The surface phenotype of activated T lymphocytes

Abstract

Summary The surface phenotype of T cells reflects both their relative maturity and their activation slate. To determine the pattern of surface markers characteristic of activated T cells, purified mature T cells were stimulated in vitro for periods of 0-5-5 days with Concanavalin-A (Con-A) or phorbol myristic acetate (PMA) and ionomycin, fluorescein-labelled with monoclonal antibodies, then analysed by flow cytometry. The level of expression of the function-associated antigens CD4 (L3T4) and CD8 (Ly-2) decreased transiently early after activation with PMA/ionomycin, but not after stimulation with Con-A. Both stimuli caused a small drop in the level of CD3 and the T cell antigen receptor (TCR). At no time was CD3, CD4 or CD8 completely lost from the surface. Following activation Pgp-1, the interleukin-2 (IL-2) receptor (as detected by the monoclonal antibody 7D4) and the peanut agglutinin (PNA) receptor were gained by a proportion of cells, MEL-14 was lost by a proportion of cells, and no change was observed in the expression of heat stable antigen. Thy-1 or Ly-1. From the present data no evidence has been found for the generation of the 'immature', CD4~ CD8" phenotype found in the thymus by activation of mature T cells. During T cell development, however, changes in expression of Pgp-1, MEL-14, the IL-2 receptor and the PNA receptor may be associated with activation, rather than diiferentiation per se.

Selective Effects of mTOR Inhibitor Sirolimus on Naïve and CMV-Specific T Cells Extending Its Applicable Range Beyond Immunosuppression

“…Upregulation of classical activation (CD25, CD69) and exhaustion marker (PD-1, Lag-3) expression was markedly increased after sirolimus treatment in CMV-specific T cells (Figure 3B) compared to total CD8 + T cells (Figure S2B). These results were not unexpected since the transient expression of exhaustion markers is also used to describe T-cell activation (37, 38). Similar to the lack of effect on the expression of CTLA-4 and Tim-3 on multimer + T cells (Figure 3B), treatment had no significant effect on the overall expression of activation and exhaustion markers on total CD8 + T cells (Figure S2B).…”

Activation-Induced Inhibition of Interleukin 6–Mediated T Cell Survival and Signal Transducer and Activator of Transcription 1 Signaling

“…To address this possibility, we sorted naive and memory phenotype T cells from untreated, 6-mo-old BALB/c mice. The markers CD44, CD62L, and CD45RB have all been reported to be useful in discriminating memory from naive T cells (30)(31)(32). Memory T cells express higher levels of CD44 and lower levels of both CD62L and CD45RB compared with resting T cells.…”

Nucleosome assembly in mammalian cell extracts before and after DNA replication.

“…In recent years, subcellular systems which allow both ( Oxford University Press initiation and continuation of SV40 DNA replication in vitro using either SV40 origin-containing plasmids or SV40 minichromosomes as templates have been developed. They have greatly improved our understanding of the molecular processes involved in eukaryotic DNA replication (reviewed in DePamphilis, 1987;Kelly, 1988;Challberg and Kelly, 1989; Stillman, 1989); These systems rely on crude cytoplasmic extracts prepared either from transformed human cell lines, namely HeLa or 293 cells, supplemented with high amounts of purified SV40 large T-antigen (T-Ag) (Li and Kelly, 1984;Stillman and Gluzman, 1985;Wobbe et al, 1985) or crude cellular extracts prepared from SV40 infected monkey cells (CV-1), the natural host for SV40 (Li and Kelly, 1984;Yamaguchi and DePamphilis, 1986;Decker et al, 1987). All of the in vitro replication systems mimic most of the known properties of SV40 DNA replication in vivo except that under such experimental conditions, no chromatin is formed and replication products formed in the presence of cytosolic extract supplemented with T-Ag are mostly relaxed (form II) DNA molecules.…”