Robust Anti-Leukemia CD4+ and CD8+ T Cell Responses in CML Patients Treated with Imatinib Mesylate.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2199-2199
Author(s):  
Christiane I.-U. Chen ◽  
Alexandre Johannsen ◽  
Wesley Witteles ◽  
Holden T. Maecker ◽  
Peter P. Lee
Keyword(s):  
T Cell ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Leukemic Cells ◽  
T Cell Clones ◽  
Cell Responses ◽  
Cell Clones ◽  
Tnf Α ◽  
Ifn Γ ◽  
Cytogenetic Remission

Abstract Imatinib mesylate, a selective inhibitor of the bcr/abl tyrosine kinase, has revolutionized the treatment of CML and is the first-line therapy for most patients. Most CML patients in chronic phase achieve hematologic remission under treatment with imatinib, with up to 70% also achieving cytogenetic remission. However, imatinib therapy is not curative, as patients who discontinue the drug invariably relapse. Thus, the need to find alternate, potentially curative therapies remains. Low levels of CD8+ T cell responses to certain HLA restricted peptides have been detected in CML patients after successful treatment. To determine, if CML patients in remission on imatinib develop and sustain anti-leukemia CD4+ or CD8+ T cell responses, blood samples from patients before and several time points after treatment were collected and analyzed. Pre-treatment samples were utilized as sources of autologous leukemic cells to detect anti-leukemia T cell responses in post-treatment remission samples. Autologous leukemic samples alone and remission samples alone served as controls. In 7 of the 14 patients investigated, significant IFN-γ responses (p<0.01) in ELISPOT assay were detectable when patients achieved cytogenetic remission, and peaked at 10–15 months (median 36 SFCs, range 26–71 SFCs), before they slowly decreased (up to 46 months post-treatment) to levels similar to those from leukemic samples alone and remission samples alone (6 SFCs, range 0–13 SFCs). These results correlated with T cell responses in cytokine flow cytometry (TNF-α 1.4–40%, IFN-γ 1.0–6.6%, p<0.05), and showed a predominance for CD4+ T cells. Furthermore, TNF-α and IFN-γ production (p<0.05) was confirmed in CD4+ and CD8+ T cell clones generated in a remission sample from one patient using multiplex cytokine assay: 6.43–37.90 pg/ml for TNF-α, 14.90–110.42 pg/ml for IFN-γ. CD8+ T cell clones (HLA-A0201+) were tested for reactivity against HLA-A0201 restricted peptides derived from leukemia associated antigens proteinase 3, Wilms tumor 1 and bcr/abl, as well as tumor associated antigens p53, p68, and human telomerase (hTERT) in IFN-γ ELISPOT assays. No IFN-γ responses were detected in the CD8+ T cell clones when stimulated with the peptides compared to stimulation with an irrelevant peptide (0–15 SFCs, p=0.55), suggesting that these clones react to as yet to be defined leukemia associated antigens. Together, these data show that CD4+ T cells play an important role in anti-leukemia immune responses in patients in remission (sustained over time) and might contribute to killing of leukemic cells, possibly via TNF-α. Banked autologous leukemic cells could be used for vaccination of CML patients in order to enhance anti-leukemia T cell responses and may, in combination with imatinib, lead to eradication of residual leukemic cells with a durable cure.

scholarly journals Differential Functional Avidity of Dengue Virus-Specific T-Cell Clones for Variant Peptides Representing Heterologous and Previously Encountered Serotypes

2007 ◽  
Vol 81 (18) ◽  
pp. 10081-10091 ◽  
Author(s):  
Allison Imrie ◽  
Janet Meeks ◽  
Alexandra Gurary ◽  
Munkhzul Sukhbataar ◽  
Paul Kitsutani ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Dengue Virus ◽  
Severe Disease ◽  
T Cell Clones ◽  
Cell Responses ◽  
Cell Clones ◽  
Tnf Α ◽  
Dengue Virus Serotypes ◽  
Ifn Γ

ABSTRACT Proinflammatory cytokines secreted by memory CD8+ and CD4+ T cells are thought to play a direct role in the pathogenesis of dengue virus infection by increasing vascular permeability and thereby inducing the pathophysiologic events associated with dengue hemorrhagic fever and dengue shock syndrome. Severe disease is frequently observed in the setting of secondary infection with heterologous dengue virus serotypes, suggesting a role for cross-reactive memory T cells in the immunopathogenesis of severe disease. We used a large panel of well-characterized dengue virus-specific CD8+ T-cell clones isolated from Pacific Islanders previously infected with dengue virus 1 to examine effector memory function, focusing on a novel dominant HLA-B*5502-restricted NS5329-337 epitope, and assessed T-cell responses to stimulation with variant peptides representing heterologous serotypes. Variant peptides were differentially recognized by dengue virus 1-specific effector CD8+ cytotoxic T lymphocytes (CTL) in a heterogeneous and clone-specific manner, in which cytolytic function and cytokine secretion could be enhanced, diminished, or abrogated compared with cognate peptide stimulation. Dengue virus-specific CTL stimulated with cognate and variant peptides demonstrated a cytokine response hierarchy of gamma IFN (IFN-γ) > tumor necrosis factor alpha (TNF-α) > interleukin-2 (IL-2), and a subset of clones also produced IL-4 and IL-6. Individual clones demonstrated greater avidity for variant peptides representing heterologous serotypes, including serotypes previously encountered by the subject, and IFN-γ and TNF-α secretion was enhanced by stimulation with these heterologous peptides. Altered antiviral T-cell responses in response to stimulation with heterologous dengue virus serotypes have implications for control of virus replication and for disease pathogenesis.

scholarly journals Characterization of T-Cell Responses to SMX and SMX-NO in Co-Trimoxazole Hypersensitivity Patients Expressing HLA-B*13:01

2021 ◽  
Vol 12 ◽  
Author(s):  
Jirawat Pratoomwun ◽  
Paul Thomson ◽  
Kanoot Jaruthamsophon ◽  
Rawiporn Tiyasirichokchai ◽  
Pimonpan Jinda ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Antigen Processing ◽  
T Cell Responses ◽  
Stevens Johnson Syndrome ◽  
Antigen Specificity ◽  
T Cell Clones ◽  
Cell Responses ◽  
Cell Clones ◽  
Ifn Γ

HLA-B*13:01-positive patients in Thailand can develop frequent co-trimoxazole hypersensitivity reactions. This study aimed to characterize drug-specific T cells from three co-trimoxazole hypersensitive patients presenting with either Stevens-Johnson syndrome or drug reaction with eosinophilia and systemic symptoms. Two of the patients carried the HLA allele of interest, namely HLA-B*13:01. Sulfamethoxazole and nitroso sulfamethoxazole specific T cell clones were generated from T cell lines of co-trimoxazole hypersensitive HLA-B*13:01-positive patients. Clones were characterized for antigen specificity and cross-reactivity with structurally related compounds by measuring proliferation and cytokine release. Surface marker expression was characterized via flow cytometry. Mechanistic studies were conducted to assess pathways of T cell activation in response to antigen stimulation. Peripheral blood mononuclear cells from all patients were stimulated to proliferate and secrete IFN-γ with nitroso sulfamethoxazole. All sulfamethoxazole and nitroso sulfamethoxazole specific T cell clones expressed the CD4+ phenotype and strongly secreted IL-13 as well as IFN-γ, granzyme B and IL-22. No secretion of IL-17 was observed. A number of nitroso sulfamethoxazole-specific clones cross-reacted with nitroso dapsone but not sulfamethoxazole whereas sulfamethoxazole specific clones cross-reacted with nitroso sulfamethoxazole only. The nitroso sulfamethoxazole specific clones were activated in both antigen processing-dependent and -independent manner, while sulfamethoxazole activated T cell responses via direct HLA binding. Furthermore, activation of nitroso sulfamethoxazole-specific, but not sulfamethoxazole-specific, clones was blocked with glutathione. Sulfamethoxazole and nitroso sulfamethoxazole specific T cell clones from hypersensitive patients were CD4+ which suggests that HLA-B*13:01 is not directly involved in the iatrogenic disease observed in co-trimoxazole hypersensitivity patients.

scholarly journals Selection of T Cell Clones Expressing High-Affinity Public TCRs within Human Cytomegalovirus-Specific CD8 T Cell Responses

2005 ◽  
Vol 175 (9) ◽  
pp. 6123-6132 ◽  
Author(s):  
Lydie Trautmann ◽  
Marie Rimbert ◽  
Klara Echasserieau ◽  
Xavier Saulquin ◽  
Bérangère Neveu ◽  
...  
Keyword(s):  
T Cell ◽  
Human Cytomegalovirus ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
T Cell Clones ◽  
Cell Responses ◽  
High Affinity ◽  
Cell Clones ◽  
Selection Of

scholarly journals Assessment of the Phenotype and Functionality of Porcine CD8 T Cell Responses following Vaccination with Live Attenuated Classical Swine Fever Virus (CSFV) and Virulent CSFV Challenge

2013 ◽  
Vol 20 (10) ◽  
pp. 1604-1616 ◽  
Author(s):  
Giulia Franzoni ◽  
Nitin V. Kurkure ◽  
Daniel S. Edgar ◽  
Helen E. Everett ◽  
Wilhelm Gerner ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Classical Swine Fever Virus ◽  
T Cell Responses ◽  
Classical Swine Fever ◽  
Cd8 T Cell ◽  
Cell Responses ◽  
Tnf Α ◽  
Ifn Γ

ABSTRACTVaccination with live attenuated classical swine fever virus (CSFV) induces solid protection after only 5 days, which has been associated with virus-specific T cell gamma interferon (IFN-γ) responses. In this study, we employed flow cytometry to characterize T cell responses following vaccination and subsequent challenge infections with virulent CSFV. The CD3+CD4−CD8hiT cell population was the first and major source of CSFV-specific IFN-γ. A proportion of these cells showed evidence for cytotoxicity, as evidenced by CD107a mobilization, and coexpressed tumor necrosis factor alpha (TNF-α). To assess the durability and recall of these responses, a second experiment was conducted where vaccinated animals were challenged with virulent CSFV after 5 days and again after a further 28 days. While virus-specific CD4 T cell (CD3+CD4+CD8α+) responses were detected, the dominant response was again from the CD8 T cell population, with the highest numbers of these cells being detected 14 and 7 days after the primary and secondary challenges, respectively. These CD8 T cells were further characterized as CD44hiCD62L−and expressed variable levels of CD25 and CD27, indicative of a mixed effector and effector memory phenotype. The majority of virus-specific IFN-γ+CD8 T cells isolated at the peaks of the response after each challenge displayed CD107a on their surface, and subpopulations that coexpressed TNF-α and interleukin 2 (IL-2) were identified. While it is hoped that these data will aid the rational design and/or evaluation of next-generation marker CSFV vaccines, the novel flow cytometric panels developed should also be of value in the study of porcine T cell responses to other pathogens/vaccines.

Ex-Vivo Characterization of Polyclonal Memory CD8+ T-Cell Responses to PRAME-Specific Peptides in Patients with Acute Leukemia and Chronic Myeloid Leukemia

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2910-2910
Author(s):  
Katayoun Rezvani ◽  
Agnes S. M. Yong ◽  
Abdul Tawab ◽  
Behnam Jafarpour ◽  
Rhoda Eniafe ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Myeloid Leukemia ◽  
Ex Vivo ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
High Avidity ◽  
Cell Responses ◽  
Ifn Γ

Abstract PRAME (Preferentially expressed antigen of melanoma) is aberrantly expressed in hematological malignancies and may be a useful target for immunotherapy in leukemia. We studied CD8+ T-cell responses to four HLA-A*0201-restricted PRAME-derived epitopes (PRA100, PRA142, PRA300, PRA425) in HLA-A*0201-positive patients with acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), chronic myeloid leukemia (CML) and healthy donors, using PRA300/HLA-A*0201 tetramer staining, intracellular cytokine (IC) assay and ex-vivo and cultured ELISPOT analysis. CD8+ T-cells recognizing PRAME peptides were detected directly ex-vivo in 4/10 ALL, 6/10 AML, 3/10 CML patients and 3/10 donors. The frequency of PRAME-specific CD8+ T-cells was greater in patients with AML, CML and ALL than in healthy controls. All peptides were immunogenic in patients, whilst PRA300 was the only immunogenic peptide in donors. High PRAME expression in patient peripheral blood mononuclear cells was associated with responses to two or more PRAME epitopes (4/7 vs. 0/23 in individuals with low PRAME expression, P = 0.001), suggesting a PRAME-driven T-cell response. In 2 patients studied PRA300/HLA-A*0201+ CD8+T-cells were found to be a mixture of effector and central memory phenotypes. To determine the functional avidity of the PRAME T-cell response, the response of CD8+ T-cells to stimulation with 2 concentrations of peptide was measured by IC-IFN-γ staining. High-avidity CD8+ T-cells were defined as those capable of producing IFN-γ in response to the lower concentration of peptide (0.1μM), while low-avidity CD8+ T-cells were those that only produced IFN-γ in response to the higher concentration of peptide (10 μM). Both high and low-avidity CD8+ T-cell responses could be detected for all peptides tested (median 1.05, 0.90, 0.52, 0.40 high/lowavidity ratios for PRA100, PRA142, PRA300 and PRA425 respectively). In patients with high PRAME expression (&gt;0.001 PRAME/ABL) low-avidity CD8+ T-cell responses to PRAME peptides were more prominent than high-avidity responses, suggesting selective deletion of high-avidity T-cells. In contrast, in some patients with levels &lt;0.001 PRAME/ABL, we could detect the presence of high-avidity CD8+ T-cell responses to PRAME. PRAME-specific CD8+ T-cells were further characterized by IC staining for IL-2, IL-4 and IL-10 production and CD107a mobilization (as a marker of cytotoxicity). Following stimulation with the relevant PRAME peptide, there was no significant production of IL-2, IL-4 or IL-10, suggesting a Tc1 effector response but no significant CD107a mobilization was detected despite significant CD107a mobilization in the same patient in response to CMVpp65495. This finding suggests that patients with leukemia have a selective functional impairment of PRAME-specific CD8+ T-cells, consistent with PRAME-specific T cell exhaustion. However, PRAME-specific T-cells were readily expanded in the presence of cytokines in short-term cultures in-vitro to produce IFN-γ, suggesting that it may be possible to improve the functional capacity of PRAME-specific T-cells for therapeutic purposes. These results provide evidence for spontaneous T-cell reactivity against multiple epitopes of PRAME in ALL, AML and CML and support the usefulness of PRAME as a target for immunotherapy in leukemia. The predominance of low-avidity PRAME-specific CD8+ T-cells suggests that achievement of a state of minimal residual disease may be required prior to peptide vaccination to augment T-cell immune surveillance.

The Response to Repeated Vaccination with PR1 and WT1 Peptides Admixed in Montanide Adjuvant Is Transient and Fails to Induce Sustained Anti-Leukemia Responses in Patients with Myeloid Malignancies.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4096-4096
Author(s):  
Katayoun Rezvani ◽  
Agnes S. M. Yong ◽  
Stephan Mielke ◽  
Behnam Jafarpour ◽  
Bipin N. Savani ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cell Response ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
T Cell Response ◽  
Gm Csf ◽  
Cell Responses ◽  
Ifn Γ

Abstract Abstract 4096 Poster Board III-1031 We previously demonstrated the immunogenicity of a combined vaccine approach employing two leukemia-associated antigenic peptides, PR1 and WT1 (Rezvani Blood 2008). Eight patients with myeloid malignancies received one subcutaneous 0.3 mg and 0.5 mg dose each of PR1 and WT1 vaccines in Montanide adjuvant, with 100 μg of granulocyte-macrophage colony-stimulating factor (GM-CSF). CD8+ T-cell responses against PR1 or WT1 were detected in all patients as early as 1 week post-vaccination. However, responses were only sustained for 3-4 weeks. The emergence of PR1 or WT1-specific CD8+ T-cells was associated with a significant but transient reduction in minimal residual disease (MRD) as assessed by WT1 expression, suggesting a vaccine-induced anti-leukemia response. Conversely, loss of response was associated with reappearance of WT1 transcripts. We hypothesized that maintenance of sustained or at least repetitive responses may require frequent boost injections. We therefore initiated a phase 2 study of repeated vaccination with PR1 and WT1 peptides in patients with myeloid malignancies. Five patients with acute myeloid leukemia (AML) and 2 patients with myelodysplastic syndrome (MDS) were recruited to receive 6 injections at 2 week intervals of PR1 and WT1 in Montanide adjuvant, with GM-CSF as previously described. Six of 7 patients completed 6 courses of vaccination and follow-up as per protocol, to monitor toxicity and immunological responses. Responses to PR1 or WT1 vaccine were detected in all patients after only 1 dose of vaccine. However, additional boosting did not further increase the frequency of PR1 or WT1-specific CD8+ T-cell response. In 4/6 patients the vaccine-induced T-cell response was lost after the fourth dose and in all patients after the sixth dose of vaccine. To determine the functional avidity of the vaccine-induced CD8+ T-cell response, the response of CD8+ T-cells to stimulation with 2 concentrations of PR1 and WT1 peptides (0.1 and 10 μM) was measured by IC-IFN-γ staining. Vaccination led to preferential expansion of low avidity PR1 and WT1 specific CD8+ T-cell responses. Three patients (patients 4, 6 and 7) returned 3 months following the 6th dose of PR1 and WT1 peptide injections to receive a booster vaccine. Prior to vaccination we could not detect the presence of PR1 and WT1 specific CD8+ T-cells by direct ex-vivo tetramer and IC-IFN-γ assay or with 1-week cultured IFN-γ ELISPOT assay, suggesting that vaccination with PR1 and WT1 peptides in Montanide adjuvant does not induce memory CD8+ T-cell responses. This observation is in keeping with recent work in a murine model where the injection of minimal MHC class I binding peptides derived from self-antigens mixed with IFA adjuvant resulted in a transient effector CD8+ T cell response with subsequent deletion of these T cells and failure to induce CD8+ T cell memory (Bijker J Immunol 2007). This observation can be partly explained by the slow release of vaccine peptides from the IFA depot without systemic danger signals, leading to presentation of antigen in non-inflammatory lymph nodes by non-professional antigen presenting cells (APCs). An alternative explanation for the transient vaccine-induced immune response may be the lack of CD4+ T cell help. In summary these data support the immunogenicity of PR1 and WT1 peptide vaccines. However new approaches will be needed to induce long-term memory responses against leukemia antigens. To avoid tolerance induction we plan to eliminate Montanide adjuvant and use GM-CSF alone. Supported by observations that the in vivo survival of CD8+ T-effector cells against viral antigens are improved by CD4+ helper cells, we are currently attempting to induce long-lasting CD8+ T-cell responses to antigen by inducing CD8+ and CD4+ T-cell responses against class I and II epitopes of WT1 and PR1. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Graft-versus-leukemia effects associated with detectable Wilms tumor-1–specific T lymphocytes after allogeneic stem-cell transplantation for acute lymphoblastic leukemia

Blood ◽  
2007 ◽  
Vol 110 (6) ◽  
pp. 1924-1932 ◽  
Author(s):  
Katayoun Rezvani ◽  
Agnes S. M. Yong ◽  
Bipin N. Savani ◽  
Stephan Mielke ◽  
Keyvan Keyvanfar ◽  
...  
Keyword(s):  
Stem Cell ◽  
T Cell ◽  
Cd8 T Cells ◽  
Wilms Tumor ◽  
Lymphoblastic Leukemia ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Cell Responses ◽  
Graft Versus Leukemia ◽  
Ifn Γ

Abstract To determine whether the leukemia-associated Wilms tumor antigen (WT1) contributes to a graft-versus-leukemia (GVL) effect after allogeneic stem-cell transplantation (SCT) for acute lymphoblastic leukemia (ALL), we studied CD8+ T-cell responses to WT1 in 10 human lymphocyte antigen (HLA)–A*0201–positive ALL patients during the early phase of immune recovery after SCT (days 30-120). Seven of 10 patients had detectable WT1 expression in their peripheral blood (PB) before SCT by quantitative reverse-transcription polymerase chain reaction. Using WT1/HLA-A*0201 tetramers and intracellular interferon-γ (IFN-γ) staining, WT1+ CD8+ T-cell responses after SCT were found only in patients with detectable WT1 expression before SCT (5 of 7 vs. 0 of 3; P < .05). To monitor the kinetics of WT1+ CD8+ T-cell responses and disease regression after SCT, absolute WT1+ CD8+ T-cell numbers and WT1 expression were studied for each time point. The emergence of WT1+ CD8+ T cells was associated with a decrease in WT1 expression, suggesting a WT1-driven GVL effect. Loss of WT1+ CD8+ T-cell responses was associated with reappearance of WT1 transcripts, consistent with a molecular relapse (P < .001). WT1+ CD8+ T cells had a predominantly effector–memory phenotype (CD45RO+ CD27−CD57+) and produced IFN-γ. Our results support the immunogenicity of WT1 after SCT for ALL and highlight the potential for WT1 vaccines to boost GVL after SCT for ALL.

scholarly journals Functional Characterization and Modulation of Cytokine Production by CD8+ T Cells from Human Immunodeficiency Virus-Infected Individuals

Blood ◽  
1997 ◽  
Vol 89 (10) ◽  
pp. 3672-3681 ◽  
Author(s):  
Enrico Maggi ◽  
Roberto Manetti ◽  
Francesco Annunziato ◽  
Lorenzo Cosmi ◽  
Maria Grazia Giudizi ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cd8 T Cell ◽  
T Cell Clones ◽  
Cell Clones ◽  
Immunodeficiency Virus ◽  
Ifn Γ ◽  
Hiv Seropositive

CD8+ T-cell clones were generated from peripheral blood mononuclear cells (PBMC) of three human immunodeficiency virus (HIV)-seronegative individuals and six HIV-seropositive individuals and assessed for their cytokine secretion profile, cytolytic potential, and chemokine production. While the great majority of CD8+ T-cell clones generated from HIV-seronegative individuals produced interferon (IFN)-γ, but not interleukin-4 (IL-4), that is a type 1 cytotoxic (Tc1) profile, high numbers of CD8+ T-cell clones generated from HIV-seropositive individuals produced IL-4 in addition to IFN-γ or IL-4 alone, thus showing a type 0 cytotoxic (Tc0)- or a type 2 cytotoxic (Tc2) profile, respectively. Tc0/Tc2 cells displayed lower cytolytic activity than Tc1 cells, including a reduced ability to lyse autologous targets pulsed with HIV or HIV peptides. By contrast, the production of chemokines RANTES and macrophage inflammatory protein-1α was comparable in Tc1, Tc0, and Tc2 clones irrespective of whether they were derived from HIV-seronegative or HIV-seropositive individuals. When CD8+ T-cell clones were generated from PBMC cultures of HIV-seronegative individuals conditioned with IL-4 plus an anti–IL-12 antibody (Ab), a shift towards the Tc0/Tc2-like profile was observed. Conversely, the addition to PBMC cultures of IL-12 plus an anti – IL-4 Ab shifted the differentiation of CD8+ T cells from HIV-infected individuals towards the Tc1-like profile, whereas IL-12 or anti–IL-4 Ab alone had a lower Tc1-promoting effect. Irradiated PBMC from HIV-infected individuals, used as feeder cells, shifted the differentiation of CD8+ T cells from a healthy HIV-seronegative individual towards the Tc0/Tc2-like profile. On the other hand, a shift towards the Tc1-like profile was noted in CD8+ T-cell clones generated from the skin specimens of two HIV-seropositive patients with Kaposi's sarcoma, successfully treated with IFN-α, in comparison to CD8+ clones generated from the same skin areas before treatment. The IFN-α–induced Tc1 shift could be prevented by the incubation of skin-infiltrating CD8+ T cells with IL-4 before cloning. Taken together, these data indicate that both defective production of IL-12 and abnormal IL-4 production in bulk PBMC populations of HIV-infected individuals may contribute to the development of high numbers of CD8+ T-cell clones showing a Tc0/Tc2-like phenotype and reduced cytolytic potential against HIV itself. They also suggest that the cytokine profile of CD8+ T-cell clones can be modulated by cytokines (or anticytokine Ab) both in vitro and in vivo.

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