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D G Tice

Publications and source records attributed to D G Tice.

24 records · Page 2Linked to original sources
PubMed1983

Separation of human T-lymphocyte colony-forming cells on Percoll gradients.

Formation of T-lymphocyte colonies in semi-solid agar by mitogen-stimulated peripheral blood mononuclear cells is a sensitive indicator of a proliferative response. The exact identity of the T-lymphocyte colony forming cell (T-CFC) is not known, nor is it known if more than one T-CFC exists. It is possible that different subsets of mononuclear cells, each responding to diverse mitogens, give rise to different T-CFC. In this study, we separated mononuclear cells into seven subsets based on their density utilizing Percoll at concentrations of 40% to 55%. Following separation, the cells from each fraction were stimulated by phytohemagglutinin (PHA), pokeweed mitogen (PWM), concanavalin A (Con A), or staphylococcal protein A (SPA), and cultured in a semi-solid agar system. Each fraction was fully characterized by immunologic and cytochemical cell markers. Monocytes were found in the light density fraction, whereas T-lymphocytes and large granular lymphocytes were predominantly seen in the heavier density fractions. B lymphocytes were concentrated in the middle density fractions. Cells from fraction 1 (the lightest density fraction) formed significantly more T-cell colonies when stimulated by PHA than did fractions 4, 5, 6, or 7. This effect was not observed when other mitogens were used. We conclude that mononuclear cells can be separated into enriched cell subpopulations by Percoll fractionation and that PHA-stimulated T-CFC may also be enriched by Percoll fractionation. In addition, the data suggest that different subsets of T-CFC may exist.

Adult↗
PubMed1983

T lymphocyte colonies stimulated by different mitogens require diverse culture conditions.

Normal human peripheral blood mononuclear cells form colonies of T lymphocytes in a semi-solid agar matrix when stimulated by a variety of mitogens. In this report, we attempt to determine the optimal conditions for the formation of T lymphocyte colonies by cells stimulated with phytohemagglutinin (PHA), pokeweed mitogen (PWM), Concanavalin A (Con A), or Staphylococcal protein A (SPA). We conclude that optimal conditions differ for each mitogen used. Cultures stimulated by PWM or Con A showed a significant requirement for feeder layers composed of human peripheral blood mononuclear cells. Two-mercaptoethanol significantly enhanced the number of T-cell colonies when PWM, Con A, or SPA, but not PHA, were added as mitogens. Fetal calf serum (FCS) was required for optimal conditions when Con A or SPA but not PWM or PHA were used to stimulate mononuclear cells. Cells stimulated by PHA or PWM produced more T-cell colonies in a 2-step assay than a 1-step assay, whereas the reverse was true with Con A or SPA. Optimal cell concentrations, mitogen doses, and culture kinetics also differed for each mitogen used in the T-cell colony assay.

Cell Division↗
PubMed1980

Blood colony and cluster-forming activity during various stages of chronic granulocytic leukemia.

The colony and cluster-forming capacity of peripheral blood cells obtained from 25 patients who had chronic granulocytic leukemia (CGL) was evaluated in a double-layer agar culture. Increased numbers of colonies (mean, 264) and clusters (mean, 908) were obtained from the blood cells of nine of ten patients when first examined. The blood cells from 19 patients whose diseases were in the control phase formed normal or nearly normal numbers of colonies and clusters. During the aggressive phase, elevated blood colonies and clusters were observed in the 12 patients studied. Two to four times as many clusters as colonies were observed during these phases of CGL. At the time of blastic crisis, at least eightfold more blood clusters than colonies were observed in the eight patients studied. These studies indicate that the evaluation of blood colony and cluster-forming cells may provide a useful characterization of various clinical phases of CGL in individual patients.

Cell Aggregation↗
PubMedDate not supplied

Characterization of tumor-infiltrating lymphocytes from murine mammary adenocarcinomas.

The aim of this investigation was to assess the in vitro functional and phenotypic characteristics of lymphocytes isolated from C3H mouse mammary adenocarcinomas. A protocol was developed for the expansion of TILs in long-term culture. The homing pattern of TILs prepared and grown in this manner was studied. Cells that had been in culture for up to 96 days accumulated at higher levels in mammary tumors than in corresponding normal mammary tissue 24 hr after adoptive transfer. The ability of cultured TILs to lyse YAC-1 cells was determined. Peak activity was demonstrated by lymphocytes that had been in culture for three days. By two weeks in culture the level of cytotoxicity returned to that of fresh TILs, and after 45 days it was negligible. T cells were the major constituents in all preparations. The relative frequency of CD8+ cells remained fairly constant over time in culture, but that of CD4+ cells declined. At all time points the CD4:CD8 ratio for TILs was less than 1. The percentage of ASGM1+ bright cells among fresh TILs was low. It increased dramatically within 3 days, remained high for about 7 weeks, and then declined rapidly to pre-culture levels. An unusual large cell characterized by the presence of an intensely PAS positive peripheral region was observed.

Adenocarcinoma↗