Depressed interleukin-12 production by peripheral blood mononuclear cells after in vitro stimulation with the 30-kDa antigen in recurrent pulmonary tuberculosis patients

Cytokine production and mRNA expression in pulmonary tuberculosis patients and their household contacts of younger age group (15-25years)

Household contacts of tuberculosis patients are at high risk of infection and development of active disease. In this study we evaluated the cytokine production and mRNA expression of IFN-γ, TNF-α, IL-10&IL-6 stimulated with r32kDa M. bovis BCGAg in active pulmonary tuberculosis patients (APTB), household contacts (HHC) and healthy controls (HC). The results showed the stimulated levels of IFN-γ and TNF-α were low while IL-10 levels were high in APTB and HHC compared to HC. IL-6 has not shown any significant difference. The mRNA expression of TNF- α was 8 fold high in HCs compared to APTB and HHC. The IL-6 expression was 2.2 fold &1 fold less in APTB and HHC compared to HCs. Multinomial logistic regression analysis indicated that the stimulated levels of IFN-γ & IL-6 and sex significantly predicted the HHC group from HCs at p<0.05.In conclusion further follow up studies with r32kd antigen might help to identify the high risk individuals.

Effective expansion of forkhead box P3⁺ regulatory T cells via early secreted antigenic target 6 and antigen 85 complex B from Mycobacterium tuberculosis

The expansion of CD4+ CD25+ forkhead box (FOX)P3+ regulatory T (Treg) cells has been observed in patients with Mycobacterium (M.) tuberculosis; however, the mechanism of expansion remains to be elucidated. The aim of the present study was to examine the role of the early secreted antigenic target 6(ESAT‑6) and antigen 85 complex B (Ag85B) from M. tuberculosis on Treg cell expansion. To investigate the sensitivity of peripheral blood cultures to the M. tuberculosis ESAT‑6 and Ag85B antigens, the proportion of circulating CD4+ CD25+ FOXP3+ Treg cells was determined using flow cytometry and the levels of FOXP3 mRNA were determined using reverse transcription quantitative polymerase chain reaction. The mRNA levels of FOXP3 and the proportion of circulating CD4+ CD25+ FOXP3+ Treg cells were increased in multiplicitous drug‑resistant tuberculosis patients compared with those in healthy controls and patients with latent tuberculosis (TB) infection (LTBI) (P<0.001). The mycobacterial antigens ESAT‑6 and Ag85B increased the expansion of the CD4+ CD25+ FOXP3+ Treg cells and the mRNA levels of FOXP3 in healthy controls and LTBI patients compared with the effect of Bacillus Calmette‑Guerin (P<0.05). Additionally, the mRNA levels of FOXP3 were elevated in the LTBI patients following stimulations with the mycobacterial antigens (P=0.012). Therefore, the M. tuberculosis antigens ESAT‑6 and Ag85B induced CD4+ CD25+ FOXP3+ Treg‑cell expansion, particularly in patients with LTBI. These findings indicated that CD4+ CD25+ FOXP3+ Treg cells may have a primary role in the failure of the host immune system to eradicate M. tuberculosis.

The 30-kDa and 38-kDa antigens from Mycobacterium tuberculosis induce partial maturation of human dendritic cells shifting CD4(+) T cell responses towards IL-4 production

BACKGROUND

Mycobacterium tuberculosis (Mtb) infections are still a major cause of death among all infectious diseases. Although 99% of individuals infected with Mtb develop a CD4(+) Th1 and CD8(+) T cell mediated immunity as measured by tuberculin skin test, this results only in partial protection and Mtb vaccines are not effective. Deviation of immune responses by pathogens towards a Th2 profile is a common mechanism of immune evasion, typically leading to the persistence of the microbes.

RESULTS

Here we tested the stimulatory capacity of selective Mtb antigens on human monocyte-derived dendritic cell (DC) maturation and cytokine production. DC maturation markers CD80, CD86 and CD83 were readily upregulated by H37Ra- and H37Rv-associated antigens, the 30-kDa (from Ag85 B complex) and 38-KDa Mtb antigens only partially induced these markers. All Mtb antigens induced variable levels of IL-6 and low levels of IL-10, there was no release of IL-12p70 detectable. Substantial IL-12p40 production was restricted to LPS or H37Ra and H37Rv preparations. Although the proliferation levels of primary T cell responses were comparable using all the differentially stimulated DC, the 30-kDa and 38-kDa antigens showed a bias towards IL-4 secretion of polarized CD4(+) T cells after secondary stimulation as compared to H37Ra and H37Rv preparations.

CONCLUSION

Together our data indicate that 30-kDa and 38-kDa Mtb antigens induced only partial DC maturation shifting immune responses towards a Th2 profile.

Decreased expression of T-cell costimulatory molecule CD28 on CD4 and CD8 T cells of mexican patients with pulmonary tuberculosis

Patients with tuberculosis frequently develop anergy, a state of T-cell hyporesponsiveness in which defective T-cell costimulation could be a factor. To know if the expression of T-cell costimulatory molecules was altered in tuberculosis, we analyzed the peripheral blood T-cell phenotype of 23 Mexican patients with pulmonary tuberculosis. There was severe CD4 (P < .001) and CD8 (P < .01) lymphopenia and upregulation of costimulatory molecule CD30 on CD4 and CD8 T cells (P < .05); this increase was higher in relapsing tuberculosis. The main finding was severe downregulation of the major costimulatory molecule CD28 on both CD8 and CD4 T cells (P < .001). Depletion of the CD4/CD28 subset, a hitherto undescribed finding, is relevant because CD4 T cells constitute the main arm of the cell-mediated antimycobacterial immune response.

In vitro levels of cytokines in response to purified protein derivative (PPD) antigen in a population with high prevalence of pulmonary tuberculosis

The control of mycobacterial infection by the host depends on cell-mediated immunity (CMI), involving activated macrophages, T cells, and type 1 cytokines (Th1). Here we evaluated the capacity of antigen-induced proliferation by peripheral blood mononuclear cells (PBMCs) and the production of proinflammatory tumor necrosis factor-alpha (TNF-α) and interleukin 12 (IL-12p40). The Th1 cytokine interferon-gamma (IFN-γ) and Th2 cytokines interleukin 4 (IL-4) and interleukin 5 (IL-5) in 62 pulmonary tuberculosis (TB) patients (40 Warao indigenous patients [WP] and 22 Creole non-indigenous patients [CP]) and 24 healthy controls (12 Warao indigenous controls [WC] and 12 Creole non-indigenous controls [CC]) at 24 and 48 hours in response to purified protein derivative (PPD) from Mycobacterium tuberculosis. The overall results revealed that testing of CP and CC' PBMCs for TNF-α, IFN-γ, and IL-12p40 production was higher compared with WP and WC' PBMCs after stimulating for 24 and 48 hours (p < 0.0001), within the WP group, the lower productions of IL-12p40 and IFN-γ significantly correlated (r(2) = 0.91, p < 0.01). Although in general there was interindividual variability in the observed responses of Th2 cytokines, especially with IL-4, there was a trend to produce higher PPD-induced IL-5 by WP' PBMCs compared with WC' PBMCs and CP' PBMCs at 24 and 48 hours, respectively. High IL-5 production correlated inversely with low IFN-γ production (r(2) = -0.97, p < 0.002). In conclusion, our results suggest that PPD-induced responses observed in patients from both populations can be divided into two groups: one group that activates Creole' PBMCs to preferentially secrete TNF-α, IL-12p40 and IFN-γ and another group that activates preferential secretion of IL-5 in Warao' PBMCs.

Expression and regulation of the CC-chemokine ligand 20 during human tuberculosis

CC-chemokine ligand 20 (CCL20), a unique chemokine ligand of CC-chemokine receptor 6 (CCR6), play roles in various pathologic conditions. However, the characteristic expression profiles of CCL20 during human tuberculosis (TB) have been largely unknown. The present study analyzed the production and regulatory mechanisms of CCL20 in peripheral blood mononuclear cells (PBMC) and monocyte-derived macrophages (MDM) from active pulmonary TB patients and healthy controls (HC). The 30-kDa antigen (Ag) of Mycobacterium tuberculosis actively induced the production of CCL20 by human PBMC and MDM. A comparative analysis revealed that the expression of CCL20 protein was prominently up-regulated in PBMC, MDM, bronchoalveolar lavage fluids (not in sera) from TB patients compared with the corresponding cells or body fluids from HC. Blockade of either tumour necrosis factor-alpha or interferon-gamma, but not interleukin-10, significantly attenuated the CCL20 production. In addition, recombinant CCL20 induced CCR6 expression by CD45RO+ T lymphocytes in a dose-dependent manner. Furthermore, the expression of CCR6 was significantly increased in CD45RO+ T lymphocytes from TB patients, as compared with those from HC. Pharmacological inhibition studies showed that the 30-kDa Ag-induced CCL20 mRNA expression involves mitogen-activated protein kinases (MAPK; extracellular signal-regulated kinase 1/2 and p38)- and NF-kappaB-dependent signalling. Collectively, the present study demonstrated that TB patients show the up-regulated expression of CCL20, which is modulated by proinflammatory cytokines, and through MAPK/NF-kappaB-mediated transcriptional mechanisms. The findings suggest important implications of potential roles of CCL20-CCR6 in immunopathogenesis of TB.

Polymorphisms of interleukin-10 and tumour necrosis factor-? genes are associated with newly diagnosed and recurrent pulmonary tuberculosis

BACKGROUND AND OBJECTIVES

The genetic determinants for developing TB or having recurrent TB are unknown. The present study investigated the relationship between susceptibility to tuberculosis and human tumour necrosis factor-alpha (TNF-alpha) and interleukin-10 genes (IL-10).

METHODS

A case-control study was conducted using two groups of cases--newly diagnosed TB (N-TB) and recurrent TB (R-TB)--and a control group.

RESULTS

One hundred and seventeen healthy controls, 80 newly diagnosed TB patients and 65 patients with recurrent TB were enrolled. There was no significant difference in the TNF-alpha-308 G/A genotype between the TB patient groups and the controls. The IL-10 -1082A alleles were markedly over-represented among the TB patient groups compared with the control subjects, however, there was no significant difference in the IL-10 genotype frequency between the N-TB and R-TB patient groups.

CONCLUSION

The -1082A allele of the IL-10 gene may be important in determining susceptibility to TB, however, the -308 allele of the TNF-alpha gene does not affect differential TB susceptibility.

Changes in serum cytokine levels in active tuberculosis with treatment

It has been reported that IFN-γ, TNF-α, and IL-12 stimulate, and that IL-10, TGF-β, and IL-4 suppress the protective immune response against tuberculosis. We aim to evaluate changes in the serum levels of pro and antiinflammatory cytokines in active pulmonary tuberculosis (APTB) and the possible effects of treatment on these changes. Serum IL-12p40, IL-4, IL-10, TNF-α, IFN-γ, and TGF-β1 levels were determined in 20 APTB cases (group 1) before and 2, 4, and 6 months after therapy. The same parameters were also determined in 9 inactive pulmonary tuberculosis (IPTB) cases (group 2) and 9 healthy controls (HC, group 3). Before treatment, the mean serum IFN-γ, TNF-α, and IL-10 levels in group 1 were statistically higher than those in group 2 (P = .001, P = .024, P = .016, resp) or group 3 (P = .003, P = .002, P = .011, resp). The levels in group 1 decreased significantly after treatment (P = .001 for IFN-γ, P = .004 for TNF-α, P = .000 for IL-10). The serum levels of IL-12p40 were significantly higher in group 1 than in group 3 (P = .012) and decreased insignificantly after treatment. There was no difference in serum IL-4 and TGF-β1 levels among the groups (P > .05). Because the serum IL-12p40, IL-10, TNF-α, and IFN-γ levels were high in APTB, we believe that these cytokines have important roles in the immune response to Mycobacterium tuberculosis (M tuberculosis). These parameters could be used in follow-up as indicators of the success of APTB therapy.