Abstract
The human tetraspan molecule CD81 is a coreceptor in B and T cell activation and a candidate receptor for hepatitis C virus infection. We examined the surface expression of CD81 on B and T lymphocytes by quantitative flow cytometry. Upon cellular activation, CD81 surface levels were rapidly reduced. This reduction occurred as early as 1 h after activation and was linked to the release of CD81-positive microparticles into the cell culture medium. CD81 mRNA levels were not affected early after activation, but the release of CD81-positive microparticles was rapidly enhanced. In addition, intercellular transfer of CD81 was observed upon coculture of CD81-positive donor cells (Jurkat T cell line) with CD81-negative acceptor cells (U937 promonocytic cell line). This transfer was rapidly increased upon T cell activation, coinciding with enhanced CD81 release from activated Jurkat cells. We propose that the release and intercellular trafficking of CD81-positive microparticles regulate the expression of CD81 surface receptors in lymphocytes and play a role in the immune response during infections.
Publication types
-
Research Support, Non-U.S. Gov't
MeSH terms
-
Antigens, CD / genetics
-
Antigens, CD / isolation & purification
-
Antigens, CD / metabolism*
-
B-Lymphocyte Subsets / immunology
-
B-Lymphocyte Subsets / metabolism
-
Cell Communication / genetics
-
Cell Communication / immunology*
-
Cell Membrane / genetics
-
Cell Membrane / immunology
-
Cell Membrane / metabolism
-
Cell-Free System / immunology
-
Cell-Free System / metabolism
-
Cells, Cultured
-
Centrifugation, Density Gradient
-
Coculture Techniques
-
Down-Regulation / immunology
-
Endosomes / genetics
-
Endosomes / immunology
-
Endosomes / metabolism
-
Endosomes / ultrastructure
-
Exocytosis / genetics
-
Exocytosis / immunology
-
Extracellular Space / immunology*
-
Extracellular Space / metabolism*
-
Humans
-
Jurkat Cells / immunology
-
Jurkat Cells / metabolism
-
Jurkat Cells / ultrastructure
-
Lymphocyte Activation / immunology
-
Membrane Proteins / genetics
-
Membrane Proteins / isolation & purification
-
Membrane Proteins / metabolism*
-
Protein Transport / immunology
-
RNA, Messenger / antagonists & inhibitors
-
RNA, Messenger / metabolism
-
T-Lymphocyte Subsets / immunology
-
T-Lymphocyte Subsets / metabolism
-
T-Lymphocyte Subsets / ultrastructure
-
Tetraspanin 28
-
U937 Cells
Substances
-
Antigens, CD
-
CD81 protein, human
-
Membrane Proteins
-
RNA, Messenger
-
Tetraspanin 28