A novel group of phospholipase A2s preferentially expressed in type 2 helper T cells.
We report a novel phospholipase A(2) (PLA(2)), group XII (GXII) PLA(2), distinct from other cysteine-rich groups with a catalytic histidine motif, by its 20-kDa size and distribution of the 14 cysteine residues within the protein. Alternative spliced forms with distinct subcellular localization, designated GXII-1 and GXII-2, were identified by reverse transcription-polymerase chain reaction. Importantly, GXII PLA(2)s, in particular GXII-2 PLA(2), and group V PLA(2), but not group X PLA(2), were selectively expressed in murine type 2 helper T (Th2) clones and in vitro differentiated mouse CD4 Th2 cells as compared with type 1 helper T clones and cells. Stimulation with anti-CD3 appreciably up-regulated expression of GXII PLA(2)s and group V PLA(2) by steady state analysis of the Th2 cells as compared with type 1 helper T cells. These results suggest that group XII and group V PLA(2)s might participate in helper T cell immune response through release of immediate second signals and generation of downstream eicosanoids.
Department of Immunology and Infectious Diseases, Harvard School of Public Health, Division of Rheumatology, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA. iho@hsph.harvard.edu
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Bingham
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Glimcher
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D003001:Cloning, Molecular; D008969:Molecular Sequence Data; D010741:Phospholipases A / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D016415:Sequence Alignment; D017421:Sequence Analysis; D018418:Th2 Cells / Q000201:enzymology* / Q000276:immunology
D010741:Phospholipases A