The Levels and Patterns of Cytokines Produced by CD4 T Lymphocytes of BALB/c Mice Infected with Leishmania major by Inoculation into the Ear Dermis Depend on the Infectiousness and Size of the Inoculum

ABSTRACT The production of cytokines by CD4 lymph node T lymphocytes derived from BALB/c mice recently infected in the ear dermis with high (106 parasites) or low (103 parasites) doses of Leishmania major metacyclic promastigotes (MP) was examined over a 3-week period following inoculation. Results were compared with those obtained when mice were injected with less infectious parasite populations, namely, stationary-phase or log-phase promastigotes (LP). Cells were purified 16 h and 3, 8, and 19 days after inoculation, and the amounts of gamma interferon (IFN-γ) and interleukin-4 (IL-4) released in response to LACK (Leishmania homolog of receptors for activated C kinase) or total L. major antigens were assessed. We found that LACK-reactive T cells from mice inoculated with a high dose of parasites first produced IFN-γ and later on IL-4; the level of IFN-γ produced early by these cells was dependent upon the stage of the promastigotes inoculated, the highest level being reached with cells recovered from mice inoculated with the least infectious parasites, LP; sequential production of IFN-γ and then of IL-4 also characterized L. major antigen-reactive CD4 T cells, suggesting that the early production of IFN-γ does not impede the subsequent rise of IL-4 and finally the expansion of the parasites; after low-dose inoculation of MP, cutaneous lesions developed with kinetics similar to that of lesions induced after inoculation of 106 LP, but in this case CD4 T lymphocytes did not release IFN-γ or IL-4 in the presence of LACK and neither cytokine was produced in response to L. major antigens before the onset of lesion signs. These results suggest the existence of a discreet phase in terms of CD4 T-cell reactivity for at least the first 8 days following inoculation, a time period during which parasites are able to grow moderately. In conclusion, the levels and profiles of cytokines produced by Leishmania-specific CD4 T lymphocytes clearly depend on both the stage of differentiation and number of parasites used for inoculation.

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Populations of Human T Lymphocytes That Traverse the Vascular Endothelium Stimulated by Borrelia burgdorferi Are Enriched with Cells That Secrete Gamma Interferon

Infection and Immunity ◽

10.1128/iai.72.3.1530-1536.2004 ◽

2004 ◽

Vol 72 (3) ◽

pp. 1530-1536 ◽

Cited By ~ 11

Author(s):

Edna I. Gergel ◽

Martha B. Furie

Keyword(s):

T Cells ◽

T Lymphocytes ◽

Lyme Disease ◽

Borrelia Burgdorferi ◽

Vascular Endothelium ◽

Human Peripheral Blood ◽

Gamma Interferon ◽

Interleukin 4 ◽

Ifn Γ

ABSTRACT Some diseases are characterized by prevalence in the affected tissues of type 1 T lymphocytes, which secrete gamma interferon (IFN-γ) and other proinflammatory cytokines. For example, type 1 T cells predominate in the lesions of patients with Lyme disease, which is caused by the bacterium Borrelia burgdorferi. We used an in vitro model of the blood vessel wall to test the premise that the vascular endothelium actively recruits circulating type 1 T cells to such lesions. When T lymphocytes isolated from human peripheral blood were examined, the populations that traversed monolayers of resting human umbilical vein endothelial cells (HUVEC) or HUVEC stimulated by interleukin-1β or B. burgdorferi were markedly enriched for T cells that produced IFN-γ compared to the initially added population of T cells. No enrichment was seen for cells that produced interleukin-4, a marker for type 2 T lymphocytes. Very late antigen-4 and CD11/CD18 integrins mediated passage of the T cells across both resting and stimulated HUVEC, and the endothelium-derived chemokine CCL2 (monocyte chemoattractant protein 1) was responsible for the enhanced migration of T cells across stimulated HUVEC. These results suggest that the vascular endothelium may contribute to the selective accumulation of type 1 T cells in certain pathological lesions, including those of Lyme disease.

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Abstract 001: Axl Expression by CD4+ T Lymphocytes Promotes Salt-Dependent Hypertension

Hypertension ◽

10.1161/hyp.64.suppl_1.001 ◽

2014 ◽

Vol 64 (suppl_1) ◽

Author(s):

Kristine M Wadosky ◽

Sri N Batchu ◽

Angie Hughson ◽

Kathy Donlon ◽

Craig N Morrell ◽

...

Keyword(s):

Flow Cytometry ◽

T Cells ◽

T Cell ◽

T Lymphocytes ◽

Cd4 T Cells ◽

White Blood Cells ◽

Interleukin 4 ◽

Th2 Cells ◽

Salt Hypertension ◽

Ifn Γ

Introduction: Our laboratory has shown that Axl, a receptor tyrosine kinase, is important in both vascular and immune functions during deoxycorticosterone acetate (DOCA)-salt hypertension. We hypothesized that Axl activity specifically in T lymphocytes could explain the dependence of hypertension on Axl. Methods and Results: We did adoptive transfers of either Axl+/+ or Axl-/- CD4+ T cells to RAG1-/- mice that lack mature T cells. Once CD4+ T cell repopulations were confirmed, we induced DOCA-salt hypertension for 6 weeks. Systolic blood pressure (BP, mmHg) increased by 20±5 in Axl+/+RAG-/- mice after DOCA-salt, but Axl-/- RAG-/- mice had increases in BP by only 6+3 after 6 weeks of DOCA-salt. We isolated naïve CD4+ T cells from both Axl+/+ and Axl-/- littermates and primed them under either Th1 or Th2 polarizing conditions in culture. Production of interferon gamma (IFN-γ ng/mL) was significantly decreased (-23%, p<0.05) in Axl-/- (396±23) compared to Axl+/+ (512±42) under Th1-priming. However, Axl had no effect on interleukin 4 (IL-4, ng/mL) production under Th2 polarizing conditions. Intracellular staining of the Th1/Th2 cells with IFN-γ and IL-4 antibodies by flow cytometry confirmed expression of cytokines in culture media. Complete blood counts showed that Axl-/- mice had significantly lower white blood cells due to decreased numbers of lymphocytes (4.5±0.7x10 9 ) compared to Axl+/+ mice (7.8±0.7x10 9 ). We found a higher population of AnnexinV (marker of early apoptosis)-positive peripheral leukocytes in Axl-/- mice (10±1%) compared to Axl+/+ (4±1%) by flow cytometry; while the percentages of dead cells (~10%) were similar between Axl+/+ and Axl-/- mice. Conclusions: Altogether we show that expression of Axl by T cells drives salt-induced hypertension. The mechanism of Axl-dependent effects on T cells occurs via T-cell-dependent expression of the pro-inflammatory cytokine IFN-γ. In addition, Axl plays a role in inhibiting lymphocyte apoptosis in the circulation. Future work will focus on how Axl expression in T cells affects T cell-dependent vascular remodeling during hypertension.

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Enteral Immunization with Attenuated Recombinant Listeria monocytogenes as a Live Vaccine Vector: Organ-Dependent Dynamics of CD4 T Lymphocytes Reactive to a Leishmania major Tracer Epitope

Infection and Immunity ◽

10.1128/iai.71.3.1083-1090.2003 ◽

2003 ◽

Vol 71 (3) ◽

pp. 1083-1090 ◽

Cited By ~ 12

Author(s):

Hélène Saklani-Jusforgues ◽

Elisabeth Fontan ◽

Neirouz Soussi ◽

Geneviève Milon ◽

Pierre L. Goossens

Keyword(s):

T Cells ◽

Listeria Monocytogenes ◽

T Cell ◽

Cd4 T Cells ◽

Leishmania Major ◽

Cd4 T Cell ◽

Interleukin 4 ◽

Cell Immune Response ◽

Mesenteric Lymph Nodes ◽

Ifn Γ

ABSTRACT Listeria monocytogenes is considered as a potential live bacterial vector, particularly for the induction of CD8 T cells. The CD4 T-cell immune response triggered after enteral immunization of mice has not yet been thoroughly characterized. The dynamics of gamma interferon (IFN-γ)- and interleukin-4 (IL-4)-secreting CD4 T cells were analyzed after priming through intragastric delivery of an attenuated ΔactA recombinant L. monocytogenes strain expressing the Leishmania major LACK protein; a peptide of this protein, LACK158-173 peptide (pLACK), is a well-characterized CD4 T-cell target in BALB/c mice. Five compartments were monitored: Peyer's patches, mesenteric lymph nodes (MLN), spleen, liver, and blood. A single intragastric inoculation of ΔactA-LACK-LM in BALB/c mice led to colonization of the MLN and spleen at a significant level for at least 3 days. Efficient priming of IFN-γ-secreting pLACK-reactive CD4 T cells was observed in all tested compartments. Interestingly, IL-4-secreting pLACK-reactive CD4 T cells were detectable at day 6 or 7 only in blood and liver. The absence of translocation of viable bacteria through the intestinal epithelium after further ΔactA-LACK-LM inoculations was concomitant with the absence of an increase in the level of IFN-γ secreted by the MLN, blood, and splenic pLACK-reactive Th1 T cells, although the levels remained significantly above the basal level. No change in this population size was detected in the spleen. However, an increase in the number of intragastric inoculations had a clinical beneficial effect in L. major-infected BALB/c mice. L. monocytogenes thus presents the potential of an efficient vector for induction of CD4 T cells when administered by the enteral route.

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Listeria monocytogenes as a Short-Lived Delivery System for the Induction of Type 1 Cell-Mediated Immunity against the p36/LACK Antigen of Leishmania major

Infection and Immunity ◽

10.1128/iai.68.3.1498-1506.2000 ◽

2000 ◽

Vol 68 (3) ◽

pp. 1498-1506 ◽

Cited By ~ 35

Author(s):

Neirouz Soussi ◽

Geneviève Milon ◽

Jean-Hervé Colle ◽

Evelyne Mougneau ◽

Nicolas Glaichenhaus ◽

...

Keyword(s):

T Cells ◽

Listeria Monocytogenes ◽

Cd4 T Cells ◽

Leishmania Major ◽

Ex Vivo ◽

Experimental Models ◽

Interleukin 4 ◽

Cell Mediated Immunity ◽

Th1 Cells ◽

Ifn Γ

ABSTRACT Listeria monocytogenes has been used as an experimental live vector for the induction of CD8-mediated immune responses in various viral and tumoral experimental models. Susceptibility of BALB/c mice to Leishmania major infection has been correlated to the preferential development of Th2 CD4 T cells through an early production of interleukin 4 (IL-4) by a restricted population of CD4 T cells which react to a single parasite antigen, LACK (stands forLeishmania homologue of receptors for activated C kinase). Experimental vaccination with LACK can redirect the differentiation of CD4+ T cells towards the Th1 pathway if LACK is coadministrated with IL-12. As IL-12 is known to be induced by L. monocytogenes, we have tested the ability of a recombinant attenuated actA mutant L. monocytogenes strain expressing LACK to induce the development of LACK-specific Th1 cells in both B10.D2 and BALB/c mice, which are resistant and susceptible toL. major, respectively. After a single injection of LACK-expressing L. monocytogenes, IL-12/p40 transcripts showed a rapid burst, and peaks of gamma interferon (IFN-γ)-secreting LACK-specific Th1 cells were detected around day 5 in the spleens and livers of mice of both strains. These primed IFN-γ-secreting LACK-reactive T cells were not detected ex vivo after day 7 of immunization but could be recruited and detected 15 days later in the draining lymph node after an L. major footpad challenge. Although immunization of BALB/c mice with LACK-expressing L. monocytogenes did not change the course of the infection withL. major, immunized B10.D2 mice exhibited significantly smaller lesions than nonimmunized controls. Thus, our results demonstrate that, in addition of its recognized use for the induction of effector CD8 T cells, L. monocytogenes can also be used as a live recombinant vector to favor the development of potentially protective IFN-γ-secreting Th1 CD4 T lymphocytes.

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The In Vivo Impact of Human Regulatory T Cells on the Graft Versus Tumor Effect.

Blood ◽

10.1182/blood.v110.11.349.349 ◽

2007 ◽

Vol 110 (11) ◽

pp. 349-349 ◽

Cited By ~ 1

Author(s):

Tuna Mutis ◽

Henk Rozemuller ◽

Maarten E. Emmelot ◽

Tineke Aarts-Riemens ◽

Vivienne Verweij ◽

...

Keyword(s):

T Cells ◽

Regulatory T Cells ◽

Tumor Cells ◽

Cell Reactivity ◽

Human Pbmc ◽

Ifn Γ ◽

T Cell Reactivity ◽

The Impact

Abstract The curative Graft-vs-Tumor effect (GvT) of allogeneic Stem cell transplantation (SCT) is frequently complicated with life threatening Graft-vs-Host Disease (GvHD). In mice, prevention of GvHD, without abrogation of GvT is possible by co-transplantation of naturally occurring regulatory T cells (Tregs) with SC grafts. Consistent with these murine studies, we recently demonstrated that also human Tregs possess potent GvHD-downregulatory capacities in a xenogeneic(x) model, where x-GvHD is induced by infusion of autologous human T cells in RAG2−/−γc−/− mice (Mutis et al. Clin. Cancer Res.2006, 12: 5520–5525). Towards clinical application of Tregs, we now explored the impact of human Treg-administration on GvT in a bioluminescence imaging (BLI) based human-GvT model in the RAG2−/−γc−/− mice. In this model, mice inoculated with luciferase (LUC)-transduced human myeloma (MM) cell lines developed BLI-detectable, progressive, MM-like multifocal tumors exclusively in the bone marrow (BM). Full blown tumors were effectively eliminated by infusion of allogeneic human PBMC. This treatment also caused lethal x-GvHD as expected. In this setting, co-infusion of human PBMC with autologous, in vitro cultured Tregs at a 1:1 Treg: T effector cell ratio had no adverse effects on the development of GvT while significantly reducing the lethality of x-GvHD. In vitro analyses of sacrificed mice at day 21 revealed that administered Tregs homed to BM and spleen, significantly downregulated the total numbers of IFN-γ-producing CD4+ and CD8+ T cells responding to CD3 mediated signals, but had no downregulatory effect on the frequencies of IFN-γ-producing T cells responding to tumor cells. There was also no downregulation of cytotoxic activity against tumor cells in Treg-treated mice. Conclusively, these results showed that Tregs, at doses which are inhibitory for x-GvHD-inducing T cells, could maintain the GvT effect by allowing T cell reactivity against tumor cells. Human Tregs thus still hold promise as attractive cellular tools for separating GvT from GvHD.

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Interleukin-4 Receptor Alpha-Deficient BALB/c Mice Show an Unimpaired T Helper 2 Polarization in Response to Leishmania major Infection

Infection and Immunity ◽

10.1128/iai.68.4.1773-1780.2000 ◽

2000 ◽

Vol 68 (4) ◽

pp. 1773-1780 ◽

Cited By ~ 58

Author(s):

Markus Mohrs ◽

Christoph Holscher ◽

Frank Brombacher

Keyword(s):

T Cells ◽

Leishmania Major ◽

Interleukin 4 ◽

Cell Phenotype ◽

T Helper ◽

T Helper 2 ◽

Receptor Alpha ◽

Th2 Polarization ◽

Ifn Γ ◽

Th2 Development

ABSTRACT We recently generated interleukin-4 (IL-4) receptor alpha-deficient (IL-4Rα−/−) BALB/c mice and showed evidence for a protective role of IL-13-mediated functions in leishmaniasis. In this study, we investigated the IL-4 expression and T helper 2 (Th2) development in Leishmania major-infected IL-4Rα−/− mice. Here we show that the early burst of IL-4 expression observed in L. major-infected BALB/c mice is independent of IL-4Rα-mediated functions. Subsequently, we confirmed an impaired Th2 development in vitro. Unexpectedly, duringL. major infection, isolated CD4+IL-4Rα−/− T cells expressed high IL-4- but low gamma interferon (IFN-γ)-specific mRNA, comparable to Th2-polarized BALB/c CD4+ cells and in contrast to Th1-polarized C57BL/6 CD4+ cells. Since antigen-specific restimulated popliteal lymph node cells (PLN) of IL-4Rα−/− mice also responded with high IL-4 but low IFN-γ production, comparable to Th2-polarized cells from wild-type BALB/c mice and in contrast to Th1-polarized C57BL/6 cells, these results suggested an unimpaired Th2 polarization during an established infection with L. major. To further define the observed IL-4 receptor-independent Th2 cell phenotype, we determined an independent Th2 marker, the IL-12 receptor beta-2 (IL-12Rβ2)-specific transcript levels of CD4+ T cells. Confirming Th2 polarization in L. major-infected IL-4Rα−/− mice, comparable IL-12Rβ2 message levels between CD4+ T cells from infected IL-4Rα−/− mice and Th2 cells from BALB/c mice were found, whereas Th1-polarized C57BL/6 cells showed strikingly increased IL-12Rβ2 expression levels. These results indicate that signals mediated by the IL-4Rα are not necessary to induce and sustain an efficient IL-4 expression and Th2 polarization in L. major-infected BALB/c mice and suggest that IL-4Rα-independent mechanisms underlie the default Th2 development in L. major-infected BALB/c mice.

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Vaccination with DNA Encoding the Immunodominant LACK Parasite Antigen Confers Protective Immunity to Mice Infected with Leishmania major

Journal of Experimental Medicine ◽

10.1084/jem.186.7.1137 ◽

1997 ◽

Vol 186 (7) ◽

pp. 1137-1147 ◽

Cited By ~ 255

Author(s):

Sanjay Gurunathan ◽

David L. Sacks ◽

Daniel R. Brown ◽

Steven L. Reiner ◽

Hughes Charest ◽

...

Keyword(s):

T Cells ◽

Cd8 T Cells ◽

Protective Immunity ◽

Leishmania Major ◽

Protective Efficacy ◽

Dna Vaccination ◽

Attractive Alternative ◽

Dna Immunization ◽

Dna Encoding ◽

Ifn Γ

To determine whether DNA immunization could elicit protective immunity to Leishmania major in susceptible BALB/c mice, cDNA for the cloned Leishmania antigen LACK was inserted into a euykaryotic expression vector downstream to the cytomegalovirus promoter. Susceptible BALB/c mice were then vaccinated subcutaneously with LACK DNA and challenged with L. major promastigotes. We compared the protective efficacy of LACK DNA vaccination with that of recombinant LACK protein in the presence or absence of recombinant interleukin (rIL)-12 protein. Protection induced by LACK DNA was similar to that achieved by LACK protein and rIL-12, but superior to LACK protein without rIL-12. The immunity conferred by LACK DNA was durable insofar as mice challenged 5 wk after vaccination were still protected, and the infection was controlled for at least 20 wk after challenge. In addition, the ability of mice to control infection at sites distant to the site of vaccination suggests that systemic protection was achieved by LACK DNA vaccination. The control of disease progression and parasitic burden in mice vaccinated with LACK DNA was associated with enhancement of antigen-specific interferon-γ (IFN-γ) production. Moreover, both the enhancement of IFN-γ production and the protective immune response induced by LACK DNA vaccination was IL-12 dependent. Unexpectedly, depletion of CD8+ T cells at the time of vaccination or infection also abolished the protective response induced by LACK DNA vaccination, suggesting a role for CD8+ T cells in DNA vaccine induced protection to L. major. Thus, DNA immunization may offer an attractive alternative vaccination strategy against intracellular pathogens, as compared with conventional vaccination with antigens combined with adjuvants.

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The IL-6-deficient mouse exhibits impaired lymphocytic responses to a vaccine combining liveLeishmania majorand CpG oligodeoxynucleotides

Canadian Journal of Microbiology ◽

10.1139/w09-017 ◽

2009 ◽

Vol 55 (6) ◽

pp. 705-713 ◽

Cited By ~ 8

Author(s):

Wenhui Wu ◽

Luise Weigand ◽

Susana Mendez

Keyword(s):

T Cells ◽

Leishmania Major ◽

Wild Type ◽

Cpg Dna ◽

Cpg Oligodeoxynucleotides ◽

Inflammatory Stimuli ◽

Specific Expansion ◽

Ifn Γ ◽

Immune Defects ◽

Draining Lymph Nodes

We have previously reported that vaccination with CpG oligodeoxynucleotides delivered concomitantly with live Leishmania major (Lm/CpG) eliminates lesions associated with live vaccination in C57BL/6 mice. The absence of lesions is at least in part a result of the CpG DNA-mediated activation of dermal dendritic cells to produce cytokines such as interleukin (IL)-6. Wild-type C57BL/6 mice and IL-6−/− mice were immunized with the Lm/CpG vaccine and monitored for the development of lesions. IL-6−/− mice developed extensive, nonhealing lesions following live vaccination. The analysis of the inoculation site and draining lymph nodes of the IL-6−/− mice revealed a constitutive reduction in lymphocyte numbers, particularly CD4+ T cells. Live vaccination resulted in the specific expansion of CD4+Foxp3+ regulatory T cells in the knockout mice, and in a decrease of CD4+ IFN-γ -producing cells. These results indicate that IL-6−/− mice may have collateral immune defects that could influence the development of the natural immune response to pathogens, vaccines, or other inflammatory stimuli.

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Gamma Interferon Produced by Antigen-Specific CD4+ T Cells Regulates the Mucosal Immune Responses to Citrobacter rodentium Infection

Infection and Immunity ◽

10.1128/iai.01343-09 ◽

2010 ◽

Vol 78 (6) ◽

pp. 2653-2666 ◽

Cited By ~ 45

Author(s):

Hideyuki Shiomi ◽

Atsuhiro Masuda ◽

Shin Nishiumi ◽

Masayuki Nishida ◽

Tetsuya Takagawa ◽

...

Keyword(s):

T Cells ◽

Immune Responses ◽

Gamma Interferon ◽

Immune Defense ◽

Interleukin 4 ◽

Mucosal Inflammation ◽

Citrobacter Rodentium ◽

Macrophage Phagocytosis ◽

Ifn Γ ◽

Deficient Mice

ABSTRACT Citrobacter rodentium, a murine model pathogen for enteropathogenic Escherichia coli, colonizes the surface of intestinal epithelial cells and causes mucosal inflammation. This bacterium is an ideal model for investigating pathogen-host immune interactions in the gut. It is well known that gene transcripts for Th1 cytokines are highly induced in colonic tissue from mice infected with C. rodentium. However, it remains to be seen whether the Th1 or Th2 cytokines produced by antigen-specific CD4+ T cells provide effective regulation of the host immune defense against C. rodentium infection. To investigate the antigen-specific immune responses, C. rodentium expressing ovalbumin (OVA-C. rodentium), a model antigen, was generated and used to define antigen-specific responses under gamma interferon (IFN-γ)-deficient or interleukin-4 (IL-4)-deficient conditions in vivo. The activation of antigen-specific CD4+ T cells and macrophage phagocytosis were evaluated in the presence of IFN-γ or IL-4 in vitro. IFN-γ-deficient mice exhibited a loss of body weight and a higher bacterial concentration in feces during OVA-C. rodentium infection than C57BL/6 (wild type) or IL-4-deficient mice. This occurred through the decreased efficiency of macrophage phagocytosis and the activation of antigen-specific CD4+ T cells. Furthermore, a deficiency in antigen-specific CD4+ T-cell-expressed IFN-γ led to a higher susceptibility to mucosal and gut-derived systemic OVA-C. rodentium infection. These results show that the IFN-γ produced by antigen-specific CD4+ T cells plays an important role in the defense against C. rodentium.

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An Ex Vivo Study of T Lymphocytes Recovered from the Lungs of I/St Mice Infected with and Susceptible toMycobacterium tuberculosis

Infection and Immunity ◽

10.1128/iai.66.10.4981-4988.1998 ◽

1998 ◽

Vol 66 (10) ◽

pp. 4981-4988 ◽

Cited By ~ 33

Author(s):

Irina Lyadova ◽

Vladimir Yeremeev ◽

Konstantin Majorov ◽

Boris Nikonenko ◽

Sergei Khaidukov ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Ex Vivo ◽

Antimycobacterial Activity ◽

Enzymatic Digestion ◽

Interleukin 4 ◽

T Cell Clones ◽

Cell Clones ◽

Ifn Γ

ABSTRACT I/St mice, previously characterized as susceptible toMycobacterium tuberculosis H37Rv, were given 103 or 105 CFU intravenously. At two time points postinoculation, the cell suspensions that resulted from enzymatic digestion of lungs were enumerated and further characterized phenotypically and functionally. Regarding the T-cell populations recovered at 2 and 5 weeks postinfection, two main results were obtained: (i) the population of CD44− CD45RB+cells disappeared within 2 weeks postinfection, while the number of CD44+ CD45RB−/low cells slowly increased between weeks 2 and 5; (ii) when cocultured with irradiated syngeneic splenocytes, these lung T cells proliferated in the presence of H37Rv sonicate. Using H37Rv sonicate and irradiated syngeneic splenocytes to reactivate lung T cells, we selected five CD3+CD4+ CD8− T-cell clones. In addition to the H37Rv sonicate, the five clones react to both a short-term culture filtrate and an affinity-purified 15- to 18-kDa mycobacterial molecule as assessed by the proliferative assay. However, there was a clear difference between T-cell clones with respect to cytokine (gamma interferon [IFN-γ] and interleukin-4 [IL-4] and IL-10) profiles: besides one Th1-like (IFN-γ+ IL-4−) clone and one Th0-like (IFN-γ+ IL-4+IL-10+) clone, three clones produced predominantly IL-10, with only marginal or no IL-4 and IFN-γ responses. Inhibition of mycobacterial growth by macrophages in the presence of T cells was studied in a coculture in vitro system. It was found that the capacity to enhance antimycobacterial activity of macrophages fully correlated with INF-γ production by individual T-cell clones following genetically restricted recognition of infected macrophages. The possible functional significance of cytokine diversity among T-cell clones is discussed.

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