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

Modeling of MT. P495, an mRNA-based vaccine against the phosphate-binding protein PstS1 of Mycobacterium tuberculosis

Tuberculosis (TB) is a contagious disease that predominantly affects the lungs, but can also spread to other organs via the bloodstream. TB affects about one-fourth population of the world. With age, the effectiveness of Bacillus Calmette-Guérin (BCG), the only authorized TB vaccine, decreases. In the quest for a prophylactic and immunotherapeutic vaccine, in this study, a hypothetical mRNA vaccine is delineated, named MT. P495, implementing in silico and immunoinformatics approaches to evaluate key aspects and immunogenic epitopes across the PstS1, a highly conserved periplasmic protein of Mycobacterium tuberculosis (Mtb). PstS1 elicited the potential to generate 99.9% population coverage worldwide. The presence of T- and B-cell epitopes across the PstS1 protein were validated using several computational prediction tools. Molecular docking and dynamics simulation confirmed stable epitope-allele interaction. Immune cell response to the antigen clearance rate was verified by the in silico analysis of immune simulation. Codon optimization confirmed the efficient translation of the mRNA in the host cell. With Toll-like receptors, the vaccine exhibited stable and strong interactions. Findings suggest that the MT. P495 vaccine probably will elicit specific immune responses against Mtb. This mRNA vaccine model is a ready source for further wet-lab validation to confirm the efficacy of this proposed vaccine candidate.

Persistent expression of activation markers on Mycobacterium tuberculosis-specific CD4 T cells in smear negative TB patients

Background

T cell activation (HLA-DR, CD-38), proliferation (KI-67), and functional (IFN-γ, TNF-α) markers have recently been shown to be useful in predicting and monitoring anti-TB responses in smear positive TB, but previous research did not characterize the activation and proliferation profiles after therapy of smear negative TB.

Methodology

In this study, we used polychromatic flow cytometry to assess selected PPD-specific T cell markers using fresh PBMC of smear negative and positive pulmonary tuberculosis (PTB) patients, recruited from health facilities in Addis Ababa.

Result

Levels of activation (HLA-DR, CD38) and proliferation (Ki-67) among total unstimulated CD4 T cells decreased significantly after therapy, particularly at month 6. Similarly, levels of PPD-specific T cell activation markers (HLA-DR, CD-38) were significantly lower in smear positive PTB patients following treatment, whereas a consistent decline in these markers was less apparent among smear negative PTB patients at the sixth month.

Conclusion

After six months of standard anti-TB therapy, persistent levels of activation of HLA-DR and CD-38 from PPD specific CD4+T cells in this study could indicate that those markers have little value in monitoring and predicting anti-TB treatment response in smear negative pulmonary TB patients in Ethiopian context.

Evaluation of Treatment Indications, Tuberculin Skin Test, and Bacillus Calmette-Guerin Vaccination Scars in the Cases of Latent Tuberculosis Infection Treatment

OBJECTIVES

The aim of our study was to evaluate the latent tuberculosis infection (LTBI) treatment application and to investigate if there is change between tuberculin skin test (TST) results according to bacillus Calmette-Guerin (BCG) scar numbers after LTBI treatment with isoniazid (INH).

MATERIAL AND METHODS

Data were collected from the LTBI treatment files from the dispensary of 2006. The results were statistically evaluated.

RESULTS

Latent tuberculosis infection was administered to 253 cases in 2006. The male/female case rate was 51/49. The age of most patients was under 15 years out of 14 cases. The mean age was 8.92±6.87 years (range, 0-84 years). One case had liver function test abnormality and INH was stopped in the first month of treatment. The completion rate of LTBI treatment was 95%. BCG vaccination rate was 93%. Active tuberculosis did not develop during the LTBI treatment in our study. Of all the cases, 221 scar numbers and TST were full. Of all cases 221 the scar numbers and TST value were full.TST of the 221 cases according to BCG vaccine scar numbers and indications were compared pre- and post-treatment with INH. Indications for LTBI treatment in these cases were close contact with smear-positive active pulmonary tuberculosis cases (n=77, 35%), TST-positive children aged <15 years (n=138, 62%), and the other (n=6, 3%) immunosuppressed patient cases. After treatment with INH, TST values decreased in the TST-positive children aged <15 years with one and 2 scars, with a statistically significant this result were found statistically significant (p<0.05).

CONCLUSION

The age of patients in most cases with LTBI treatment was under 15 years. The treatment completion rate and BCG vaccination rate were high. One case had liver function test abnormality. Active tuberculosis did not develop during the LTBI treatment. In the group with TST-positive children aged <15 years with one and 2 BCG vaccine scars, the decrease between pre- and post-treatment TST results showed a statistically significant difference.