Natural killer (NK) cells are cytotoxic innate lymphoid cells that are emerging as a cellular imm... more Natural killer (NK) cells are cytotoxic innate lymphoid cells that are emerging as a cellular immunotherapy for various malignancies. NK cells are particularly dependent on interleukin (IL)-15 for their survival, proliferation, and cytotoxic function. NK cells differentiate into memory-like cells with enhanced effector function after a brief activation with IL-12, IL-15, and IL-18. N-803 is an IL-15 superagonist composed of an IL-15 mutant (IL-15N72D) bound to the sushi domain of IL-15Rα fused to the Fc region of IgG1, which results in physiological trans-presentation of IL-15. Here, we describe the creation of a novel triple-cytokine fusion molecule, 18/12/TxM, using the N-803 scaffold fused to IL-18 via the IL-15N72D domain and linked to a heteromeric single-chain IL-12 p70 by the sushi domain of the IL-15Rα. This molecule displays trispecific cytokine activity through its binding and signaling through the individual cytokine receptors. Compared with activation with the individual cytokines, 18/12/TxM induces similar short-term activation and memory-like differentiation of NK cells on both the transcriptional and protein level and identical in vitro and in vivo anti-tumor activity. Thus, N-803 can be modified as a functional scaffold for the creation of cytokine immunotherapies with multiple receptor specificities to activate NK cells for adoptive cellular therapy.
Tuberculosis is a leading cause of death due to single infectious agent accounting 1.4 million de... more Tuberculosis is a leading cause of death due to single infectious agent accounting 1.4 million deaths each year. The only licensed vaccine, BCG, is not effective due to variable efficacy. ABSTRACT Tuberculosis (TB) is one of the leading causes of death due to a single infectious agent. The development of a TB vaccine that induces durable and effective immunity to Mycobacterium tuberculosis (Mtb) infection is urgently needed. Early and superior Mtb control can be induced in M. bovis Bacillus Calmette-Guérin (BCG)-vaccinated hosts when the innate immune response is targeted to generate effective vaccine-induced immunity. In the present study, we show that innate activation of DCs is critical for mucosal localization of clonally activated vaccine-induced CD4+ T cells in the lung and superior early Mtb control. In addition, our study reveals that Th1/Th17 cytokine axis play an important role in superior vaccine-induced immunity. Our studies also show that activation of the nuclear facto...
BackgroundNatural killer (NK) cells are a nascent cellular immunotherapy for hematologic malignan... more BackgroundNatural killer (NK) cells are a nascent cellular immunotherapy for hematologic malignancies. Target recognition of NK cell-resistant cancers remains a substantial barrier to broad application of NK cell therapy. One solution are bispecific engagers that trigger NK cells via an NK activating receptor when simultaneously engaging a tumor-specific antigen.MethodsHere, we investigated single NK cell responses stimulated by the tetravalent bispecific innate cell engager (ICE®) AFM13 that binds CD30 on leukemia/lymphoma targets and CD16A on several types of NK cells.ResultsMultidimensional mass cytometry revealed heterogeneity within AFM13-directed conventional (c)NK cell responses, as well as consistent polyfunctional activation of mature terminally differentiated NK cells across donors. The source of NK cells also impacted the AFM13 response, with cNK cells from healthy donors exhibiting superior responses to those from Hodgkin lymphoma patients. IL-12, IL-15, and IL-18-induce...
Natural killer (NK) cells are a promising cellular immunotherapy for cancer. Cytokine-induced mem... more Natural killer (NK) cells are a promising cellular immunotherapy for cancer. Cytokine-induced memory-like (ML) NK cells differentiate after activation with interleukin-12 (IL-12), IL-15, and IL-18, exhibit potent antitumor responses, and safely induce complete remissions in patients with leukemia. However, many cancers are not fully recognized via NK cell receptors. Chimeric antigen receptors (CARs) have been used to enhance tumor-specific recognition by effector lymphocytes. We hypothesized that ML differentiation and CAR engineering would result in complementary improvements in NK cell responses against NK-resistant cancers. To test this idea, peripheral blood ML NK cells were modified to express an anti-CD19 CAR (19-CAR-ML), which displayed significantly increased interferon γ production, degranulation, and specific killing against NK-resistant lymphoma lines and primary targets compared with nonspecific control CAR-ML NK cells or conventional CAR NK cells. The 19-CAR and ML resp...
In the version of this Letter originally published, in Fig. 2d, in the third graph, the label for... more In the version of this Letter originally published, in Fig. 2d, in the third graph, the label for the y axis was incorrect as 'TNF-α (pg ml)'; it should have read 'IL-1β (pg ml)'. This has now been corrected.
Tuberculosis is a significant global health threat, with one-third of the world's population ... more Tuberculosis is a significant global health threat, with one-third of the world's population infected with its causative agent Mycobacterium tuberculosis (Mtb). The emergence of multidrug-resistant (MDR) Mtb that is resistant to the frontline anti-tubercular drugs rifampicin and isoniazid forces treatment with toxic second-line drugs. Currently, ~4% of new and ~21% of previously treated tuberculosis cases are either rifampicin-drug-resistant or MDR Mtb infections. The specific molecular host-pathogen interactions mediating the rapid worldwide spread of MDR Mtb strains remain poorly understood. W-Beijing Mtb strains are highly prevalent throughout the world and associated with increased drug resistance. In the early 1990s, closely related MDR W-Beijing Mtb strains (W strains) were identified in large institutional outbreaks in New York City and caused high mortality rates. The production of interleukin-1β (IL-1β) by macrophages coincides with the shift towards aerobic glycolysis,...
The establishment of a protective T-cell response against mycobacterial infections involves diffe... more The establishment of a protective T-cell response against mycobacterial infections involves different co-stimulatory molecules and their respective ligands. Among these molecules the Tumor Necrosis Factor Receptor Super-family (TNFRSF) and the Tumor Necrosis Factor Super-family (TNFSF) are known to be important members. This review analyzes the evidence that CD30 and CD153 (CD30L), members of the TNFRSF and TNSF, play key roles in the T cell-dependent anti-mycobacterial immune response. Mice deficient in either CD30 or CD153, or treated with antibodies blocking the effects or CD30 and CD153, and infected with M.avium or M.bovis BCG exhibit higher bacterial burden, abnormal inflammatory responses with decreased Th1 responses, this is evidenced by the reduced number of IFN-γ-producing cells. Recent evidence also showed that CD30(+) CD153(+) Tγδ cells participate in the early stages of M.bovis BCG infection by producing IL-17A. In humans, stimulation of T-cells with mycobacterial antigens induces CD30 expression mainly by CD4(+) cells; CD30(+) cells have been demonstrated in tissues of patients with tuberculosis (TB) and in positive tuberculin skin test reactions. In addition, the levels of soluble CD30 are increased in serum and BAL of TB patients and these levels seems to correlate with the severity of the disease. These findings suggest that CD30/CD153 interactions during the anti-mycobacterial immune response are important for the establishment and maintenance of a protective response. Further studies would be required to determine whether these molecules may be good clinical biomarkers or potential targets for immune manipulation.
Patients with pulmonary tuberculosis (PTB) frequently have reduced IFN-γ production in response t... more Patients with pulmonary tuberculosis (PTB) frequently have reduced IFN-γ production in response to mycobacterial antigens, compared to individuals with latent Mycobacterium tuberculosis infection (LTBi). However, it is not clear whether this reduced responsiveness is restricted to a particular T cell subset. Herein, PBMCs from 26 PTB patients, 30 household contacts (HHCs) of PTB, and 30 tuberculin positive (TST+) healthy subjects not recently exposed to PTB, were stained with CFSE and stimulated non-specific (PPD) for 120 h, and specific (CFP-10/ESAT-6) and latency (HSpX) mycobacterial antigens for 144 h and the percentage of CD4(+) and CD8(+)IFN-γ(+) T cells responding determined by flow cytometry, in addition to their memory phenotype by the CD45RO and CD27 expression. PTB had decreased frequency of both CD4(+) and CD8(+) precursor cells, as well as decreased number of CD4(+)IFN-γ(+) cells in response to all antigens, whereas CD8(+)IFN-γ(+) cells were decreased in response to PPD and ESAT-6, but not to CFP-10 and HSpX. HHCs exhibited the highest precursor frequencies and IFN-γ responses, irrespective of the antigen employed. The CD4(+)/CD8(+) cell ratios showed that in response to PPD CD4(+) precursor and IFN-γ-producer cells are more frequent than their CD8(+) counterparts, and that PTB have a decreased CD4(+)IFN-γ(+)/CD8(+)IFN-γ(+) ratio in response to PPD, CFP-10, and ESAT-6. CD4(+)IFN-γ(+) and CD8(+)IFN-γ(+) cells exhibited a central memory phenotype (CD45RO(+)CD27(+)), irrespective of the group of subjects and the antigen used for stimulation. In conclusion, PTB patients had a decreased percentage of CD4(+) and CD8(+) precursor cells and CD4(+)IFN-γ(+). HHCs exhibited the highest frequency of CD4(+) and CD8(+) precursors and CD4(+)IFN-γ(+)-producing cells.
Tuberculosis (TB) is one of the most important infectious diseases around the world. Several stud... more Tuberculosis (TB) is one of the most important infectious diseases around the world. Several studies have focused on the identification of correlates of protection against TB. Most of them have concentrated on the study of IFN-γ due to its robust association with protection against TB. However, given the complexity of the immune response elicited after Mtb infection, other cytokines should also be considered. In the present study, we evaluated Th1 and Th17 responses and their association with the protection or development of active disease. Therefore, non infected individuals (nonTBi), latently infected individuals (LTBi) and patients with active TB (ATB) were studied. The evaluation of the number of cytokine producing cells by ELISPOT showed a higher number of IFN-γ-producing cells in ATB patients, but no differences were found regarding the number of IL-17 producing cells among studied groups. The evaluation of IFN-γ, IL-2, TNF-α and IL-17 producing CD4+ and CD8+ T cells at 1 day and 6 days of stimulation with mycobacterial antigens suggests the presence of functional signatures associated with latency or active TB. The results presented herein suggest the possible use of the evaluation of Th1-type cytokines, such as IFN-γ and/or TNF-α, as a correlate of protection against TB; however, these results need to be validated for other groups.
ABSTRACTPhenotypic and functional alterations inMycobacterium tuberculosisT cell subsets have bee... more ABSTRACTPhenotypic and functional alterations inMycobacterium tuberculosisT cell subsets have been reported in patients with active tuberculosis. A better understanding of these alterations will increase the knowledge about immunopathogenesis and also may contribute to the development of new diagnostics and prophylactic strategies. Here, theex vivophenotype of CD4+and CD8+T cells and the frequency and phenotype of gamma interferon (IFN-γ)- and interleukin 17 (IL-17)-producing cells elicited in short-term and long-term cultures following CFP-10 and purified protein derivative (PPD) stimulation were determined in noninfected persons (non-TBi), latently infected persons (LTBi), and patients with active tuberculosis (ATB). Phenotypic characterization of T cells was done based on the expression of CD45RO and CD27. Results show that ATB had a reduced frequency of circulating CD4+CD45RO+CD27+T cells and an increased frequency of CD4+CD45RO−CD27+T cells. ATB also had a higher frequency of c...
Regulatory T cells (Tregs) play an essential role in immune homeostasis. In infectious diseases T... more Regulatory T cells (Tregs) play an essential role in immune homeostasis. In infectious diseases Tregs may inhibit protective responses facilitating pathogen multiplication and dissemination, but they may also limit the inflammatory response diminishing tissue damage. Although there is experimental and clinical evidence that Tregs are induced during Mycobacterium tuberculosis infection, their role in the immunopathogenesis of tuberculosis is still not completely understood. In this study, the phenotype, frequency and activity of circulating Tregs in active and latent tuberculosis were evaluated. Phenotypic analysis showed that Tregs were CD4(+)CD25(high)FOXP3(+)CD45RO(+)CD127(-). High levels of circulating Tregs were found in patients with active pulmonary tuberculosis, compared to individuals with latent infection. Treg activity was evaluated by ELISPOT by determining the effect of CD25(+) cell depletion on the frequency of IFN-gamma and IL-17 producing cells after in vitro stimulation with ESAT-6, CFP-10 and PPD. Treg depletion increased the frequency of IFN-gamma producing cells, without affecting the frequency of IL-17 producing cells, in both active and latent tuberculosis, irrespective of the antigen used. Neutralization of IL-10 did not have any effect on the frequency of IFN-gamma and IL-17 producing cells. Altogether, these results suggest that during active tuberculosis Tregs inhibit protective Th1 responses, but not the proinflammatory Th17 responses, facilitating mycobacterial replication and tissue damage.
The mechanisms of mononuclear phagocyte death have been associated with the permissiveness and re... more The mechanisms of mononuclear phagocyte death have been associated with the permissiveness and resistance to mycobacterial replication, but it remains unknown whether or not they help predict the risk of developing TB. To describe the factors associated with the induction of monocyte mitochondrial and membrane damage in response to PPD as well as determine if this type of damage might predict the susceptibility of developing active tuberculosis in a cohort of household contacts (HHCs) from Medellin, Colombia from 2005 to 2008. The prospective cohort study contains 2060 HHCs patients with pulmonary tuberculosis who were meticulously followed for two years. A survey of the socio-demographic, clinical, epidemiological factors and blood samples were collected. Mononuclear cell cultures were stimulated with or without PPD and the type of monocyte death was determined by the flow of cytometry, an indicator was also used for its analysis. Logistic regression was adjusted by the Generalized...
Objectives: Household contacts (HHCs) of pulmonary tuberculosis patients are at high risk of Myco... more Objectives: Household contacts (HHCs) of pulmonary tuberculosis patients are at high risk of Mycobacterium tuberculosis infection and early disease development. Identification of individuals at risk of tuberculosis disease is a desirable goal for tuberculosis control. Interferon-gamma release assays (IGRAs) using specific M. tuberculosis antigens provide an alternative to tuberculin skin testing (TST) for infection detection. Additionally, the levels of IFNc produced in response to these antigens may have prognostic value. We estimated the prevalence of M. tuberculosis infection by IGRA and TST in HHCs and their source population (SP), and assessed whether IFNc levels in HHCs correlate with tuberculosis development.
Objectives: Household contacts (HHCs) of pulmonary tuberculosis patients are at high risk of Myco... more Objectives: Household contacts (HHCs) of pulmonary tuberculosis patients are at high risk of Mycobacterium tuberculosis infection and early disease development. Identification of individuals at risk of tuberculosis disease is a desirable goal for tuberculosis control. Interferon-gamma release assays (IGRAs) using specific M. tuberculosis antigens provide an alternative to tuberculin skin testing (TST) for infection detection. Additionally, the levels of IFNc produced in response to these antigens may have prognostic value. We estimated the prevalence of M. tuberculosis infection by IGRA and TST in HHCs and their source population (SP), and assessed whether IFNc levels in HHCs correlate with tuberculosis development.
Natural killer (NK) cells are cytotoxic innate lymphoid cells that are emerging as a cellular imm... more Natural killer (NK) cells are cytotoxic innate lymphoid cells that are emerging as a cellular immunotherapy for various malignancies. NK cells are particularly dependent on interleukin (IL)-15 for their survival, proliferation, and cytotoxic function. NK cells differentiate into memory-like cells with enhanced effector function after a brief activation with IL-12, IL-15, and IL-18. N-803 is an IL-15 superagonist composed of an IL-15 mutant (IL-15N72D) bound to the sushi domain of IL-15Rα fused to the Fc region of IgG1, which results in physiological trans-presentation of IL-15. Here, we describe the creation of a novel triple-cytokine fusion molecule, 18/12/TxM, using the N-803 scaffold fused to IL-18 via the IL-15N72D domain and linked to a heteromeric single-chain IL-12 p70 by the sushi domain of the IL-15Rα. This molecule displays trispecific cytokine activity through its binding and signaling through the individual cytokine receptors. Compared with activation with the individual cytokines, 18/12/TxM induces similar short-term activation and memory-like differentiation of NK cells on both the transcriptional and protein level and identical in vitro and in vivo anti-tumor activity. Thus, N-803 can be modified as a functional scaffold for the creation of cytokine immunotherapies with multiple receptor specificities to activate NK cells for adoptive cellular therapy.
Tuberculosis is a leading cause of death due to single infectious agent accounting 1.4 million de... more Tuberculosis is a leading cause of death due to single infectious agent accounting 1.4 million deaths each year. The only licensed vaccine, BCG, is not effective due to variable efficacy. ABSTRACT Tuberculosis (TB) is one of the leading causes of death due to a single infectious agent. The development of a TB vaccine that induces durable and effective immunity to Mycobacterium tuberculosis (Mtb) infection is urgently needed. Early and superior Mtb control can be induced in M. bovis Bacillus Calmette-Guérin (BCG)-vaccinated hosts when the innate immune response is targeted to generate effective vaccine-induced immunity. In the present study, we show that innate activation of DCs is critical for mucosal localization of clonally activated vaccine-induced CD4+ T cells in the lung and superior early Mtb control. In addition, our study reveals that Th1/Th17 cytokine axis play an important role in superior vaccine-induced immunity. Our studies also show that activation of the nuclear facto...
BackgroundNatural killer (NK) cells are a nascent cellular immunotherapy for hematologic malignan... more BackgroundNatural killer (NK) cells are a nascent cellular immunotherapy for hematologic malignancies. Target recognition of NK cell-resistant cancers remains a substantial barrier to broad application of NK cell therapy. One solution are bispecific engagers that trigger NK cells via an NK activating receptor when simultaneously engaging a tumor-specific antigen.MethodsHere, we investigated single NK cell responses stimulated by the tetravalent bispecific innate cell engager (ICE®) AFM13 that binds CD30 on leukemia/lymphoma targets and CD16A on several types of NK cells.ResultsMultidimensional mass cytometry revealed heterogeneity within AFM13-directed conventional (c)NK cell responses, as well as consistent polyfunctional activation of mature terminally differentiated NK cells across donors. The source of NK cells also impacted the AFM13 response, with cNK cells from healthy donors exhibiting superior responses to those from Hodgkin lymphoma patients. IL-12, IL-15, and IL-18-induce...
Natural killer (NK) cells are a promising cellular immunotherapy for cancer. Cytokine-induced mem... more Natural killer (NK) cells are a promising cellular immunotherapy for cancer. Cytokine-induced memory-like (ML) NK cells differentiate after activation with interleukin-12 (IL-12), IL-15, and IL-18, exhibit potent antitumor responses, and safely induce complete remissions in patients with leukemia. However, many cancers are not fully recognized via NK cell receptors. Chimeric antigen receptors (CARs) have been used to enhance tumor-specific recognition by effector lymphocytes. We hypothesized that ML differentiation and CAR engineering would result in complementary improvements in NK cell responses against NK-resistant cancers. To test this idea, peripheral blood ML NK cells were modified to express an anti-CD19 CAR (19-CAR-ML), which displayed significantly increased interferon γ production, degranulation, and specific killing against NK-resistant lymphoma lines and primary targets compared with nonspecific control CAR-ML NK cells or conventional CAR NK cells. The 19-CAR and ML resp...
In the version of this Letter originally published, in Fig. 2d, in the third graph, the label for... more In the version of this Letter originally published, in Fig. 2d, in the third graph, the label for the y axis was incorrect as 'TNF-α (pg ml)'; it should have read 'IL-1β (pg ml)'. This has now been corrected.
Tuberculosis is a significant global health threat, with one-third of the world's population ... more Tuberculosis is a significant global health threat, with one-third of the world's population infected with its causative agent Mycobacterium tuberculosis (Mtb). The emergence of multidrug-resistant (MDR) Mtb that is resistant to the frontline anti-tubercular drugs rifampicin and isoniazid forces treatment with toxic second-line drugs. Currently, ~4% of new and ~21% of previously treated tuberculosis cases are either rifampicin-drug-resistant or MDR Mtb infections. The specific molecular host-pathogen interactions mediating the rapid worldwide spread of MDR Mtb strains remain poorly understood. W-Beijing Mtb strains are highly prevalent throughout the world and associated with increased drug resistance. In the early 1990s, closely related MDR W-Beijing Mtb strains (W strains) were identified in large institutional outbreaks in New York City and caused high mortality rates. The production of interleukin-1β (IL-1β) by macrophages coincides with the shift towards aerobic glycolysis,...
The establishment of a protective T-cell response against mycobacterial infections involves diffe... more The establishment of a protective T-cell response against mycobacterial infections involves different co-stimulatory molecules and their respective ligands. Among these molecules the Tumor Necrosis Factor Receptor Super-family (TNFRSF) and the Tumor Necrosis Factor Super-family (TNFSF) are known to be important members. This review analyzes the evidence that CD30 and CD153 (CD30L), members of the TNFRSF and TNSF, play key roles in the T cell-dependent anti-mycobacterial immune response. Mice deficient in either CD30 or CD153, or treated with antibodies blocking the effects or CD30 and CD153, and infected with M.avium or M.bovis BCG exhibit higher bacterial burden, abnormal inflammatory responses with decreased Th1 responses, this is evidenced by the reduced number of IFN-γ-producing cells. Recent evidence also showed that CD30(+) CD153(+) Tγδ cells participate in the early stages of M.bovis BCG infection by producing IL-17A. In humans, stimulation of T-cells with mycobacterial antigens induces CD30 expression mainly by CD4(+) cells; CD30(+) cells have been demonstrated in tissues of patients with tuberculosis (TB) and in positive tuberculin skin test reactions. In addition, the levels of soluble CD30 are increased in serum and BAL of TB patients and these levels seems to correlate with the severity of the disease. These findings suggest that CD30/CD153 interactions during the anti-mycobacterial immune response are important for the establishment and maintenance of a protective response. Further studies would be required to determine whether these molecules may be good clinical biomarkers or potential targets for immune manipulation.
Patients with pulmonary tuberculosis (PTB) frequently have reduced IFN-γ production in response t... more Patients with pulmonary tuberculosis (PTB) frequently have reduced IFN-γ production in response to mycobacterial antigens, compared to individuals with latent Mycobacterium tuberculosis infection (LTBi). However, it is not clear whether this reduced responsiveness is restricted to a particular T cell subset. Herein, PBMCs from 26 PTB patients, 30 household contacts (HHCs) of PTB, and 30 tuberculin positive (TST+) healthy subjects not recently exposed to PTB, were stained with CFSE and stimulated non-specific (PPD) for 120 h, and specific (CFP-10/ESAT-6) and latency (HSpX) mycobacterial antigens for 144 h and the percentage of CD4(+) and CD8(+)IFN-γ(+) T cells responding determined by flow cytometry, in addition to their memory phenotype by the CD45RO and CD27 expression. PTB had decreased frequency of both CD4(+) and CD8(+) precursor cells, as well as decreased number of CD4(+)IFN-γ(+) cells in response to all antigens, whereas CD8(+)IFN-γ(+) cells were decreased in response to PPD and ESAT-6, but not to CFP-10 and HSpX. HHCs exhibited the highest precursor frequencies and IFN-γ responses, irrespective of the antigen employed. The CD4(+)/CD8(+) cell ratios showed that in response to PPD CD4(+) precursor and IFN-γ-producer cells are more frequent than their CD8(+) counterparts, and that PTB have a decreased CD4(+)IFN-γ(+)/CD8(+)IFN-γ(+) ratio in response to PPD, CFP-10, and ESAT-6. CD4(+)IFN-γ(+) and CD8(+)IFN-γ(+) cells exhibited a central memory phenotype (CD45RO(+)CD27(+)), irrespective of the group of subjects and the antigen used for stimulation. In conclusion, PTB patients had a decreased percentage of CD4(+) and CD8(+) precursor cells and CD4(+)IFN-γ(+). HHCs exhibited the highest frequency of CD4(+) and CD8(+) precursors and CD4(+)IFN-γ(+)-producing cells.
Tuberculosis (TB) is one of the most important infectious diseases around the world. Several stud... more Tuberculosis (TB) is one of the most important infectious diseases around the world. Several studies have focused on the identification of correlates of protection against TB. Most of them have concentrated on the study of IFN-γ due to its robust association with protection against TB. However, given the complexity of the immune response elicited after Mtb infection, other cytokines should also be considered. In the present study, we evaluated Th1 and Th17 responses and their association with the protection or development of active disease. Therefore, non infected individuals (nonTBi), latently infected individuals (LTBi) and patients with active TB (ATB) were studied. The evaluation of the number of cytokine producing cells by ELISPOT showed a higher number of IFN-γ-producing cells in ATB patients, but no differences were found regarding the number of IL-17 producing cells among studied groups. The evaluation of IFN-γ, IL-2, TNF-α and IL-17 producing CD4+ and CD8+ T cells at 1 day and 6 days of stimulation with mycobacterial antigens suggests the presence of functional signatures associated with latency or active TB. The results presented herein suggest the possible use of the evaluation of Th1-type cytokines, such as IFN-γ and/or TNF-α, as a correlate of protection against TB; however, these results need to be validated for other groups.
ABSTRACTPhenotypic and functional alterations inMycobacterium tuberculosisT cell subsets have bee... more ABSTRACTPhenotypic and functional alterations inMycobacterium tuberculosisT cell subsets have been reported in patients with active tuberculosis. A better understanding of these alterations will increase the knowledge about immunopathogenesis and also may contribute to the development of new diagnostics and prophylactic strategies. Here, theex vivophenotype of CD4+and CD8+T cells and the frequency and phenotype of gamma interferon (IFN-γ)- and interleukin 17 (IL-17)-producing cells elicited in short-term and long-term cultures following CFP-10 and purified protein derivative (PPD) stimulation were determined in noninfected persons (non-TBi), latently infected persons (LTBi), and patients with active tuberculosis (ATB). Phenotypic characterization of T cells was done based on the expression of CD45RO and CD27. Results show that ATB had a reduced frequency of circulating CD4+CD45RO+CD27+T cells and an increased frequency of CD4+CD45RO−CD27+T cells. ATB also had a higher frequency of c...
Regulatory T cells (Tregs) play an essential role in immune homeostasis. In infectious diseases T... more Regulatory T cells (Tregs) play an essential role in immune homeostasis. In infectious diseases Tregs may inhibit protective responses facilitating pathogen multiplication and dissemination, but they may also limit the inflammatory response diminishing tissue damage. Although there is experimental and clinical evidence that Tregs are induced during Mycobacterium tuberculosis infection, their role in the immunopathogenesis of tuberculosis is still not completely understood. In this study, the phenotype, frequency and activity of circulating Tregs in active and latent tuberculosis were evaluated. Phenotypic analysis showed that Tregs were CD4(+)CD25(high)FOXP3(+)CD45RO(+)CD127(-). High levels of circulating Tregs were found in patients with active pulmonary tuberculosis, compared to individuals with latent infection. Treg activity was evaluated by ELISPOT by determining the effect of CD25(+) cell depletion on the frequency of IFN-gamma and IL-17 producing cells after in vitro stimulation with ESAT-6, CFP-10 and PPD. Treg depletion increased the frequency of IFN-gamma producing cells, without affecting the frequency of IL-17 producing cells, in both active and latent tuberculosis, irrespective of the antigen used. Neutralization of IL-10 did not have any effect on the frequency of IFN-gamma and IL-17 producing cells. Altogether, these results suggest that during active tuberculosis Tregs inhibit protective Th1 responses, but not the proinflammatory Th17 responses, facilitating mycobacterial replication and tissue damage.
The mechanisms of mononuclear phagocyte death have been associated with the permissiveness and re... more The mechanisms of mononuclear phagocyte death have been associated with the permissiveness and resistance to mycobacterial replication, but it remains unknown whether or not they help predict the risk of developing TB. To describe the factors associated with the induction of monocyte mitochondrial and membrane damage in response to PPD as well as determine if this type of damage might predict the susceptibility of developing active tuberculosis in a cohort of household contacts (HHCs) from Medellin, Colombia from 2005 to 2008. The prospective cohort study contains 2060 HHCs patients with pulmonary tuberculosis who were meticulously followed for two years. A survey of the socio-demographic, clinical, epidemiological factors and blood samples were collected. Mononuclear cell cultures were stimulated with or without PPD and the type of monocyte death was determined by the flow of cytometry, an indicator was also used for its analysis. Logistic regression was adjusted by the Generalized...
Objectives: Household contacts (HHCs) of pulmonary tuberculosis patients are at high risk of Myco... more Objectives: Household contacts (HHCs) of pulmonary tuberculosis patients are at high risk of Mycobacterium tuberculosis infection and early disease development. Identification of individuals at risk of tuberculosis disease is a desirable goal for tuberculosis control. Interferon-gamma release assays (IGRAs) using specific M. tuberculosis antigens provide an alternative to tuberculin skin testing (TST) for infection detection. Additionally, the levels of IFNc produced in response to these antigens may have prognostic value. We estimated the prevalence of M. tuberculosis infection by IGRA and TST in HHCs and their source population (SP), and assessed whether IFNc levels in HHCs correlate with tuberculosis development.
Objectives: Household contacts (HHCs) of pulmonary tuberculosis patients are at high risk of Myco... more Objectives: Household contacts (HHCs) of pulmonary tuberculosis patients are at high risk of Mycobacterium tuberculosis infection and early disease development. Identification of individuals at risk of tuberculosis disease is a desirable goal for tuberculosis control. Interferon-gamma release assays (IGRAs) using specific M. tuberculosis antigens provide an alternative to tuberculin skin testing (TST) for infection detection. Additionally, the levels of IFNc produced in response to these antigens may have prognostic value. We estimated the prevalence of M. tuberculosis infection by IGRA and TST in HHCs and their source population (SP), and assessed whether IFNc levels in HHCs correlate with tuberculosis development.
Uploads
Papers by Nancy Marin