Document 0192
 DOCN  M9480192
 TI    Differential CD4-dependent regulation of naive and memory CD4+ T cell
       adhesion is not related to differences in expression and function of CD4
       and p56lck.
 DT    9410
 AU    Lecomte O; Hivroz C; Mazerolles F; Fischer A; INSERM U132, Hopital
       Necker-Enfants Malades, Paris, France.
 SO    Int Immunol. 1994 Apr;6(4):551-9. Unique Identifier : AIDSLINE
       MED/94289336
 AB    We have previously reported that antigen-independent adhesion of CD45RO+
       memory CD4+ T cells to B cells is negatively regulated by CD4-MHC class
       II interaction, whereas that of CD45RA+ naive CD4+ T cells is not. We
       have now found that both cross-linking of CD4 ligands [anti-CD4 mAbs,
       HIV gp160 (env) protein and a 12mer peptide encompassing the 35-46
       sequence of the HLA-DR beta 1 domain] on CD4+ naive T cells and
       activation-induced conversion of naive CD4+ T cells to memory T cells
       leads to CD4-dependent down-regulation of adhesion. To further elucidate
       CD4-dependent differential regulation of naive and memory T cell
       adhesion to B cells, we investigated the expression and function of CD4
       and p56lck, a tyrosine kinase associated with the cytoplasmic domain of
       CD4. p56lck tyrosine kinase activity was equally enhanced by anti-CD4
       mAbs and gp160 (120) in the two subsets. Furthermore, cell-surface CD4
       down-modulation by phorbol myristate acetate or anti-CD4 mAbs was
       similar in the two subsets, which express the same amounts of both
       cell-surface CD4 and CD4-associated p56lck. Finally, the pattern of
       tyrosine phosphorylation of cellular proteins induced by gp120 (160) was
       similar in the two subsets. Taken together, these results indicate that
       the different sensitivity of naive and memory CD4+ T cells to
       CD4-dependent regulation of adhesion is not accounted for by differences
       in the tyrosine kinase activity of p56lck; it probably, therefore,
       involves a step downstream of p56lck or another pathway differentially
       used in naive and memory CD4+ T cells.
 DE    Amino Acid Sequence  Antigens, CD4/BIOSYNTHESIS/*PHYSIOLOGY
       B-Lymphocytes/PHYSIOLOGY  Cell Adhesion/*IMMUNOLOGY  Cross-Linking
       Reagents  Human  Immunoblotting  Lymphocyte Transformation  Molecular
       Sequence Data  Precipitin Tests  Protein-Tyrosine
       Kinase/BIOSYNTHESIS/*PHYSIOLOGY  Support, Non-U.S. Gov't  T4
       Lymphocytes/*PHYSIOLOGY  JOURNAL ARTICLE

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