Selective Modulation of the Major Histocompatibility Complex Class II Antigen Presentation Pathway following B Cell Receptor Ligation and Protein Kinase C Activation

doi:10.1074/jbc.272.6.3641

Selective Modulation of the Major Histocompatibility Complex Class II Antigen Presentation Pathway following B Cell Receptor Ligation and Protein Kinase C Activation*

From the Centre d'Immunologie INSERM-CNRS de Marseille-Luminy, 13, 288 Marseille, France

^§ To whom correspondence should be addressed:
CIML, Parc Scientifique de Luminy, Case 906, 13 288 Marseille, France
. Tel.: (33) 4 91 26 94 36; Fax: (33) 4 91 26 94 30; E-mail: davoust{at}ciml.univ-mrs.fr

Abstract

We noticed that B cell receptor ligation or phorbol 12-myristate 13-acetate treatment induced intracellular vesicles containing major histocompatibility complex (MHC) class II and invariant chain (Ii), and increased the amount of transmembrane p12 Ii fragments coimmunoprecipitated with class II molecules. To determine the influence of protein kinase C activation on the MHC class II presentation pathway, we analyzed the subcellular distribution of Ii, the induction of SDS-stable forms of class II molecules, and their ability to present different antigens. Ii chains visualized with luminal and cytoplasmic directed antibodies appeared in early endosomal compartments accessible to transferrin in response to phorbol 12-myristate 13-acetate treatment, whereas transmembrane Ii degradation products equivalent to the p12 Ii fragments were colocalized with the B cell receptors internalized after cross-linking. Protein kinase C activation delayed in parallel the formation of SDS-stable forms of class II molecules and reduced the presentation of antigenic determinants requiring newly synthesized class II αβ-Ii complexes. These data indicate that B cell activation affects Ii processing and MHC class II peptide loading in endosomal compartments intersecting the biosynthetic pathway.

Footnotes

↵^‡ Recipient of a Predoctoral Fellowship from the Ministère de l'Enseignement Supérieur et de la Recherche.
↵* This work was supported by institutional grants from INSERM, CNRS, and by grants from the Association pour la Recherche sur le Cancer (ARC) and the Ligue Nationale de lutte contre le Cancer. The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵¹ The abbreviations used are:

MHC

major histocompatibility complex

FITC

fluorescein isothiocyanate

PBS

phosphate-buffered saline

Ab

antibody

mAb

monoclonal antibody

Ii

invariant chain

CLIP

class II-associated invariant chain peptide;

αCyt.I Ab

anti-I-Aβ cytoplasmic domain Ab

αCyt.Ii

anti-Ii cytoplasmic domain Ab

αLum.Ii

anti-Ii luminal domain Ab

αCLIP

anti-Ii CLIP peptide Ab

APC

antigen-presenting cell

BCR

B cell receptor

PMA

phorbol 12-myristate 13-acetate

PAGE

polyacrylamide gel electrophoresis

PKC

protein kinase C

SLIP

small leupeptin-induced invariant chain protein

HEL

hen egg lysozyme.
↵² N. Barois, F. Forquet, and J. Davoust, unpublished results.
- Received August 27, 1996.