripheral blood lymphocytes were stimulated with phytohemagglutinin (PHA). IL-2R chains were measured by flow cytometry, and Jaks/Stats by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot.


RESULTS
Phorbol-myristate-acetate and ionomycine strongly increase the percent-age of IL-2+ cells; an additional 50% HCSs significantly suppresses the percentage to, or below the level of unstimulated cells. IFN-gamma production is strongly decreased by HCSs in some cases, but not in others. PHA stimulates IL-2R alpha-, beta-, and gamma-chain expression and their signaling pathway molecules Jak1, Jak3, Stat1, Stat3, and Stat5. 50% HCS downregulates the alpha-chain and slightly upregulates the beta-chain. Jak1, Jak3, Stat1, Stat3, and Stat5 expression is suppressed approximately to, or below the level of unstimulated cells.


CONCLUSIONS
HCS forcefully blocks the production of IL-2; the IL-2R alpha-chain; and Jak1, Jak3, Stat1, Stat3, and Stat5 expression. The observed phenomena might be caused by downregulation of an IL-2R regulation gene, and might play a key role in the expansion of choriocarcinoma, and possibly in the survival of the fetal allograft.
Kilic
M
M
Institut für Klinische Immunologie, Friedrich-Schiller-Universität, Jena, Germany.
Flossmann
E
E
Flossmann
O
O
Vogelsang
H
H
Junker
U
U
Chaouat
G
G
Markert
U R
UR
D000328:Adult; D015153:Blotting, Western; D002822:Choriocarcinoma / Q000276:immunology*; D004268:DNA-Binding Proteins / Q000378:metabolism; D015536:Down-Regulation / Q000502:physiology; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007108:Immune Tolerance; D007376:Interleukin-2 / Q000096:biosynthesis*; D008214:Lymphocytes / Q000276:immunology; D008297:Male; D010920:Placenta / Q000276:immunology; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D015375:Receptors, Interleukin-2 / Q000378:metabolism*; D015398:Signal Transduction; D015534:Trans-Activators / Q000378:metabolism; D014407:Tumor Cells, Cultured
D004268:DNA-Binding Proteins; D007376:Interleukin-2; D015375:Receptors, Interleukin-2; D015534:Trans-Activators; D011505:Protein-Tyrosine Kinases