title: A protein in pig spleen similar to immune suppressive protein of stress.
abstract: OBJECTIVE
  To purify a protein in pig spleens, which was similar to immune suppressive protein of stress (ISPS), and characterize its properties and functions.
  
  
  METHODS
  1) Pig spleen was extracted in dilute hydrochloric acid. 2) The extract was ultra-filtrated for having high molecular weight proteins (Mr>30 000). 3) The filtrates were purified with FPLC affinity chromatography. 4) The elute from FPLC was used for T-lymphocyte proliferation and ELISA test. 5) Lastly, SDS-PAGE was used to determine the molecular weight and purity of the final product.
  
  
  RESULTS
  A protein purified from pig spleen (the pig ISPS homologue) inhibited concanavalin A (Con A)-induced mouse lymphocyte proliferation. The molecular weight of this protein was about Mr 190 000. It has a stronger selectivity against T-lymphocyte line such as Jurkat cell line and mastocyte line (P8l5) and has a weaker inhibitory activity on macrophage line (U937).
  
  
  CONCLUSIONS
  A protein similar to rat/mouse ISPS was found in pig spleen. This may provide an opportunity to study its roles in tumors and autoimmune diseases.
authors.affiliation: Department of Physiology and Pathophysiology, Health Science Center, Peking University, Beijing 100083, China.
authors.forename: Hong-Yan
authors.initials: HY
authors.lastname: Fu
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
authors.forename: Gui-Feng
authors.initials: GF
authors.lastname: Ding
authors.forename: Shao-Guang
authors.initials: SG
authors.lastname: Fan
mesh_terms: D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D006801:Humans; D019169:Jurkat Cells / Q000187:drug effects; D008214:Lymphocytes / Q000166:cytology / Q000187:drug effects; D051379:Mice; D008807:Mice, Inbred BALB C; D008970:Molecular Weight; D013154:Spleen / Q000737:chemistry*; D013312:Stress, Physiological / Q000378:metabolism*; D013491:Suppressor Factors, Immunologic / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D013552:Swine
chemical_list: D013491:Suppressor Factors, Immunologic