Screening and identification of H-2 d-restricted T cell epitopes in fusion and attachment glycoproteins of Nipah virus by ELISPOT / 中华微生物学和免疫学杂志

Objective:To screen and identify H-2 d-restricted T cell epitopes in fusion (F) and attachment (G) glycoproteins of Nipah virus (NiV) in mice. Methods:The complete peptides (single peptide contains 15 amino acids, and 10 amino acids were repeated in the front and back peptides) derived from F and G antigens were mixed into peptide libraries. BALB/c mice were immunized with DNA vaccines expressing NiV F and G proteins alone and in combination. The full sequence peptide libraries of F and G antigens were mixed into peptide pools by matrix design, and spleen cells of immunized mice were collected and analyzed by IFN-γ ELISPOT assay to detect the dominant H-2 d-restricted epitope peptides. Results:Twelve dominant H-2 d-restricted peptides were screened from the F protein-specific peptide library and the 56th peptide produced the strongest reaction. Four dominant peptides were screened from the G protein-specific peptide library and the 72nd peptide produced the strongest reaction. Conclusions:In this study, 12 F antigen-specific and 4 G antigen-specific H-2 d restricted dominant T cell epitopes of NiV were screened and identified by IFN-γ ELISPOT, which could provide reference for immunological analysis of NiV and vaccine research.

Comparison between Diagnostic Yield of Pleural Fluid ELISPOT and Thoracoscopic Guided Pleural Biopsy in Undiagnosed Pleural Effusion

Context: Despite recent advances in the available diagnostic modalities, diagnosis of pleural tuberculosis remains a challenge because of the low yield of conventional methods. Pleural biopsy is the gold standard for confirmation of diagnosis, which is invasive and cumbersome. The concentration of mycobacterial peptide-specific activated lymphocytes at the site of infection can be utilized as the basis for using IGRA (interferon-gamma release assays) based evaluation of undiagnosed exudative pleural effusions.  Aim: To evaluate the performance of IGRA (Enzyme-linked Immunospot (ELISPOT) in pleural fluid for the diagnosis of pleural tuberculosis in histopathologically confirmed cases. Settings and Design: A prospective observational study compared the utility of ELISPOT with thoracoscopy guided pleural biopsies for the diagnosis of tubercular pleural effusions. Methods and Material: Forty-two consecutive cases of undiagnosed pleural effusions were enrolled and subjected to thoracoscopy guided pleural biopsy. Thirteen patients were confirmed to have tuberculosis, 27 had malignancy, and 2 had normal pleura. A total of 1x103 pleural fluid mononuclear cells (PFMCs) were cultured in the presence of early secretory antigenic target-6 (ESAT-6) and culture filtrate protein-10 (CFP-10) for 24 hours. The individual spots were then counted using an automated analyzer ELISPOT reader system.  Results: The number of spots developed in the pleural fluid was significantly higher in tubercular pleural effusions as compared to non-tubercular effusions (CFP-10:154.76±14.61 vs 49.24±8.9; ESAT-6: 150.3±17.27 v/s 45.34±8.23, p<0.001). At a cut-off value of more than 67 spots taken as positive for tuberculosis, the sensitivity of the test was 100% (95% CI 75.29% to 100.00%), specificity was 96.5% (95 % CI 82.24% to 99.91%), positive predictive value was 92.86% (95 % CI 65.45% to 98.89%) and negative predictive value was 100%.  Conclusions: ELISPOT can be a useful non-invasive test for the evaluation of undiagnosed pleural effusions and making a diagnosis of pleural tuberculosis with confidence.

Detection and Analysis of Candida Albicans Enolase Antigen-Specific T Cells in Heathy Individuals by ELISPOT Assay / 现代检验医学杂志

Objective To observe the T cells immune response to Enolase (Eno),an immunodominant antigen of Candida albicans.Methods Determined the frequencies of positive spot-forming cells (SFCs) of Eno antigen-specific T cells secreting IFN-γ,IL-4 and IL-17A in the PBMCs of 25 healthy individuals by ELISPOT assay.Results After Eno stimulation,the SFCs of IFN-γ,IL-4 and IL 17A in 25 healthy persons were 14.00(8.50,39.00),0(0,0) and 2(1,4.50),respectively.Either the SFCs of IFN-γ or those of IL-17A were significantly higher than those of IL-4 (P＜0.05).The difference between SFCs of IFN-γ and those of IL-17A was also significant (P=0).The response rates of IFN-γ,IL-4 and IL-17A were 100％ (25/25),4.00％ (1/25) and 88.00％ (22/25),respectively.The difference between either IFN-γor IL 17A and IL-4 was significant (values all P＜0.05).Eno induced strong response (SCFs≥20) for IFN-γ in 10 healthy individuals (40.00％,10/25),but failed to induce strong response for IL-17A and IL-4 in all the volunteers.Major healthy individuals (84.00％,21/25)showed both Th1 and Th17 cells response against Eno,12.00％ (3/25) showing Th1 cells response in isolation,and none showed Th2 or Th17 cells response individually.Conclusion Eno of Candida albicans could induce immunodominant responses of Th1 and Th17 cells,which was considered to provide protection to IC.Eno might be a potential protective vaccine against IC.

The Detailed Kinetics of Cytomegalovirus-specific T cell Responses after Hematopoietic Stem Cell Transplantation: 1 Year Follow-up Data

The detailed kinetics of the cytomegalovirus (CMV)-specific T cell response in hematopoietic stem cell transplant (HCT) recipients have not yet been fully assessed. We evaluated these kinetics of CMV-specific T cell response and factors associated with high CMV-specific T cell responses 1 year after HCT. In HCT recipients, CMV pp65 and IE1-specific ELISPOT assay were performed before HCT (D0), and at 30 (D30), 90 (D90), 180 (D180), and 360 (D360) days after HCT. Of the 51 HCT recipients with donor-positive (D+)/recipient-positive (R+) serology, 26 (51%) developed CMV infections after HCT. The patterns of post-transplantation reconstitution for CMV-specific T cell response were classified into 4 types: 1) an initial decrease at D30 followed by gradual T cell reconstitution without CMV infection (35%), 2) an initial decrease at D30 followed by gradual T cell reconstitution preceded by CMV infection (35%), 3) failure of gradual or constant T cell reconstitution (26%), and 4) no significant T cell reconstitution (4%). There was no significant difference between ELISPOT counts of D360 and those of D0. High CMV-specific T cell responses at D360 were not associated with high CMV-specific T cell response at D0, CMV infection, ganciclovir therapy, graft versus host disease (GVHD), and immunosuppressant use. In conclusion, there are 4 distinct patterns of reconstitution of the CMV-specific T cell response after HCT. In addition, reconstituted donor-origin CMV-specific T cell responses appeared to be constant until day 360 after HCT, regardless of the level of the pre-transplant CMV-specific T cell response, CMV infection, and immunosuppressant use.

Application of T-SPOT.TB in the Early Diagnosis of Tuberculosis / 现代检验医学杂志

Objective This study aims to explore the application value of tuberculosis T lymphocytes enzyme-linked immune SPOT test (T-SPOT.TB) on early diagnosis of tuberculosis.Methods The TB infection in 189 inpatients suspected tuberculosis in pneumology department of Shaanxi Provincial People's Hospital was detected with T-SPOT.TB,fluorescence RQPCR,tuberculosis (TB-Ab)protein chip and PPD methods.Results The sensitivity of four methods was 91.54％ (119/130),73.85％(96/130),63.08％(82/130) and 57.69％ (75/130) respectively and the specificity of those was 89.83％ (53/59),86.44％(51/59),67.79％(40/59) and 66.10％(39/59),respectively.The sensitivity of T-SPOT.TB method was statistically higher than those of other three tests,respectively (P＜0.05).The specificity of T-SPOT.TB was significantly higher than those of TB-AB and PPD (P＜0.05),but there was no statistical difference between RQ-PCR and T-SPOT.TB (P＞0.05).The positive predictive values of T-SPOT.TB,fluorescent quantitative PCR,TB-Ab and PPD assays were 95.2％ (119/1250),92.3％ (96/104),81.2％ (82/101) and 78.9％ (75/95) respectively while the negative predictive values of those were 82.8％ (53/64),60％ (51/85),45.5％ (40/88) and 41.5％ (39/94),respectively.The false-positive rates (misdiagnosis rate) of four assays were 10.2％ (6/59),13.6％ (8/59),32.2％ (19/59) and 33.9％ (20/59) respectively and the false-negative rates (rates of missed diagnosis) of those were 8.5％ (11/130),26.2％ (34/130),36.9％ (48/130)and 42.3 ％ (55/130),respectively.The negative likelihood ratios of T SPOT.TB,fluorescent quantitative PCR,TB-Ab and PPD assays were 0.11,0.16,0.48 and 0.51 respectively,meanwhile the positive likelihood ratios of T-SPOT.TB,fluorescent quantitative PCR,TB-Ab andPPD assays were 9.0,5.4,2.0 and 1.7,respectively.What' s more,the diagnostic accordance rates of the four assays were 91.0％ (172 189),77.8％ (147 189).64.6％ (122/189) and 60.3％ (114/189),respectively.Conclusion T-SPOT.TB test is a more sensitive and specific method and of great significance to the early diagnosis of TB,which has more clinical value in different stages of tuberculosis diagnosis.

Can dida colonizait on associated with the humoral immune anamnestci respon se oft he dominant antigen in the early stage of invasive Candidosis / 医学研究生学报

Objective Rapid elevation of the IgG antibody against Candida Enolase ( Eno ) has been observed in patients with invasive candidosis in an early stage .The present study was to confirm the association of Candida colonization with humoral im-mune anamnestic response of the dominant antigen . Methods Twenty-four mice were randomized into group 1 treated by oral Candi-da colonization plus intraperitoneal infection ( immunocompetent , n=8) , 2 treated with immunosuppressant in addition to the treatment of group 1 ( immunocompromised , n=8) , 3 treated by oral Candida colonization only ( immunocompetent , n=4) and 4 treated by in-traperitoneal injection only( immunocompetent, n=4).The number of Eno-specific memory B-cells in the spleen and the levels of IgG , IgM and IgA antibodies were determined in the peripheral blood of the immunocompetent and immunocompromised invasive candidiasis mice . Results At 7 days after invasive infection , there were significantly more Eno-specific memory B-cells in the mice of groups1 ( 47.25 ± 13.81) and 2 (43.14±15.95) than in groups 3 (8.00±3.74) and 4(8.50±2.38) (P0.05).Eno-IgG antibodies were detected in the serum of the mice of the first two groups in the early stage of invasive infection and positively corre -lated with antigen-specific memory B-cells (r=0.737,P <00.1 ). Conclusion Rapid elevation of the Eno-IgG antibody level in the early stage of invasive infection after Candida colonization may be attributed to the rapid proliferation of humoral immune memory cells.

Detection of Candida albicans fructose bisphosphate aldolase antigen-specific T cells in healthy individuals by ELISPOT assay / 医学研究生学报

Objective Invasive candidiasis is associated with a significant mortality clinically.The purpose of this study was to observe the T cells immune response to fructose bisphosphate aldolase (Fba), an immunodominant antigen of Candida albicans, and determine whether the antigen has the possibility of priming cellular immune protection in invasive candiasis.Methods Using ELISPOT assay, we determined the frequencies of positive spot-forming cells (SFCs) of Fba antigen-specific T cells secreting IFN-γ, IL-4 and IL-17A in the peripheral blood mononuclear cells (PBMCs) of 26 healthy individuals.Results After Fba stimulation, the frequencies of positive SFCs of IFN-γ, IL-4 and IL-17A in the 26 healthy subjects were 23 (9.75, 42.50), 0 (0, 0.25) and 1.5 (0.75, 8.25), respectively, with statistically significant differences among the three (P<0.01).The response rates of IFN-γ (100% [26/26]) and IL-17A (76.92% [20/26]) were significantly higher than that of IL-4 (15.38% [4/26]) (P<0.01).Fba-induced strong response (SCFs ≥20) for IFN-γ was observed in 57.69% (15/26) of the healthy individuals, that for IL-17A in only 1, while that for IL-4 in none.Responses of both Th1 and Th17 cells to Fba were found in 65.38% (17/26) of the subjects, that of Th1 cells in 19.23% (5/26), but that of Th2 cells in none.Conclusion Fba of Candida albicans can induce immunodominant responses of Th1 and Th17 cells and is a potential vaccine against invasive candiasis.

Mycobacterium tuberculosis epitope-specific interferon-g production in healthy Brazilians reactive and non-reactive to tuberculin skin test

The interferon (IFN)-γ response to peptides can be a useful diagnostic marker of Mycobacterium tuberculosis (MTB) latent infection. We identified promiscuous and potentially protective CD4+ T-cell epitopes from the most conserved regions of MTB antigenic proteins by scanning the MTB antigenic proteins GroEL2, phosphate-binding protein 1 precursor and 19 kDa antigen with the TEPITOPE algorithm. Seven peptide sequences predicted to bind to multiple human leukocyte antigen (HLA)-DR molecules were synthesised and tested with IFN-γ enzyme-linked immunospot (ELISPOT) assays using peripheral blood mononuclear cells (PBMCs) from 16 Mantoux tuberculin skin test (TST)-positive and 16 TST-negative healthy donors. Eighty-eight percent of TST-positive donors responded to at least one of the peptides, compared to 25% of TST-negative donors. Each individual peptide induced IFN-γ production by PBMCs from at least 31% of the TST-positive donors. The magnitude of the response against all peptides was 182 ± 230 x 106 IFN-γ spot forming cells (SFC) among TST-positive donors and 36 ± 62 x 106 SFC among TST-negative donors (p = 0.007). The response to GroEL2 (463-477) was only observed in the TST-positive group. This combination of novel MTB CD4 T-cell epitopes should be tested in a larger cohort of individuals with latent tuberculosis (TB) to evaluate its potential to diagnose latent TB and it may be included in ELISPOT-based IFN-γ assays to identify individuals with this condition.

Detection of Aspergillus fumigatus thioredoxin reductase GliT antigen-specific T cells by ELISPOT assay in healthy individuals and result evaluation / 医学研究生学报

Objective The purpose of this study was to evaluate the protective potential of the Aspergillus fumigatus thiore -doxin reductase GliT ( TR) antigen by establishing and optimizing ELISPOT assay for TR antigen-specific T cells ( TR/AST) secreting IFN-γand IL-4 in peripheral blood mononuclear cells ( PBMCs ) and explore the role of TR/AST in invasive aspergillosis ( IA ) . Methods We optimized the reaction conditions of ELISPOT by preliminary checkerboard titration and determined the frequencies of positive spot-forming cells ( SFCs) specifically secreting IFN-γand IL-4 in the PBMCs of 20 healthy individuals with TR as specific stimulant and with PHA and PMA as positive controls ,. Results Checkerboard titration demonstrated the best result of ELISPOT with the TR antigen at the final concentration of 10μg/well and PBMCs at 3 ×105/well.The median frequency of IFN-γSFCs was sig-nificantly higher (15 [3.5, 59.5]) than that of IL-4 SFCs (0 [0, 0]) (P20/3 ×105 PBMCs), accounting for 45%, but failed to induce IL-4 response in 19 of the healthy individuals . Conclusion The Aspergillus fumigatus TR antigen could induce an immunodominant Th1 response , and therefore might be a potential protective antigen .

Antigen-specific helper T cells in patients with pemphigus vulgaris / 中华皮肤科杂志

Objective To study the changes of antigen-specific T helper type 1 (Th1) cells and Th2 cells in patients with pemphigus vulgaris (PV) at different stages,so as to better understand the roles of autoreactive T cells in PV.Methods The DG3 (96-112) peptide was synthesized.Twenty-four patients with PV and 10 health checkup examinees were included in this study.Peripheral blood mononuclear cells (PBMCs) were obtained from the health checkup examinees and all the patients before treatment and seven patients about one month after treatment,and stimulated with the DG3 peptide of 10 mg/L for different durations.Then,enzyme-linked immunospot (ELISPOT) assay was performed to count the number of DG3-specific IFN-γ+ Th1 cells,IL-4+ Th2 cells and memory B cells.One-way analysis of variance (ANOVA) and t test were done to compare the number of cells between different groups,and Pearson correlation coefficient was used to evaluate the correlation among Th cells,memory B cells and anti-desmoglein 3 (Dsg3) antibody titers.Results In these patients,the male to female ratio was 1.67 ∶ 1,and the average age was (56.59 ± 14.66) years.Compared with the health check-up examinees,the patients with PV showed a higher absolute number of DG3-specific IFN-γ+ Th1 cells (420.18 ± 350.29 vs.145.12 ± 86.56,t =3.25,P ＜ 0.05),but a similar absolute number of specific IL-4+ Th2 cells (366.76 ± 192.44 vs.335.88 ± 164.96,P＞ 0.05) per 5 × 105 PBMCs.The percentage of DG3-specific IL-4+ Th2 cells in Th2 cells was 37.03％ ± 23.44％,and the percentage of IFN-γ+ Th1 cells was 23.62％ ± 16.77％ in peripheral blood of patients with PV.The number of DG3-specific IL-4+ Th2 cells per 5 × 105 PBMCs significantly decreased from 452.82 ± 199.29 before treatment to 241.68 ± 160.60 after treatment in seven patients (t =2.48,P ＜ 0.05).There was no significant correlation between specific Th cells,memory B cells and anti-Dsg3 antibody titers (all P ＞ 0.05).Conclusions The peptide DG3 (96-112) has pathogenic epitopes which could be recognized by specific Th cells of patients with PV.Both antigen-specific IFN-γ+ Th1 cells and IL-4+ Th2 cells play certain roles in the pathogenesis of pemphigns vulgaris,and IL-4+ Th2 cells appear to be more important.

Indeterminate T-SPOT.TB Test Results in Patients with Suspected Extrapulmonary Tuberculosis in Routine Clinical Practice / 감염과화학요법

BACKGROUND: The two interferon-gamma release assays such as QuantiFERON-TB Gold / In-Tube (QFT-TB) and T-SPOT.TB-are useful tools for the rapid diagnosis of tuberculosis (TB) but can yield indeterminate test results (ITRs). While some studies have identified risk factors for ITRs in the QFT-TB test, there have been few such studies for the T-SPOT.TB test. The aim of this study was to investigate the risk factors associated with ITRs in the T-SPOT.TB test. MATERIALS AND METHODS: From April 2008 to August 2010, all patients with suspected extrapulmonary tuberculosis (E-TB) were enrolled in a tertiary hospital in Korea. ITR was defined as 10 spots in the negative control well. RESULTS: Out of a total of 368 patients, 32 (8.7%, 95% CI, 6.0% to 11.7%) had ITRs in their T-SPOT.TB tests. The ITRs were due to a low mitogen response in 13 (40.6%) patients and to a high nil response in the other 19 (59.4%) patients. Statistical analysis revealed that old age, underlying diseases, immunosuppressive treatment, lymphopenia, and clinical manifestations of E-TB were not significantly associated with ITRs. CONCLUSIONS: Indeterminate results in the T-SPOT.TB test are not affected by age, underlying disease, immunosuppressive treatment, lymphopenia, or clinical manifestations of E-TB, which are known risk factors for indeterminate results in the QFT-TB test.

Analysis of influence of HLA-B broad specific Bw4 motif on HCV specific T cell response / 中华微生物学和免疫学杂志

Objective To study the influence of Bw4 broad specific motif on hepatitis C virus (HCV) specific T cell response.Methods The 86 patients with HCV infection were enrolled in this study,who had history of non-standard paid blood donation.The sequence specific primer SSP-PCR and specific primer Amplification Refractory Mutation system was used to analyze HLA type.The T cell response,using PBMCs stimulated by HCV nonstructural protein NS3,NS4 and NS5 was tested by ELISPOT assay.Results There were 29 (33.7％) cases with homozygosity Bw4/4,38 cases (44.2％) with heterozygosity Bw4/6 and 19(22.1％) cases with homozygosity Bw6/6 in 86 patients with HCV infection.HCV viral loads in Bw4/4group,Bw4/6 group and Bw6/6 group were (3.98±0.32) Log (copy/ml),(5.22± 0.29) Log (copy/ml),(5.04±0.38) Log(copy/ml),respectively and there was a significant difference in HCV load among three groups(P=0.0153).The 24 cases with HCV infection were test HCV specific T cell response divided homozygosity Bw4/4 group and non-homozygosity Bw4/4 group.The HCV specific T cell response frequency in homozygosity Bw4/4 group and non-homozygosity Bw4/4 group was 50％ (5/10) and 14.28％ (2/14,respectively.The HCV specific T cell response magnitude in homozygosity Bw4/4 group and non-homozygosity Bw4/4 group was 70 SFU/106 PBMC (0-2020 SFU/106 PBMC)and 0 SFU/106 PBMC (0-200 SFU/106 PBMC).The response magnitude and frequency in homozygosity Bw4/4 group was significantly higher than that of non-homozygosity Bw4/4 group,P value was 0.0450 and 0.069,respectively.In homozygosity Bw4/4 group NS5 induced T cell response was dominant.The NS5 specific T cell response frequency in Bw4/4 group and non-Bw4/4 group was 50％ and 7.14％,respectively,and the difference was nearly significant(P=0.050).Conclusion The HCV-infected blood donors with homozygosity for HLA-Bw4 alleles is associated with a significant lower HCV virus load and stronger HCV specific T cell response,compared with non-homozygosity Bw4/4 group.

Comparison of the early immune responses in mice vaccinated by different kinds of hepatitis B surface antigen / 中华微生物学和免疫学杂志

ObjectiveTo evaluate the early cellular immune responses to three kinds of hepatitis B surface antigen (HBsAg) in the immunized mice.MethodsAt day 4,the levels of IFN-γand IL-2 secreted by CD4+ and CD8+T cells which selected from splenic mononuclear cells (MNC) of the vaccinated mice were detected by enzyme-linked immunospot methods (ELISPOT) after stimulation in vitro with HBsAg MHC class Ⅰ peptide S28-39 of HBsAg or recombinant hepatitis B surface antigen(rHBsAg).ResultsAfter selected by MACs,the purity of CD3+/CD4+ and CD3+/CD8+T cell was more than 90％.The positive rate of IFN-γsecreted by CD4+T cells induced by HBsAg derived from Hansenula polymorpha(rHP) was higher than that of HBsAg derived from CHO cell (rCHO).Levels of IFN-γ secreted by CD8+T cells and IL-2 secreted by CD4+T cells induced by rHP antigen were significantly higher than those of rCHO( P＜0.05 ).Meanwhile,levels of IFN-γsecreted by CD4+T cells and CD8+T cells induced by rHP were also significantly higher than those of plasma HBsAg(pHB) (P＜0.05).ConclusionAt day 4,the cellular immune responses induced by HBsAg could be detected.But the immune responses induced by the three kinds of HBsAg are different in levels.According to early cellular immune response intensity,the rHP HBsAg are superior to the rCHO and pHB,in accordance with the high protection rate interrupting the mother-infant transmission immunized by rHP vaccine in clinical trial.It provides scientific basis for necessity of timely birth dose of HB vaccine and kind of HB vaccine for high risk newborn infants vaccinated.

Clinical Usefulness of T-SPOT.TB Test for the Diagnosis of Tuberculosis / 대한진단검사의학회지

BACKGROUND: Tuberculosis-specific ELISPOT assay (T-SPOT.TB, Oxford Immunotec, UK) is a test that detects interferon-gamma producing T-cells after stimulating patient's lymphocytes with two kinds of tuberculosis-specific antigens (ESAT-6 and CFP-10). We evaluated clinical usefulness of T-SPOT.TB test in Korean adults with intermediate burden of tuberculosis and high rate of BCG vaccination at birth. METHODS: T-SPOT.TB test was performed in 79 patients and 64 healthy volunteers and these patients and volunteers were classified into four groups: group 1, patients with active tuberculosis (n=30); group 2, patients with not-active tuberculosis (n=27); group 3, patients without tuberculosis (n=24); group 4, healthy volunteers without tuberculosis history (n=62). Positive rates and average spot counts of T-SPOT.TB test were obtained among these groups. RESULTS: Positive rates of group 1 (96.4%) and group 2 (92.3%) were higher than those of group 3 (31.6%) and group 4 (27.4%) (P<0.0001). The sensitivity deduced from group 1 and specificity deduced from group 4 of T-SPOT.TB test were 96.4% and 72.6%, respectively. The average spot counts of group 1 and 2 were higher than those of group 3 and 4 (P<0.001). There was a tendency of increasing positive rate with increasing age. Overall agreement between T-SPOT.TB test and tuberculin skin test was 63.8% (kappa=0.29). CONCLUSIONS: T-SPOT.TB test would be a very useful screening and supplementary test for diagnosis of tuberculosis due to its high sensitivity. However, positive results of T-SPOT.TB should be cautiously interpreted because of high positivity in treated tuberculosis patients and healthy volunteers in Korea.

O desafio da tuberculose na faixa etária pediátrica frente a novas técnicas diagnósticas: [revisão] / The challenge of pediatric tuberculosis in face of new diagnostic techniques: [review]

OBJETIVOS: Apresentar uma revisão atualizada sobre os novos métodos para o diagnóstico da tuberculose baseados na produção in vitro de interferon-gama (IFN-γ) por células T dos pacientes sob investigação, comparando-os com a tradicional prova tuberculínica. FONTES DOS DADOS: Revisão de literatura utilizando os bancos de dados MEDLINE e LILACS (2000-2008) utilizando as palavras-chave tuberculose, interferon-gama, quantiFERON, ELISPOT e T-SPOT.TB. SÍNTESE DOS DADOS: Esses novos testes mostraram-se, de um modo geral, tão ou mais sensíveis e específicos que a prova tuberculínica, tanto em adultos como em crianças e imunossuprimidos, para o diagnóstico da infecção latente e da doença ativa, apresentando vantagens como a menor interferência da vacinação prévia pelo BCG, menor influência de estados anérgicos e melhor acurácia em crianças menores. Nos Estados Unidos, já estão sendo utilizados em substituição à prova tuberculínica, e apesar dos custos ainda elevados, a Organização Mundial de Saúde vai priorizar a sua viabilidade econômica. CONCLUSÕES: Sempre levando em conta a importância da história clínica e epidemiológica, os novos testes baseados na produção de IFN-γ apresentam resultados promissores e deverão ser considerados na investigação de tuberculose em qualquer paciente, mas especialmente nos grupos de risco, como as crianças e os imunossuprimidos.

OBJECTIVES: To present an updated review concerning new assays for diagnosing tuberculosis based on in vitro interferon-gamma production by host T cells, and compare them with tuberculin skin test. SOURCES: A literature review was carried out based on Medline and LILACS databases (2000-2008) searching for the following keywords: tuberculosis, interferon-gamma, quantiFERON, ELISPOT and T-SPOT.TB. SUMMARY OF THE FINDINGS: These new assays proved to have, in general, equal or superior sensitivity and specificity than the tuberculin skin test not only in adults but also in children and immunosuppressed patients for the diagnosis of both latent tuberculosis infection or active disease, with some advantages such as less cross-reactivity as a result of previous BCG vaccination, less influence of anergy and better accuracy in small children. In the United States, these assays have been used instead of the tuberculin skin test and, although still very expensive, the World Health Organization will be making its economic viability a priority. CONCLUSIONS: Always having in mind the importance of clinical and epidemiological histories, these new assays based on interferon-gamma release present promising results and should be considered in tuberculosis investigation procedures for all patients, however with a special concern in the risk groups (i.e., children and immunosuppressed patients).

Pre-transplant donor reactive IFN-γ producing cell and TGF-β producing cell frequencies and their clinical significance / 中华泌尿外科杂志

n a more rational basis.

Pol-specific T lymphocyte responses in Chinese HIV-1 recombinant subtype B/C infectors at different stages of diseases / 中华微生物学和免疫学杂志

Objective To analyze the character of Pol-specific T lymphocyte responses and identify immunodominant region recognized in Chinese HIV-1 recombinant subtype B/C infectors at different stages of diseases. Methods Eleven Chinese HIV-1 recombinant subtype B/C infectors infected in 18 months, 25 which infected time more than 3 years and 10 HIV-1-seronegative healthy individuals were enrolled. HIV-1-specific T lymphocyte responses were analyzed by an IFN-γ ELISPOT assay against 249 overlapping peptides spanning HIV-1 Pol protein in the present study. Results Pol-specific T lymphocyte responses of IFN-γsecretion were identified in 8 (72.73%) out of 11 infectors infected in 18 months, the specific T lymphocytes are mainly targe-ted at six peptides which amino acid position from Pol 481 to 631 in reverse transcriptase region: Pol5581, Pol5582, Pol5587, Pol5609, Pol5610 and Pol5615. There was a negative correlation between the breadth of re-sponse and peripheral CD4+ T cell count (P=0.0212, r=-0.762) ; Responses were identified in 15 (60%) out of 25 chronic infectors, the specific T lymphocytes are mainly targeted at four peptides which amino acid po-sition from Pol 241 to 295: Pol5521, Pol5525, Pol5526, Pol5531 and another peptide: Pol5638 which amino acid position from Pol 708 to 722 in reverse transcriptase region. There was a positive correlation between the magnitude of Pol-specific IFN-γ secretion T lymphocyte responses and plasma viremia (P = 0.006 95 , r = 0.660) . None of the seronegative healthy individuals gave the positive responses. Conclusion Chinese HIV-1 recombinant subtype B/C infectors at different stages of diseases mainly recognized different re-gions of Pol.

In vitro induction and detection of human B cells producing HLA antibodies / 中华微生物学和免疫学杂志

Objective To induce and detect human B cells producing HLA antibodies in vitro and by an ELISPOT assay. Methods Human peripheral blood mononuclear cells (PBMC) from 7 healthy vol-unteers were isolated by density gradient centrifugation, and cultured with the stimulation of PWM alone or PWM + SAC for 5 d. The lg levels in culture supernatants and the number of Ig producing B cells were de-termined by ELISA and ELISPOT assay, respectively. The optimal stimulation protocol for PBMC to produce optimal Ig in vitro was anticipated to be obtained. Using the optimal pre-cuhure and ELISPOT conditions, PBMC from 9 alloimmunized subjects were analyzed for the presence of B cells secreting HLA antibodies. Results There was a tendency towards more viable cells following the activation with PWM and SAC vs PWM alone in a 5-day culture (P =0. 052). The IgG levels in the supernatants were found to be comparable for the two culture conditions whereas the lgM levels were increased ( P = 0.03 ) in the presence of the com-bination of PWM and SAC. In 6 subjects a specific signal was obtained with our ELISPOT assay. The presence of HLA antibodies in the respective pre-cuhure supernatants supported the specificity. Conclusion The activation of PBMC with the combination of PWM and SAC, and the application of HLA-specifie ELIS-POT assay can succeed in the induction and detection of human B cells producing HLA antibodies.

Measurement of peripheral blood mononuclear cells producing IFN-Gamma in patients with tuberculosis

The type of immune response induced by tuberculosis (Th1 or Th2) and its correlation with the clinical outcome is unclear. We studied 13 patients with active tuberculosis (TBC). The peripheral blood mononuclear cells producing IFN-gamma (PBMC-IG) were measured by enzyme-linked immunospot (ELISPOT) technique. The control group had ten healthy individuals vaccinated against tuberculosis. We collected blood samples of each patient in two moments: a) in the hospital admission without treatment (TBC1); b) after seven to 20 days of treatment (TBC2). The comparison of the spots forming units of PBMC-IG between TBC group and controls showed that there was a significant difference between TBC1 and control group (p < 0.001) and between TBC2 and control group (p < 0.005), but there was no difference between TBC1 and TBC2 (p > 0.05). A positive correlation was found between PBMC-IG and hemoglobin value, as well as between PBMC-IG and weight loss. There was no correlation between PBMC-IG and other variables [age, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP)]. We conclude that tuberculosis activates Th1 immune response due to increase of PBMC producing IFN-gamma. There was no difference between the first sample (TBC1) and the second sample (TBC2) of PBMC-IG. This result can have occurred due to treatment influence, or can indicate that the immune response reachs a plateau. The positive correlation among PBMC-IG and both hemoglobin level and weight loss indicates that may exist a link between patient's clinical status and the immune response intensity.

Comparison of the Immunogenicities of HIV-1 Mutants Based on Structural Modification of env / 中国病毒学·英文版

Eleven env mutants were designed and generated by site-directed mutagenesis of the regions around Nab epitopes and deletions of variable regions in env.The immunogenicities of the generated mutants were evaluated using single-cycle infection neutralization assays with two pseudoviruses and IFN-γELISPOT.Overall,five mutants(dWt,M2,M5-2,M5-1 and dM7)induced highed neutralization activities for both pseudoviruses than plasmid Wt,while only two of the mutants(dWt and M5-2)showed significant differences(P<0.05).Two mutants(M2 and dM2)induced more Env-specific T cells than plasmid Wt.Statistically however,significance was only reached for mutant M2.Thus,properly modified HIV-1 Env may have the potential to induce potent cellular and humoral immune responses.