       Document 0536
 DOCN  M9620536
 TI    Processing of exogenous heat-aggregated (denatured) and particulate
       (native) hepatitis B surface antigen for class I-restricted epitope
       presentation.
 DT    9602
 AU    Schirmbeck R; Bohm W; Melber K; Reimann J; Institute for Medical
       Microbiology, University of Ulm, Germany.
 SO    J Immunol. 1995 Nov 15;155(10):4676-84. Unique Identifier : AIDSLINE
       MED/96062283
 AB    Many cell types efficiently present an epitope of the hepatitis B
       surface Ag (HBsAg) to murine class I-restricted CTL following an in
       vitro pulse with native 22-nm HBsAg particles. Processing of exogenous
       HBsAg particles required its cytochalasin B-insensitive uptake and acid
       proteolysis in an endocytic compartment, was insensitive to brefeldin A
       and cycloheximide, and did not involve regurgitation of antigenic
       peptides. In contrast, after an in vitro pulse of cells with exogenous,
       heat-denatured 1-micron HBsAg aggregates, only macrophages (but not
       other cell types tested) presented the Ld-restricted HBsAg epitope
       efficiently to CTL. Processing of exogenous HBsAg aggregates required
       its cytochalasin B-sensitive uptake, was insensitive to brefeldin A, and
       involved regurgitation of antigenic peptides. Processing of the two
       different, exogenous HBsAg preparations for class I-restricted epitope
       presentation thus involved alternative pathways: an endocytic pathway
       for native 22-nm particles, and a phagocytic pathway for denatured
       1-microns aggregates. Both HBsAg preparations displayed different
       immunogenicity for class I-restricted CTL in vivo when delivered without
       adjuvants: native HBsAg particles were of high immunogenicity, and
       denatured HBsAg aggregates were of low immunogenicity. Class
       I-restricted CTL are thus primed in vivo after endocytic processing of
       native HBsAg particles as well as phagocytic processing of denatured
       HBsAg aggregates.
 DE    Animal  *Antigen Presentation  Cells, Cultured  CD8-Positive
       T-Lymphocytes/*IMMUNOLOGY  Endocytosis/IMMUNOLOGY  Heat  Hepatitis B
       Antigens/CHEMISTRY/*IMMUNOLOGY  Histocompatibility Antigens Class
       I/*IMMUNOLOGY  Mice  Mice, Inbred BALB C  Phagocytosis/IMMUNOLOGY
       Recombinant Proteins/CHEMISTRY/IMMUNOLOGY  Support, Non-U.S. Gov't
       JOURNAL ARTICLE

       SOURCE: National Library of Medicine.  NOTICE: This material may be
       protected by Copyright Law (Title 17, U.S.Code).

