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D T Harris

Publications and source records attributed to D T Harris.

At least 73 records · Page 4Linked to original sources
PubMed1987

Molecular mechanisms involved in T cell activation. II. The phosphatidylinositol signal-transducing mechanism mediates antigen-induced lymphokine production but not interleukin 2-induced proliferation in cloned cytotoxic T lymphocytes.

The phospholipid metabolism of cloned murine cytotoxic T lymphocytes (CTL) was examined under conditions in which the induction of proliferation by interleukin 2 (IL 2) and the stimulated production of lymphokine (macrophage-activating factor (MAF] by concanavalin A (Con A) and specific antigen occurred independently of each other. Activation of the CTL by either of the latter two stimuli resulted in changes in the metabolism of phosphatidylinositol (PI) that were early (less than 2.5 min), specific, and prolonged (6 to 8 hr). These changes were primarily characterized by an increase in phosphatidic acid (PA) and PI, with a decrease in phosphatidylinositol-4,5-bisphosphate. The duration of these phospholipid responses, particularly PA and PI, approximated the minimum time of CTL-stimulus interaction required to produce maximal titers of MAF. No changes were observed in other major classes of phospholipids during 8 hr of continuous stimulation. Stimulation with an irrelevant antigen had no effect on CTL phospholipid metabolism. In contrast to specific antigen or Con A, the T cell growth factor IL 2 failed to elicit specific and early biosynthetic responses from PA and PI. Instead, there were nonspecific biosynthetic responses from all major phospholipid classes (including phosphatidylcholine and phosphatidylethanolamine, as well as PA and PI) which occurred between 1 and 6 hr after IL 2 stimulation. Both 1,2-diacylglycerol (DAG) and inositol phosphates (IP), the hydrolytic products of PI turnover, were produced in response to MAF-inducing stimuli, but neither were detected in response to the proliferative stimulus IL 2. Together, these results indicate that the hydrolysis of PI and the concomitant production of the putative second messengers DAG and IP are involved in signaling the production of lymphokines (MAF) by CTL. On the other hand, the failure of IL 2 to elicit a full-spectrum PI response suggests that signals mediating CTL proliferation may utilize an alternate and still undefined pathway.

Animals↗
PubMed1987

Heterogeneity of human natural killer (NK) cells: enrichment of NK by negative-selection with the lectin from Erythrina cristagalli.

A novel technique for the isolation and enrichment of human natural killer (NK) cells from peripheral blood mononuclear cells (MNC) is described. Negative selection of MNC with the lectin from Erythrina cristagalli (ECA), whether by panning or agglutination in solution, resulted in a population of lymphocytes (5-20% of original MNC) highly enriched in cells exhibiting NK function. This enrichment was evident by a significant increase (range of 3-50-fold) in cells with large granular lymphocyte (LGL) morphology, K562 tumor-binding cells, cytotoxic activity, and cells expressing NK phenotypic markers (Leu 11+, OKM1+). Analysis of the cytolytic specificity of the cells demonstrated that the lytic spectrum was typical of endogenous NK. The effector cells were responsive to augmentation of cytotoxic potential by lymphokines (IL-2, IFN alpha, and IFN gamma) and capable of antibody-dependent cell-mediated cytotoxicity (ADCC). ECA-negative [ECA(-)] cells were equivalent to NK isolated by Percoll gradient fractionation. NK heterogeneity was demonstrated by the observation of a small percentage (1-5% of MNC) of NK in the ECA(+) population. This technique was found to be advantageous for the study of NK heterogeneity and NK biology.

Adolescent↗
PubMed1985

Proliferative quiescence of normal mast cells resembles that of cold-sensitive mutant mastocytoma cells. Dominant expression of the quiescent state in heterokaryons.

Normal murine peritoneal mast cells were fused to serum-deprived, non-proliferating cells of a cultured subline (41-SB-4) of the P-815 murine mastocytoma. Upon reincubation in medium containing 10% horse serum for 48 h, mono- and binuclear 41-SB-4 cells reentered S phase of the cell cycle, while mast cell X 41-SB-4 heterokaryons as well as mono- and binuclear mast cells remained in proliferative quiescence, indicating dominant expression of the quiescent state of mast cells. The quiescent state of normal mast cells thus resembles that of cold-sensitive (cs) mutant cells (21-F) of the undifferentiated P-815 mastocytoma: at the non-permissive temperature of 33 degrees C, the 21-F cells were found to enter a state of quiescence which is characterized by its dominant expression in heterokaryons and by morphological differentiation with the formation of metachromatically staining granules similar to those of mast cells. This suggests that the cellular control mechanisms involved in entry into proliferative quiescence and in morphological differentiation of cs 21-F cells may be analogous to those of normal mast cells and/or their precursors.

Animals↗
PubMed1985

Comparative activity and toxicity of cis-diamminedichloroplatinum (DDP) and a combination of doxorubicin, cyclophosphamide, and DDP in disseminated transitional cell carcinomas of the urinary tract.

From October 1978 to October 1981, 135 patients with disseminated transitional cell carcinomas of the urinary tract, with either measurable or evaluable disease, were randomized to receive either cis-diamminedichloroplatinum (DDP) or cyclophosphamide (CTX), Adriamycin (ADR) (Adria Laboratories, Columbus, Ohio), and DDP (CAD). DDP was given at a dose of 60 mg/m2, CTX at 400 mg/m2, and ADR at 40 mg/m2 intravenously every three weeks. Patients over the age of 65 and those with prior radiation received 75% of the dose initially. The dose was escalated if only mild toxicity developed. Of the patients on the CAD arm, 34% developed grade 3 or 4 hematologic toxicity, as compared to 3% in patients on the DDP therapy. Of the 93 patients with measurable disease, 48 received DDP. Seventeen percent had a partial or complete remission, as compared to 33% of the 45 patients on the CAD arm (P = .09). The crude median survival of patients on DDP was 6.0 months as compared to 7.3 months in patients receiving CAD (P = .17). We conclude that the CAD combination is more toxic than DDP with, at best, very marginal benefit in survival.

Actuarial Analysis↗
PubMed1985

Effects of tumor status on the regulation of natural killer cell activity by tumor-associated fetal antigens.

In the present study we examined the effects of a tumor-associated fetal antigen (TAFA-II) on the activity of natural killer (NK) cells isolated from human cancer patients. TAFA-II suppressed the NK cell response of some patients, and the level of suppression appeared to be independent of tumor type or stage of cancer therapy. No significant correlations were found between lymphocyte, neutrophil, monocyte, or eosinophil populations and TAFA-induced suppression of NK cell activity. TAFA-II effects were also not attributable to Ia+ cells or to OKT3, OKT4, or OKT8 positive cells. This work confirmed results obtained in the rat model, in which suppression appeared to be directly mediated on the NK cell.

Adult↗
PubMed1984

Direct transfer of antigen-specific cytolytic activity to noncytolytic cells upon fusion with liposomes derived from cytolytic T cell clones.

Murine cytolytic T lymphocytes (CTL) clones were solubilized in Nonidet P-40 detergent, and the matrix and membrane proteins separated from the nuclear constituents. These proteins, in combination with exogenous lipids and Sendai virus envelope proteins, were used to construct liposomes that were then fused with noncytolytic cloned T cell recipients. The resultant fusion products were found to be highly cytolytic and appeared to express the same specificity as the original donor clone. Further analysis showed that the liposomal transfer process was extremely efficient. Moreover, in addition to noncytolytic T cell clones, three transformed T cell lines and one B cell line were found to express specific cytolytic activity after fusion with appropriate liposomes. Inhibition experiments using monoclonal antibodies against target cell antigens, as well as analysis of the lytic reactivity pattern of the fusion products, confirmed the high degree of specificity conferred to the recipient cells. This study thus indicates that the two characteristics typically associated with CTL, namely antigen-specific recognition and cytolytic activity, can be solubilized from CTL and transferred to recipient cells that do not express these characteristics.

Animals↗
PubMed1984

Antigen recognition by H-2-restricted cytolytic T lymphocytes is not mediated by two independent receptors.

Detergent-solubilized murine cytolytic T lymphocytes (CTL) clones were incorporated into Sendai virus-containing synthetic liposomes. When these liposomes were then fused with other CTL clones possessing a different non-cross-reacting specificity, the fusion products were observed to lyse target cells recognized by both parental CTL clones. This method was then used with two H-2-restricted CTL clones of different, non-cross-reacting specificities (anti-H-2b-H-Y or anti-H-2b Moloney leukemia virus). Once again, the fusion products were found to be lytic against both target cells recognized by the parental clones, but in no instance was there any observable lysis of target cells bearing the same nominal antigen in the context of different H-2 molecules. These results provide strong evidence that antigen recognition by H-2-restricted CTL is not mediated by two independent antigen receptors.

Animals↗
PubMed1984

Target cell susceptibility to immune lysis and expression of MHC antigens are independent of position in the cell cycle.

We have investigated the effects of progression through the mitotic cell cycle upon the tumor (P815) cell line's expression of H-2 antigens and susceptibility to immune cytolysis. By using a combination of DNA quantitation by Hoechst 33342 staining and fluorescence-activated cell sorter analysis we were able to obtain pure populations of G1, S, and G2+M cells for study. Furthermore, by employing a fluorescence quenching technique utilizing bromodeoxyuridine substitution we were able to monitor the times required for the P815 cells to transit each of the various phases. By using mAb and cloned CTL populations with well-defined specificities we observed that neither H-2 antigen expression nor lytic susceptibility to mAb plus complement or CTL fluctuated with cell cycle progression. Each of the three major MHC loci (H-2Kd, -Dd, and -Ld) was analyzed. These results demonstrated that expression of H-2 antigens and susceptibility to immune lysis were independent of a cell's position in the cell cycle.

Animals↗
PubMed1983

Functional aspects of T-cells from patients with non-Hodgkin's lymphoma. Responses to self, TNP-modified self, and alloantigens.

Peripheral blood T-cell proliferative responses to autologous non-T cells, Trinitrophenyl-modified autologous non-T cells, and allogeneic lymphocytes were measured in 27 patients with non-Hodgkin's lymphoma (NHL) and 22 age- and sex-matched healthy controls. The NHL patients were not receiving chemotherapy or immunosuppressive drugs at the time of the study and had not received such agents for at least 3 weeks prior to the study. Responses to autologous non-T cells (the autologous mixed lymphocyte reaction [AMLR] ) and to TNP-modified non-T cells were significantly lower in NHL patients than in controls (P less than 0.00002 and P less than 0.0001, respectively), but responses to alloantigens were not significantly different between the NHL patients and the controls (P greater than 0.85). There was no definite correlation of low AMLR responses with disease activity, and normal AMLR responses did not define a subgroup of patients relative to histopathologic findings. The deficiency of AMLR in NHL patients appears to be due to a disturbance in the T-cell compartment.

Humans↗
PubMed1983

Hormonal therapy and chemotherapy of renal-cell carcinoma.

At best, hormonal treatment gives a small proportion of objective responses in patients treated; most commonly the responses are incomplete and of short duration. In practice, treatment with a progestational agent, such as medroxyprogesterone acetate, is often used because of minimal production of unwanted side effects and lack of more effective therapy. Single-agent chemotherapy appears to add little in terms of tumor response, although a small fraction of patients will have favorable responses to single agents such as vinblastine. Combination chemotherapy may give a slightly higher response rate according to results reported in several small series, but there is a considerable increase in toxicity, and, as yet, no clearly definable improvement in patient survival. Further studies are needed to explore the roles of new agents, new drug combinations, and perhaps interactions of modalities such as chemotherapy, hormonal therapy, and immunotherapy. Methods of in vitro testing or testing in the nude mouse or a similar model could provide ways to obtain information in this regard more quickly and without undue exposure of the patient to ineffective and potentially toxic therapy.

Adenocarcinoma↗
PubMed1982

Spontaneous genetic hypertension in the rat and its relationship to reduced ac cochlear potentials: implications for preservation of human hearing.

We present controlled laboratory studies of the spontaneously hypertensive rat which indicate that hypertension is an important pathophysiological risk factor in age-related hearing loss. Our results are in concert with previous retrospective clinical studies that pointed to this possibility in man. Hypertension as a risk factor for hearing loss is within the bounds of known measures of diagnosis, treatment, and even prevention, with monitoring early in life. Because hypertension is such a major public health problem in the United States, in view of our results it is possible that its treatment and early diagnosis will benefit a significant number of people who would otherwise lose their hearing with advancing age. We compared the round window ac cochlear potential-sensitivity and -intensity functions in 10 female spontaneously hypertensive rats and 10 female normotensive Wistar-Kyoto control rats. The animals were all 12 months old and weighed between 170 and 250 g. The normotensives had higher maximum cochlear potential-intensity values compared with the hypertensives: 1,000 Hz (P less than 0.005), 5,000 Hz (P less than 0.005), and 10,000 Hz (P less than 0.01). One-microvolt isopotential cochlear potentials for the low frequencies of the normotensives showed greater sensitivity than those of the hypertensives: 100 Hz (P less than 0.05), 200 Hz (P less than 0.10), 290 Hz (P less than 0.05), and 2,000 Hz (P less than 0.10). Blood pressure of the hypertensive group was significantly greater than that of the normotensive rats (P less than 0.001). The hearts and aortas of the hypertensive group were hypertrophied. Autonomic imbalance, platelet aggregation, decreased arterioles, and natriuretic hormone were discussed as possible etiologies for the measured sensory hearing loss.

Acoustic Stimulation↗
PubMed1981

Elicitation of anti-vesicular stomatitis virus cytotoxic T lymphocytes by using purified viral and cellular antigens incorporated into phospholipid vesicles.

We evaluated the minimal molecular and cellular requirements for elicitation of anti-vesicular stomatitis virus (VSV) cytotoxic T lymphocytes (CTL). The results indicated that lipid vesicles containing the purified major surface glyco-protein of VSV (G protein) and purified H-2K(k) glycoproteins elicited specific H-2K(k)-restricted anti-VSV CTL. These antiviral CTL were shown to be Ly 1(-),2(+). However, both Ly 1(+),2(-) and Ly1(-),2(+) T-cell subpopulations were shown to be required for elicitation of these CTL.

Animals↗
PubMed1981

Lysis of target cells infected with vesicular stomatitis virus (VSV) in the presence of tunicamycin by anti-VSV cytotoxic T lymphocytes.

We have analyzed the requirement for the expression of the major surface glycoprotein (G protein) of vesicular stomatitis virus (VSV) on target cells for recognition and lysis by anti-VSV cytotoxic T lymphocytes (CTL). In addition, we have attempted to determine if the carbohydrate moieties on the G protein are required for recognition and lysis by anti-VSV CTL. When VSV (Orsay) is grown at 30 degrees C in the presence of tunicamycin (TM), glycosylation of G protein is inhibited; however, nonglycosylated G protein is found on the surface of the cell and active virus particles are produced. In contrast, VSV (Orsay) grown at 39 degrees C in the presence of TM produces low titers of virus and the presence of G protein on the surface of cells is not detectable. The susceptibility of these target cells to lysis by anti-VSV CTL was analyzed. The results suggest that expression of the G protein is required for target cell lysis by anti-VSV CTL. However, the presence of the carbohydrate moieties on the G protein are nt an absolute requirement for recognition by anti-VSV CTL. VSV-infected target cells incubated in the presence of TM were lysed by anti-VSV CTL up to 50 to 80% of the infected target cell control. This result suggests either that some clones of anti-VSV CTL recognize carbohydrate moieties or that carbohydrate moieties play some as yet undefined nonantigenic role in the recognition of the target antigen by the CTL receptor.

Animals↗
PubMed1981

Elicitation of anti-H-2 cytotoxic T lymphocytes with antigen-modified H-2 negative stimulator cells.

By a newly developed technique, we have modified H-2k-negative cells in such a way as to render them capable of elicitation of anti-H-2 CTL. Purified H-2Kk and/or partially purified Iak glycoproteins were incorporated into lipid vesicles that contained the hemagglutinin-neuraminidase (HN) glycoprotein and the fusion (F) glycoprotein of Sendai virus. These lipid vesicles were incubated with H-2-negative tumor cells (R1-) in a manner that resulted in rendering these cells capable of eliciting anti-H-2Kk CTL. The presence of Iak on the surface of the modified stimulator cell had a significant effect on the proportion of anti-H-2Kk CTL possessing a particular Lyt phenotype. Primary effector cells elicited by an H-2Kk-Iak difference were primarily Lyt 1-, 2+, whereas primary anti-H-2Kk CTL elicited by an H-2Kk difference alone were predominantly Lyt 1+, 2+.

Animals↗
PubMed1980

Antigen-liposome modification of target cells as a method to alter their susceptibility to lysis by cytotoxic T lymphocytes.

A method of liposome modification of cell surfaces to render unsuitable target cells susceptible to lysis by anti-viral cytotoxic T lymphocytes (CTLs) is described. Liposomes containing the hemagglutinin-neuraminidase (HN) and fusion (F) glycoproteins of Sendai virus as well as purified H-2Kk cells and rendering those cells susceptible to lysis by B10. A anti-Sendai virus or anti-H-2Kk CTLs. The absence from the modifying liposomes of the HN or F proteins or H-2Kk antigens eliminated the ability of the target cells to be recognized and lysed by either effector cell population. Vesicles containing HN, H-2Kk molecules, and inactive fusion protein (Fo) were not capable of increasing the susceptibility of h-2-negative target cells to lysis. Liposomes containing inactive fusion protein were similarly unable to render H-2-positive target cells susceptible to lysis by anti-Sendai virus CTLs, suggesting that fusion of the liposomes to the cell surface is a prerequisite to lysis. It did not appear that attachement of liposomes to the cell surface was sufficient for generation of susceptible targets, however, because attachment to the cell surface was observed, as long as the HN glycoprotein was present in the liposomes. These results indicate that purified H-2Kk glycoproteins are target antigens for anti-H-2k CTLs and that B10 . A anti-Sendai virus CTLs recognize in an H-2-restricted manner the HN, F, or both glycoproteins of Sendai virus in the context of the purified H-2Kk glycoproteins. This technique of liposome modification of cell surfaces has potential applications in the examination of CTL antigen recognition and immunotherapy of many viral and neoplastic diseases.

Animals↗