title: Lead influences translational or posttranslational regulation of Ia expression and increases invariant chain expression in mouse B cells.
abstract: The molecular mechanisms governing the increased cell surface expression of major histocompatibility complex (MHC) class II molecules (Ia) on lead-treated mouse B cells was investigated. Lead has been shown to directly cause a selective, two-fold increase in the B cell's surface density of both products of the I region of the mouse MHC, I-A and I-E. In the present study, Western blot analysis showed that Pb increases the total cellular pool of I-A beta-chain by twofold. The increase in cellular I-A was not found to be due to increased messenger RNA (mRNA) for either the alpha- or the beta-chain of I-A. Biosynthetic labeling studies showed that Pb increases the translation or the stability of the Ia-associated invariant chain (Ii or gamma) and possibly the beta-chain of Ia. Collectively these results suggest that Pb increases the B cell's surface Ia by influencing translational or posttranslational regulation of Ia and/or Ia-associated chains.
authors.affiliation: Department of Microbiology and Immunology, Albany Medical College, New York 12208.
authors.forename: M J
authors.initials: MJ
authors.lastname: McCabe
authors.forename: J A
authors.initials: JA
authors.lastname: Dias
authors.forename: D A
authors.initials: DA
authors.lastname: Lawrence
mesh_terms: D000818:Animals; D000944:Antigens, Differentiation, B-Lymphocyte; D001402:B-Lymphocytes / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D005260:Female; D000949:Histocompatibility Antigens Class II / Q000235:genetics / Q000378:metabolism*; D066298:In Vitro Techniques; D015847:Interleukin-4 / Q000494:pharmacology; D007854:Lead / Q000633:toxicity*; D051379:Mice; D008808:Mice, Inbred CBA; D011499:Protein Processing, Post-Translational / Q000187:drug effects
chemical_list: D000944:Antigens, Differentiation, B-Lymphocyte; D000949:Histocompatibility Antigens Class II; C045084:invariant chain; D015847:Interleukin-4; D007854:Lead