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M Roederer

Publications and source records attributed to M Roederer.

At least 37 records · Page 2Linked to original sources
PubMed1999

Characterization of circulating T cells specific for tumor-associated antigens in melanoma patients.

We identified circulating CD8+ T-cell populations specific for the tumor-associated antigens (TAAs) MART-1 (27-35) or tyrosinase (368-376) in six of eleven patients with metastatic melanoma using peptide/HLA-A*0201 tetramers. These TAA-specific populations were of two phenotypically distinct types: one, typical for memory/effector T cells; the other, a previously undescribed phenotype expressing both naive and effector cell markers. This latter type represented more than 2% of the total CD8+ T cells in one patient, permitting detailed phenotypic and functional analysis. Although these cells have many of the hallmarks of effector T cells, they were functionally unresponsive, unable to directly lyse melanoma target cells or produce cytokines in response to mitogens. In contrast, CD8+ T cells from the same patient were able to lyse EBV-pulsed target cells and showed robust allogeneic responses. Thus, the clonally expanded TAA-specific population seems to have been selectively rendered anergic in vivo. Peptide stimulation of the TAA-specific T-cell populations in other patients failed to induce substantial upregulation of CD69 expression, indicating that these cells may also have functional defects, leading to blunted activation responses. These data demonstrate that systemic TAA-specific T-cell responses can develop de novo in cancer patients, but that antigen-specific unresponsiveness may explain why such cells are unable to control tumor growth.

Antigens, Neoplasm↗
PubMed1999

Differential representations of memory T cell subsets are characteristic of polarized immunity in leprosy and atopic diseases.

We identified functionally polarized subsets of CD4 memory T cells on the basis of the expression of CD11a, CD45RA and CD62L. Within the several phenotypically distinct subsets of CD4 memory cells are two that, upon stimulation, produce primarily IL-4 (MT(2), CD45RA(-)CD62L(+)CD11a(dim)) or primarily IFN-gamma (MT(1), CD45RA(-)CD62L(-)CD11a(bright)). In addition, four other phenotypically distinct subsets of CD4 cells have unique cytokine profiles. To determine the clinical relevance of the representation of these cell types, we analyzed blood from patients with the chronic diseases leprosy and atopy. These diseases are characterized as immunologically polarized, since T cell responses in affected individuals are often strongly biased towards T(h)1 (dominated by IFN-gamma production) or T(h)2 (IL-4 production). We show here that this polarization reflects homeostatic or differentiation mechanisms affecting the representation of the functionally distinct subsets of memory CD4 T cells, MT(1) and MT(2). Significantly, the representation of the MT(1) and MT(2) subsets differs dramatically between subjects with tuberculoid leprosy (a T(h)1 disease), or lepromatous leprosy or atopic disease (T(h)2 diseases). However, there was no difference in the cytokine profiles of these or any of the other finely resolved CD4 subsets, when compared between individuals across all disease states. Thus, it is the representation of these subsets in peripheral blood that is diagnostic of the polarized state of the immune system.

CD4-Positive T-Lymphocytes↗
PubMed1997

8 color, 10-parameter flow cytometry to elucidate complex leukocyte heterogeneity.

We developed the chemistry, instrumentation, and software technologies needed to measure, simultaneously and independently, eight different fluorescent molecules on individual cells. Conjugation of these fluorochromes to monoclonal antibodies is straightforward; all immunofluorescence staining is accomplished with direct stains only. We built a hybrid flow cytometer with eight fluorescence detectors and two light scatter channels, with excitation provided by three spatially separated laser beams emitting at 407 nm, 488 nm, and 595 nm. The fluorescence compensation required to make the data orthogonal is of sufficient complexity that it cannot be performed manually; thus, we use software to compensate the data post hoc, based on data collected from singly stained compensation control samples. In this report, we evaluate the 8 color staining technology. Of the seven fluorochromes other than fluorescein, six have a useful brightness at least as great as fluorescein. Three of the fluorochromes (phycoerythrin, allophycocyanin, and the Cy5 resonance energy tandem of phycoerythrin) are considerably brighter than fluorescein and are useful for detecting antigens expressed at low levels. Finally, we show the power and utility of the 8 color, 10-parameter technology using staining experiments on both human and murine immune systems.

Animals↗
PubMed1997

Long-term depletion of naive T cells in patients treated for Hodgkin's disease.

We investigated the representation of T cells in patients who had been treated for Hodgkin's disease (HD). We found a marked depletion in both CD4 and CD8 naive T-cell counts that persists up to 30 years after completion of treatment. In contrast, CD4 and CD8 memory T-cell subsets recovered to normal or above normal levels by 5 years posttreatment. Thus, the previously-reported long-term deficit in total CD4 T-cell counts after treatment for HD is due to specific depletion of naive T cells. Similarly, total CD8 T-cell counts return to normal by 5 years only because CD8 memory T cells expand to higher than normal levels. These findings suggest that the treatment (mediastinal irradiation) results in a longterm dysregulation of T-cell subset homeostasis. The profound depletion of naive T cells may explain the altered T-cell function in treated patients, including the poor response to immunization after treatment for HD. Further, in some individuals, we identified expansions of unusual subsets expressing low levels of CD8. Eight-color fluorescence-activated cell sorting analyses showed that these cells largely express CD8alphaalpha homodimers and CD57, consistent with the phenotype of potentially extrathymically derived T cells. In addition, these cells, both CD4+ and CD4-, are probably cytotoxic lymphocytes, as they express high levels of intracellular perforin. In adults treated for HD, an increased activity of extrathymic T-cell differentiation may partially compensate for the loss of thymic-derived T cells.

Adolescent↗
PubMed1997

HIV does not replicate in naive CD4 T cells stimulated with CD3/CD28.

In this report, we demonstrate that the T cell tropic strain of HIV, LAI, does not replicate in naive CD4 T cells stimulated by cross-linking CD3 and CD28. In contrast, LAI replicates well in memory CD4 T cells stimulated in the same way. Unlike this physiologically relevant stimulation, PHA stimulates productive LAI replication in both naive and memory T cells. These studies were conducted with highly purified (FACS-isolated) subsets of CD4 T cells identified by expression of both CD45RA and CD62L. Remixing of purified T cells showed that naive T cells do not suppress LAI replication in memory T cells and that memory T cells do not restore LAI expression in naive T cells. The suppression of productive LAI replication in naive T cells is not due to differential expression of viral coreceptors, nor is it due to inhibition of activation of the important HIV transcription factors, nuclear factor-kappaB and activator protein-1. The inherent resistance of naive T cells to productive HIV infection, coupled with their proliferative advantage as demonstrated here, provides a sound basis for proposed clinical therapies using ex vivo expansion and reinfusion of CD4 T cells from HIV-infected adults.

Apoptosis↗
PubMed1997

Glutathione deficiency is associated with impaired survival in HIV disease.

Glutathione (GSH), a cysteine-containing tripeptide, is essential for the viability and function of virtually all cells. In vitro studies showing that low GSH levels both promote HIV expression and impair T cell function suggested a link between GSH depletion and HIV disease progression. Clinical studies presented here directly demonstrate that low GSH levels predict poor survival in otherwise indistinguishable HIV-infected subjects. Specifically, we show that GSH deficiency in CD4 T cells from such subjects is associated with markedly decreased survival 2-3 years after baseline data collection (Kaplan-Meier and logistic regression analyses, P < 0.0001 for both analyses). This finding, supported by evidence demonstrating that oral administration of the GSH prodrug N-acetylcysteine replenishes GSH in these subjects and suggesting that N-acetylcysteine administration can improve their survival, establishes GSH deficiency as a key determinant of survival in HIV disease. Further, it argues strongly that the unnecessary or excessive use of acetaminophen, alcohol, or other drugs known to deplete GSH should be avoided by HIV-infected individuals.

Acetylcysteine↗
PubMed1997

Dynamics of fine T-cell subsets during HIV disease and after thymic ablation by mediastinal irradiation.

The T-cell compartment is considerably more complex than just CD4 and CD8 T cells. Indeed, we can identify dozens of functionally and phenotypically distinct subsets within the peripheral blood of humans. These subsets are differentially affected in diseases which may underly some of the functional defects attributable to the disease. In HIV disease, all thymic-derived T-cell populations are gradually lost at identical rates during late-stage disease progression, while unusual, perhaps extrathymically-derived T cells expand. This expansion may reflect an attempt on the part of the immune system to compensate for the significant insult of HIV infection to the host: the abrogation of normal thymopoiesis and T-cell homeostasis.

HIV Infections↗
PubMed1996

Enzyme-generated intracellular fluorescence for single-cell reporter gene analysis utilizing Escherichia coli beta-glucuronidase.

We report the development of a new fluorescence-activated cell sorter (FACS)-based reporter gene system utilizing the enzymatic activity of the E. coli beta-glucuronidase (gus) gene. When loaded with the Gus substrate fluorescein-di-beta-D-glucuronide (FDGlcu), individual mammalian cells expressing and translating gus mRNA liberate sufficient levels of intracellular fluorescein for quantitative analysis by flow cytometry. This assay can be used to FACS sort viable cells based on Gus enzymatic activity, and the efficacy of the assay can be measured independently by using a fluorometric lysate assay. Furthermore, both the beta-glucuronidase and the previously described E. coli beta-galactosidase enzymes have high specificities for their cognate substrates, allowing each reporter gene to be measured by FACS independently.

Animals↗
PubMed1996

Cy7PE and Cy7APC: bright new probes for immunofluorescence.

We demonstrate the utility of indotricarbocyanine (Cy7) conjugates of the phycobiliproteins phycoerythrin (PE) and allophycocyanin (APC) in flow cytometry. This is the first demonstration of the use of an APC tandem dye for fluorescence measurements. These resonance energy transfer tandem dyes can be excited by the phycobiliprotein-specific excitation wavelengths and fluoresce at wavelengths above 780 nm. The tandem dyes, when conjugated to antibodies, are suitable for flow cytometry and other immunofluorescence applications. These conjugates are easily detectable above the very low autofluorescence in this part of the spectrum. Indeed, the Cy7-conjugated PE tandem (Cy7PE) has a "brightness" (fluorescence signal over cellular autofluorescence) comparable to that of fluorescein, and the Cy7APC tandem has a "brightness" comparable to that of APC. These tandems are also easily distinguished from other commonly used fluorophores, making them suitable for high-order multiparametric analysis. We show an example of six-color immunofluorescence analysis by flow cytometry, simultaneously measuring fluorescences from fluorescein, PE, Cy5PE, Texas red, APC, and Cy7APC.

Antigens, CD↗
PubMed1996

Changes in antigen densities on leukocyte subsets correlate with progression of HIV disease.

In a cross-sectional study of 154 HIV-infected and 33 uninfected healthy adults, we show that characteristic changes in the levels of expression of leukocyte surface antigens occur in the HIV-infected individuals. These changes, which collectively occur on virtually every leukocyte subset, are specific: a particular antigen may increase or decrease on one subset of PBMC but remain constant on another. Furthermore, within any particular subset, the levels of one or more antigens may change, while the levels of other surface antigens on the same cells remain constant. Some of these antigens density changes have been noted before, e.g. increased CD20 on B cells, and increased CD38 and HLA-DR on CD8 T cells. However, the multiparameter flow cytometry methodology used here reveals changes in a substantially larger number of surface markers, some of which are restricted to fine subsets of PBMC, such as naive or memory T cell subsets. For many of these antigens, the change in expression correlates with absolute CD4 counts >500/microl; others differ only in those with counts >100microl. The changes in antigen densities we observed on B and T cells are consistent with the observation of a persistent quasi-activated state of these cells in HIV-infected individuals. Similarly, the altered expression of the signal-transducing molecules CD7 and CD16 that we demonstrated for NK cells may correlate with the functional defects previously demonstrated in NK cells. Thus, measurements of antigen densities such as those demonstrated here may provide surrogate markers for the altered functional capacities of PBMC subsets in HIV-infected individuals, and may thereby provide a much simpler assay for immunocompetence than in vitro functional assays.

Adult↗
PubMed1996

Elevation of plasma thioredoxin levels in HIV-infected individuals.

Thioredoxin (Trx), a ubiquitous protein intimately involved in redox and protein disulfide reductions, has been shown to be released from cells and to have cytokine-like activities. In addition, Trx has been implicated in the redox regulation of immunological responses and shown to be deficient in tissues from AIDS patients. In studies presented here, plasma Trx levels were measured by ELISA in plasma samples from HIV-infected individuals (n = 136) and HIV-negative controls (n = 47). To account for the release of Trx into plasma due to hemolysis, the Trx measurements were corrected according to the level of hemoglobin in the plasma sample. Data presented show that, in contrast to tissue Trx levels, corrected plasma Trx levels are significantly higher in HIV-infected individuals than in controls (P < 0.0001). Furthermore, approximately 25% of the HIV-infected individuals studied have plasma Trx levels greater than the highest levels found in controls (37 ng/ml). Detailed multiparameter FACS analysis of peripheral blood mononuclear cells (PBMC) from the infected individuals demonstrates that those with higher plasma Trx levels (37 ng/ml or greater) tend to have lower overall CD4 counts. In addition, increases in plasma Trx levels correlate with decreases in monochlorobimane staining (indicative of lower intracellular glutathione levels in PBMC) and with changes in surface antigen expression (CD62L, CD38 and CD20) that occur in the later stages of HIV infection. These correlations suggest that elevation of plasma Trx levels may be an important component of advanced HIV disease, perhaps related to the oxidative stress that often occurs at this stage.

Antigens, CD↗
PubMed1995

ET-18-OCH3 inhibits nuclear factor-kappa B activation by 12-O-tetradecanoylphorbol-13-acetate but not by tumor necrosis factor-alpha or interleukin 1 alpha.

1-O-Octadecyl-2-O-methyl-rac-glycero-3-phosphocholine (ET-18-OCH3) is a synthetic diether phospholipid that is competitive with phosphatidylserine binding to the regulatory domain of protein kinase C (PKC). Our previous studies indicate that the selective inhibition of tumor cell growth by ET-18-OCH3 may be due to altered signal transduction mechanisms, including the inhibition of PKC. To further define the mechanism of action of ET-18-OCH3, we have used it to study the role of PKC in regulation of the transcription factor NF-kappa B, which is activated by diverse stimuli. In the 293.27.2 human kidney cell line, as in hematopoietic cells of all lineages, NF-kappa B is stimulated by 12-O-tetradecanoylphorbol-13-acetate (TPA), tumor necrosis factor-alpha (TNF-alpha), and interleukin-1 alpha (IL-1 alpha). The response to either TNF-alpha or IL-1 alpha is synergistically enhanced by TPA. However, the regulatory mechanisms and signal transduction systems responsible for NF-kappa B activation in response to these different stimuli have not been determined in detail. We have used ET-18-OCH3 and auranofin, which inhibit PKC by different mechanisms, to assess the role of PKC in NF-kappa B activation. ET-18-OCH3 markedly inhibits TPA-induced NF-kappa B activation, as measured by HIV long terminal repeat-directed expression of beta-galactosidase. The IC50 for inhibition by ET-18-OCH3 is approximately 2 microM, a noncytotoxic concentration. Inhibition of TPA-induced NF-kappa B activation was dependent upon preincubation with ET-18-OCH3, and the drug was active at approximately 2 mol% of total cellular phospholipid. ET-18-OCH3 did not inhibit NF-kappa B activation by either TNF-alpha or IL-1 alpha, indicating that there are multiple distinct signal transduction pathways leading to activation of NF-kappa B. We have confirmed these results using auranofin, an antirheumatic drug that is a specific PKC inhibitor interacting with the catalytic domain. Like ET-18-OCH3, auranofin blocked NF-kappa B activation by TPA but not by TNF-alpha or IL-1 alpha. Also like the ether lipid, auranofin only partially blocked the synergy exhibited by TPA and TNF-alpha. To confirm the role of NF-kappa B in this response, we measured NF-kappa B by electrophoretic mobility shift assay. Both ET-18-OCH3 and auranofin inhibited cellular induction of the active NF-kappa B complex in response to TPA but not in response to TNF-alpha.(ABSTRACT TRUNCATED AT 400 WORDS)

Antineoplastic Agents↗
PubMed1995

Heterogeneous calcium flux in peripheral T cell subsets revealed by five-color flow cytometry using log-ratio circuitry.

Calcium flux measurements of different subpopulations of cells by flow cytometry are important in understanding complex interactions in the immune system. This paper discusses the use of the difference of Log signals as a preferred method for obtaining this information simultaneously with other immunofluorescence parameters. We describe simple modifications to a commercial instrument that enables the measurement of calcium flux in addition to three immunofluorescence parameters. Finally, we show an application of this technique to measuring calcium flux of T cell subsets in human blood. We show that different subsets of peripheral CD4 T cells have significantly different capabilities to flux calcium after CD3 stimulation. These differences are related to the functional capacities of the cells within these subsets.

Antigens, CD↗
PubMed1995

Altered representation of naive and memory CD8 T cell subsets in HIV-infected children.

CD8 T cells are divided into naive and memory subsets according to both function and phenotype. In HIV-negative children, the naive subset is present at high frequencies, whereas memory cells are virtually absent. Previous studies have shown that the overall number of CD8 T cells does not decrease in HIV-infected children. In studies here, we use multiparameter flow cytometry to distinguish naive from memory CD8 T cells based on expression of CD11a, CD45RA, and CD62L. With this methodology, we show that within the CD8 T cell population, the naive subset decreases markedly (HIV+ vs. HIV-, 190 vs. 370 cells/microliter; P < or = 0.003), and that there is a reciprocal increase in memory cells, such that the total CD8 T cell counts remained unchanged (800 vs. 860 cells/microliter; P < or = 0.76). In addition, we show that for HIV-infected children, the naive CD8 T cell and total CD4 T cell counts correlate (chi 2 P < or = 0.001). This correlated loss suggests that the loss of naive CD8 T cells in HIV infection may contribute to the defects in cell-mediated immunity which become progressively worse as the HIV disease progresses and CD4 counts decrease.

Actins↗
PubMed1995

CD8 naive T cell counts decrease progressively in HIV-infected adults.

We show here that CD8 naive T cells are depleted during the asymptomatic stage of HIV infection. Although overall CD8 T cell numbers are increased during this stage, the naive CD8 T cells are progressively lost and fall in parallel with overall CD4 T cell counts. In addition, we show that naive CD4 T cells are preferentially lost as total CD4 cell counts fall. These findings, presented here for adults, and in the accompanying study for children, represent the first demonstration that HIV disease involves the loss of both CD4 T cells and CD8 T cells. Furthermore, they provide a new insight into the mechanisms underlying the immunodeficiency of HIV-infected individuals, since naive T cells are required for all new T cell-mediated immune responses. Studies presented here also show that the well-known increase in total CD8 counts in most HIV-infected individuals is primarily due to an expansion of memory cells. Thus, memory CD8 T cells comprise over 80% of the T cells in PBMC from individuals with < 200 CD4/microliter, whereas they comprise roughly 15% in uninfected individuals. Since the naive and memory subsets have very different functional activities, this altered naive/memory T cell representation has significant consequences for the interpretation of data from in vitro functional studies.

Adult↗
PubMed1994

Glutathione precursor and antioxidant activities of N-acetylcysteine and oxothiazolidine carboxylate compared in in vitro studies of HIV replication.

N-Acetyl-L-cysteine (NAC) and L-2-oxothiazolidine 4-carboxylate (OTC) are pro-GSH drugs that been proposed for AIDS therapy. In this article we compare the antiviral activities of these compounds in various in vitro HIV infection models. Although both compounds blocked cytokine induction of HIV in acute and chronic infection models, and in HIV-LTR reporter cell systems, NAC was far more effective than OTC, even at suboptimal doses. To test whether this difference is due to GSH conversion efficacies of these compounds, we measured GSH restoration by NAC or OTC in GSH-depleted peripheral blood mononuclear cells (PBMCs), using flow cytometry. In isolated PBMCs, NAC fully replenishes depleted intracellular GSH whereas OTC only minimally replenishes GSH. This ability to replenish GSH in vitro and its ability to scavenge free radicals directly explain why NAC has more potent antiviral activities in vitro.

Acetylcysteine↗