T lymphocytes from normal human peritoneum are phenotypically different from their counterparts in peripheral blood and CD3- lymphocyte subsets contain mRNA for the recombination activating gene RAG-1.
The surface antigens of peritoneal lymphocytes of healthy human individuals were studied. B lineage cells comprised 2.3% of the total peritoneal lymphocyte population. Although the majority of peritoneal cavity lymphocyte (PCL) T cells expressed alpha beta T cell receptor (TcR), up to 17% expressed gamma delta TcR. The majority of PCL exhibited markers of the thymus-dependent lineage (CD2+ CD3+ TcR alpha beta + CD4+ or CD8 alpha + beta +) and surface antigens associated with memory and activation (CD45RO+ CD11a+ CD18+ CD49d+ HLA-DR). Up to 92% of both CD4+ and CD8+ T cells bore CDw60, thus characterizing the T cell subset containing helper activity for mitogen-driven B cell differentiation. The majority of PCL T cells were CD8+ and, in addition, up to 60% of this population expressed the homodimeric CD8 alpha + beta -. Messenger RNA for the recombination activating gene RAG-1 was examined in CD3- PCL depleted of CD19+ lineage cells. The PCL population which comprised cells containing RAG-1 mRNA transcripts was CD19-, surface IgM-, cytoplasmic IgM- and CD2- CD3- CD4- CD8- CD56-. However, this population was CD7+ (approx. 75%), and contained both CD7- CD34+ (up to 3%) and CD7- CD34+ (up to 3%) cells. These findings are compatible with the hypothesis that the adult human peritoneum provides a microenvironment capable of supporting a thymus-indenpendent differentiation of T lymphocytes.
Hartman
J
J
Department of Medicine, University of Munich, Germany.
Maassen
V
V
Rieber
P
P
Fricke
H
H
D000328:Adult; D001483:Base Sequence; D017252:CD3 Complex / Q000276:immunology / Q000378:metabolism; D005260:Female; D018398:Homeodomain Proteins; D006801:Humans; D016130:Immunophenotyping; D008969:Molecular Sequence Data; D010537:Peritoneum / Q000276:immunology*; D011506:Proteins / Q000276:immunology* / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D016176:T-Lymphocyte Subsets; D013601:T-Lymphocytes / Q000276:immunology*
D017252:CD3 Complex; D018398:Homeodomain Proteins; D011506:Proteins; D012333:RNA, Messenger; C064658:RAG-1 protein