Molecular Cloning and Immunogenicity Evaluation of PpiC, GelE, and VS87_01105 Proteins of Enterococcus faecalis as Vaccine Candidates

Background

Among the enterococci strains, Enterococcus faecalis is considered as one of the important nosocomial pathogens affecting immunocompromised patients. In this study, the immunogenicity of PpiC, GelE, and VS87_01105 proteins against enterococcal infection was investigated in a mice model.

Methods

The genes encoding these proteins were cloned into pET21a expression vector, and the recombinant proteins were produced. Mice and rabbits were immunized with the purified recombinant proteins, and subsequently, mice were challenged with E. faecalis for the evaluation of their survival and bacterial clearances. The antibody responses to recombinant proteins were determined by ELISA assay, and opsonophagocytic activities of the antibodies were also measured. Passive immunization was performed using purified antibodies. Mice were challenged, and their survival and bacterial clearance were determined.

Results

Immunized mice with PpiC, GelE, and VS87_01105 recombinant proteins showed 80%, 70%, and 40% survival rate, respectively. The survival rates among passively immunized mice that received 500 µg of IgG fraction in 100 µl PBS buffer of each of anti-PpiC, anti-GelE, and anti-VS87_01105 were 60%, 50%, and 20%, respectively. The rates of opsonization with anti-PpiC, anti-GelE, and anti-VS87_01105 antibodies at 1/10 dilution were 77%, 64%, and 23%, respectively.

Conclusion

Based on our findings, PpiC, and GelE proteins can protect the mice against E. faecalis ATCC 29212 and effectively induce a protective antibody response. Thus, these proteins could be used as an additional therapeutic tool against enterococcal infections. Further studies to determine the role of PpiC in ligand binding and demonstration of epitope mapping may establish a credible target for vaccination.

Comparison of MIRU-VNTR genotyping between old and fresh clinical samples in tuberculosis

Background: Twenty-four loci mycobacterial interspersed repetitive unit-variable number tandem repeat analysis (MIRU-VNTR) is extensively used for genotyping and detection of polyclonal infections in tuberculosis. The aim of the present study was to compare the direct and indirect MIRU-VNTR genotyping and detection of polyclonal infections between old and fresh clinical samples. Method: Two series of TB samples were collected for comparison. After genomic DNA extraction from clinical samples and their respective cultures, 24 loci MIRU-VNTR was performed. Results: In the 14 old samples, no mixed infections were observed, in clinical samples and their respective cultures. In nine fresh samples, 44.4% of mixed infection was observed in the clinical samples, but no mixed infections were observed in their respective cultures. Surprisingly, in the old samples, 92.86% of samples (13/14) had an allelic change between clinical samples and their respective cultures. On the other hand, in fresh samples, only one sample (1/9) had an allelic change between clinical samples and their respective cultures. Conclusions: We concluded that 24 loci MIRU-VNTR undoubtedly is successful in direct genotyping of clinical samples, especially for the fresh samples. However, selecting starting material, such as clinical sample or respective culture can be controversial for the old samples. Regarding polyclonal infections, the fresh samples gives us a better view to detect these infections, especially in the clinical sample.

Evaluating the clinical significance of nontuberculous mycobacteria isolated from respiratory samples in Iran: an often overlooked disease

Purpose

Nontuberculous mycobacteria (NTM) infection is an increasing problem worldwide whose clinical significance is still largely unknown. The aim of this study was to investigate the epidemiology of NTM infection from respiratory samples and to determine their clinical significance.

Patients and methods

This cross-sectional study was performed on 7,825 clinical samples from December 2015 to December 2017. Detection was conducted using phenotypic and genotypic (hsp65 PCR-RFLP, rpoB, and 16S rRNA genes sequencing) methods. All clinical information including symptoms and radiological findings was extracted from patients’ records.

Results

A total of 478 were confirmed to have respiratory samples which were culture positive for mycobacteria, with the prevalence of NTM infection obtained as 53 (11.1%). Overall, Mycobacterium (M.) fortuitum was the most frequent NTM isolate, followed by M. simiae, M. kansasii, M. gordonae, and M. conceptionense. There was a relationship between NTM isolates and gender (P=0.039), symptoms (P=0.048), and radiographic findings (P=0.013). Bronchiectasis, infiltration, and cavitary lesion were the most frequent radiological findings in M. fortuitum, M. simiae, and M. kansasii, respectively, with cough being the most frequent symptom.

Conclusion

We reported five different NTM isolates in respiratory samples with a high frequency of M. fortuitum. NTM infections may play an important role in causing pulmonary disease and in tuberculosis management in endemic settings. Nevertheless, more studies are required to further examine the clinical significance of NTM isolates.

Truncated Core/NS3 Fusion Protein of HCV Adjuvanted with Outer Membrane Vesicles of Neisseria meningitidis Serogroup B: Potent Inducer of the Murine Immune System

Background

A licensed vaccine against hepatitis C virus (HCV) has not become available to date. The stability and antigenicity of a targeted synthesized recombinant fusion protein consisting of a truncated core and NS3 (rC/N) of HCV had been predicted. Although safe antigens, recombinant proteins are not efficacious vaccines without adjuvants. The present study evaluated the immunogenicity of rC/N as a bipartite antigen accompanied by Neisseria meningitidis serogroup B outer membrane vesicles (NMB OMVs) in BALB/c mice.

Methods

The NMB OMVs were produced and evaluated accurately. The administrations were as follows: rC/N-OMV, rC/N-Freund’s complete/incomplete adjuvant (CIA), rC/N-MF59, rC/N, OMV, MF59, and PBS. The production of Th1 (IFN-γ, IL-2)/Th2 (IL-4)/Th17 (IL-17) cytokines and granzyme B (cytotoxic indicator) by splenic mononuclear cells and the humoral concentration of total IgG/IgG1 (Th2)/IgG2a (Th1) in sera of mice were measured using mouse ELISA kits.

Results

Concentrations of Th1/Th2/Th17 cytokines, granzyme B, and immunoglobulins in the spleens and sera of immunized mice, which had received antigen plus each adjuvant (rC/N-OMV, rC/N-Freund’s CIA, and rC/N-MF59), significantly raised compared to the controls (rC/N, OMV, MF59, and PBS). Th1-type responses were dominant over Th2-type responses in vaccinated mice with rC/N-OMV, and Th2 type responses increased dominantly in vaccinated mice with rC/N-MF59 (p < 0.05).

Discssion

NMB OMVs were able to increase Th1 immune responses dramatically more than MF59 and Freund’s CIA. The formulation of rC/N with NMB OMVs showed its ability to induce Th1, Th2, and Th17 immune responses. rC/N-NMB OMVs is a promising approach for the development of an HCV therapeutic vaccine.

Occult hepatitis C virus infection in patients with beta-thalassemia major: Is it a neglected and unexplained phenomenon?

Occult hepatitis C virus (HCV) infection (OCI) is described as the presence of viral genome in both hepatocytes and peripheral blood mononuclear cells (PBMCs) despite constant negative results on serum HCV RNA tests. Beta-thalassemia major (BTM) describes a group of inherited blood diseases. Patients with BTM require repeated blood transfusions, increasing the risk of exposure to infectious agents. We aimed to assess the prevalence of OCI in Iranian BTM patients and to identify the role of host factors in OCI positivity. A total of 181 BTM patients with HCV negative markers were selected. HCV RNA was tested in PBMCs using nested polymerase chain reaction assay. The positive samples were then genotyped via restriction fragment-length polymorphism (RFLP) and 5'-untranslated region sequencing. Six (3.3%) out of 181 BTM patients had viral HCV genomes in PBMC samples. Three (50.0%), two (33.3%), and one (16.7%) out of these six patients were infected with HCV-1b, HCV-1a, and HCV-3a, respectively. OCI positivity was significantly associated with the serum level of uric acid (P = 0.045) and ABO blood group (P = 0.032). Also, OCI patients had unfavorable IFNL3 rs12979860 TT, IFNL3 rs8099917 GG, IFNL3 rs12980275 GG, and IFNL4 ss469415590 ∆G/∆G genotypes. In conclusion, we indicated the low frequency of OCI in BTM patients. Nevertheless, more attention is warranted considering the importance of this infection. Also, further studies are necessary to determine the actual prevalence of OCI among BTM patients in Iran.

Host genetic factors and clinical parameters influencing the occult hepatitis C virus infection in patients on chronic hemodialysis: Is it still a controversial infection?

AIM

The presence of occult hepatitis C virus (HCV) infection (OCI) is still controversial, however, this infection cannot be ignored. Therefore, the current study aimed at assessing the OCI frequency in patients on chronic hemodialysis (CHD) and also evaluating the association between OCI incidence with clinical parameters and interferon lambda 3/4 (IFNL3/4) gene polymorphisms.

METHODS

A total of 515 patients on CHD and HCV negative markers were selected. Plus- and minus-stranded HCV-RNA was tested in peripheral blood mononuclear cell samples by reverse transcription-polymerase chain reaction and then genotyped using the restriction fragment length polymorphism method.

RESULTS

The frequency of OCI was 11.3% in patients on CHD. Among 58 patients with OCI, 25.8%, 62.1%, and 12.1% were infected with HCV-1a, HCV-1b, and HCV-3a, respectively. The mean alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase levels were 31.9 ± 24.8, 32.3 ± 19.1, and 171.6 ± 88.9, respectively. None of the patients with OCI had a history of liver disease. Multivariate logistic regression analysis indicated that cholesterol, triglyceride, low-density lipoprotein, 25-hydroxyvitamin D, platelets, duration of hemodialysis, HCV subtypes, IFNL3 rs12979860 TT, IFNL3 rs8099917 GG, IFNL3 rs12980275 GG, and IFNL4 ss469415590 ΔG/ΔG genotypes were associated with OCI.

CONCLUSION

There was a moderate prevalence of OCI in Iranian patients on CHD. The current study findings indicated that this infection was associated with clinical parameters and unfavorable genotypes of IFNL3 single nucleotide polymorphisms and IFNL4 ss469415590. Further studies are required to determine the correlation between OCI incidence with clinical parameters and host genetic factors.

Evaluation of antibody responses to outer membrane vesicles (OMVs) and killed whole cell of Vibrio cholerae O1 El Tor in immunized mice

BACKGROUND AND OBJECTIVES

Cholera disease remains an important global health problem affecting 3-5 million subjects worldwide. Outer membrane vesicles (OMVs) have been found in a variety of Gram-negative bacteria and act as protective transport vesicles. The aim of this study was to evaluate Immune responses against Vibrio cholerae O1 El Tor clinical strain OMV and compare it with killed whole cell (KWC), complex of (KWC-OMV) as well as the internationally licensed oral cholera vaccine, Dukoral, in serum and intestinal secretions of mice.

MATERIALS AND METHODS

OMVs were prepared by using modified detergent-centrifugation procedure from V. cholerae O1 El Tor clinical strain from 2005 outbreak. The ultrastructure and content of OMVs were investigated via the Scanning Electron Microscopy (SEM) and SDS-PAGE analysis. Three doses of oral immunization were adjusted and total IgG and IgA in serum and intestinal secretion were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Extracted OMVs from the V. cholerae were spherical vesicles with a size ranging from 10 to 300 nm. OMV-immunized mice showed an increased level of total IgG and IgA both in serum and intestinal secretion when compared to the negative controls. Also, there existed a higher level of secretory IgA than the total IgG, suggesting the most of protection against V. cholerae colonization provided by sIgA.

CONCLUSION

Our findings revealed that oral immunization with V. cholerae OMVs might induce a long-term immunity, especially when administered in combination with KWC. This study tested the adjuvant activity of OMVs and may be useful in future nano vaccine research.

Induction effects of Faecalibacterium prausnitzii and its extracellular vesicles on toll-like receptor signaling pathway gene expression and cytokine level in human intestinal epithelial cells

A single layer of epithelial cells creates an interface between the host and microorganisms colonizing the gastrointestinal tract. In a healthy intestine, commensal bacteria and their metabolites can interact with epithelial cells as they are identified by Toll-like receptors (TLRs); This interaction results in homeostasis and immune responses. The present study aimed at evaluating Faecalibacterium prausnitzii- and extracellular vesicles (EVs)-induced expression of involved genes in TLRs signaling pathway and cytokines production in Caco-2 cell line. In this study, Caco-2 cell line was treated with F. prausitzii and its EVs. Using the protein levels of 12 cytokines were also evaluated by ELISA assay. F. prausnitzii induced upregulation in FOS, JUN, TNF-α, NFKB1, TLR3, IKBKB and CD86 genes. Furthermore, stimulation of Caco-2 cells with EVs derived from F. prausnitzii induced upregulation of CXCL8, CCL2, FOS, MAP2K4, TLR7, TLR3, IRF1, NFKBIA and TNF-α genes. Based on ELISA assay, Caco-2 cells treated with F. prausnitzii and its EVs showed a significant increase in TNF-α, IL-4, IL-8, and IL-10 expression and significant decreased in IL-1, IL-2, IL-6, IL-12, IL-17a, IFN-γ compared to the control group (P < 0.05). In conclusion, EVs derived from F. prausnitzii showed greater efficacy in decreasing the inflammatory cytokines and increasing the anti-inflammatory cytokines, compared to F. prausnitzii. Our findings can be used as a theoretical model for EVs application in the potential treatment of inflammation.

The significance of microbiome in personalized medicine

Considering the important role of microbiome, many of current investigations have focused on its beneficial aspects. Although, research explores new dimensions of the impact of microbiome and examines the differences in patients and healthy individuals for identifying biomarker patterns, but limited information is available, and investigation in this field seems to be of great value. On the other hand, new therapeutic approaches, called personalized medicine, have opened a new window in medical science, and the association between microbiome and personalized medicine seems to be one of the most interesting aspects of the subsequent research, and has a pivotal perspective on the treatment of diseases such as cancer. Accordingly, given the novelty of the relationship between these two axes, there are very few studies in this regard. The presence of specific strains may have the ability to modulate cancer progression and therapeutics; this increases the likelihood of precision medicine in relation to microbiota, in terms of treatment and prognosis, and therefore, microbiota is a next generation medicine and may develop a novel therapeutic action in this field.

Scrutinizing the drug resistance mechanism of multi- and extensively-drug resistant Mycobacterium tuberculosis: mutations versus efflux pumps

Background

In order to shorten the course of treatment and its effectiveness, it is essential to gain an in-depth insight into the drug resistance mechanisms of Mycobacterium tuberculosis (M. tuberculosis).

Methods

In this study, we evaluated the contribution of 26 drug efflux pumps plus target gene mutations to the drug resistance levels in multi-drug resistant (MDR)/pre-extensively drug-resistant (pre-XDR)/extensively drug-resistant (XDR) and mono-drug resistant clinical isolates of M. tuberculosis. The panels of 25 M. tuberculosis clinical strains were characterized for drug resistance-associated mutations with whole-genome sequencing and antibiotic profiles in the presence and absence of efflux inhibitor verapamil (VP).

Results

Different MICs were observed for the same target gene mutations. Out of the 16 MDR/pre-XDR/XDR isolates, 6 (37.5%) and 3 (18.8%) isolates demonstrated a significant decrease in rifampicin (RIF) MIC and isoniazid (INH) MIC due to the VP exposure (64 μg/mL), respectively. Susceptibility to RIF was fully restored in two isolates after VP exposure. Moreover, the efflux pump genes of Rv2938, Rv2936, Rv1145, Rv1146, Rv933, Rv1250, Rv876, Rv2333, Rv2459, Rv849, and Rv1819 were overexpressed in the presence of anti-TB drugs, showing the contribution of these efflux pumps to the overall resistance phenotype.

Conclusions

Our results clearly showed that efflux systems, besides spontaneous mutations, play a role in the development of INH/RIF resistance. In addition, although VP was effective in reducing the expression of some efflux pumps, it was not very successful at the phenotypic level.

Mycobacterium avium Complex Extracellular Vesicles Attenuate Inflammation via Inducing IL-10

Mycobacterium avium complex (MAC) is an ubiquitous acid-fast bacterium. MAC cell wall and membrane release extracellular vesicles (EVs) into different media. The immunogenic effects of EVs isolated from MAC remain unknown. The aim of this study was to determine the EVs effect on macrophage cytokine production. MAC EVs were extracted and purified using differential centrifuges also known as Claassen’s method, with some modifications. After protein analysis of EVs, and scanning electron microscopy (SEM), the EVs were injected into BALB/c mice for in vivo experiments. The concentration of interferon gamma (IFN-γ) and interleukin 10 (IL-10) in the spleen immune cell culture was measured by sandwich ELISA. We for the first time showed that MAC can naturally produce EVs. The extraction method was technically-feasible, efficient and affordable. The SEM analysis showed that EVs diameter was similar to other studies on mycobacteria, and EVs maintained their spatial characterization. The results of the cytokine assays indicated that EV-treated cells secreted IL-10 (P = 0.034) but not IFN-γ (P = 0.037). Our findings suggest that EVs of M. avium could have anti-inflammatory effects. They can be used as a suppressor or regulator of inflammation via IL-10. The replication of the anti-inflammatory response of MAC EVs in future studies may indicate a new therapeutic agent for inflammation.

Evaluation the Effect of Royal Jelly on the Growth of Two Members of Gut Microbiota; Bacteroides fragillis and Bacteroides thetaiotaomicron

Objective: In this study the effect of Royal jelly on the growth of two important members of Bacteroides spp.; Bacteroides fragilis and Bacteroides thetaiotaomicron, was evaluated. Also the physicochemical properties and cytotoxicity effects of Royal jelly on Caco-2 cell line as gastrointestinal epithelial cell model, assessed. Methods : Bacteria, Bacteroides fragilis and Bacteroides thetaiotaomicron were grown on brain heart infusion (BHI) broth medium supplemented with Royal jelly in 3 different concentrations (2.5, 5 and 10% v/v), both of the bacteria (1.5×108 cfu/mL) were inoculated to BHI broth contained Royal jelly in anaerobic condition. To calculate the bacterial optical density (OD), the absorbance was measured at 600 nm after an overnight. Also Caco-2 cells, was used to study the effects of Royal jelly on epithelial cell viability, and the Physicochemical properties consist of  total proteins, polysaccharides, phenolic compounds, total lipids, ash and moisture by UV-VIS spectrophotometric and gravimetric methods were evaluated . Results: The growth of B. fragillis and B. thetaiotaomicron were increased by Royal jelly (2.5, 5 and 10% v/v concentrations) and the results indicated that Royal jelly increased the growth of bacteria in a dose dependent manner (p<0.001). In addition MTT assay showed more than 95% viability of Caco-2 cells treated with Royal jelly. The Iranian Royal jelly sample contains 59.01% water, 11.57% proteins, 12% lipids, 12.63 % polysaccharide and 5% mineral. Conclusion: The present study showed that Royal jelly has a potential effect in the  preserving gut microbiota  and it is suggested that Royal jelly as a complementary and alternative medicine can be used to treatment diseases are associated  with gut microbiota- host interactions and immune regulating. Although we need to expand our knowledge by designing clinical trials to confirm the therapeutic effects of Royal jelly on gut microbiota modulation as a barrier function.

Cellular immune response in MDR-TB patients to different protein expression of MDR and susceptible Mycobacterium tuberculosis: Rv0147, a novel MDR-TB biomarker

Tuberculosis (TB) is a crucial public health problem with prevalence of multidrug resistant (MDR) rising. An accurate TB biomarker is urgently needed to monitor the response to treatment in patients with MDR tuberculosis. To analyze interaction between selected MDR-TB purified protein and immune cells, dendritic cells from MDR-TB patients and healthy subjects were stimulated by 55KDa protein fractions (Rv0147). The purified proteins identified by proteomic techniques (two-dimensional gel electrophoresis, mass spectrometry) and peptide sequences are known to bind a MHC class I alleles which are extracted from the Immune Epitope Database and Analysis Resource database ( www.iedb.org ). T cells were isolated from PBMC by negative selection and cells were cultured in RPMI-1640 at 37 °C and 5% CO₂. Cell culture was assayed for cytokine IL-10 and INF-γ by ELISA. We found that INF-γ production was significantly (335 ± 35.5 pg/ml, P ˂ 0.05) upregulated after protein candidate (Rv0147) stimulation by dendritic cells from MDR-TB patients, whereas IL-10 production was greatly reduced compared with production in healthy subjects (212 ± 9.94 pg/ml, P ˂ 0.05). In fact, the purified protein, Rv0147, stimulated dendritic cells from MDR-TB patients, failed to produce IL-10 and directly stimulates INF-γ production by T cells. These results suggest that the purified protein, Rv0147, may stimulate Th1 type protective cytokine response in MDR-TB patients but not in normal subjects. The production of INF-γ but not IL-10 in the presence of purified protein, Rv0147, may be shifted to Th1 responses in MDR-TB patients and supports its potential as protein vaccine candidates against TB.

The effect of saturated and unsaturated fatty acids on the production of outer membrane vesicles from Bacteroides fragilis and Bacteroides thetaiotaomicron

AIM

The aim of present study is to investigate the effect of fatty acids on the outer membrane vesicles (OMVs) produced by Bacteroides spp.

BACKGROUND

Bacteroides spp. is the important member of Gut microbiota that employ OMVs production for interact with host. Besides, dietary fatty acids could influence on determination of gut microbiota composition and immune response. In this regard, we evaluated the effect of fatty acids on the growth and OMVs production of Bacteroides fragilis and Bacteroides thetaiotaomicron.

METHODS

B. fragilis and B. thetaiotaomicron were grown on BHI broth with and without palmitic and palmitoleic acids as saturated and unsaturated fatty acids, respectively. OMVs were extracted using multiple centrifugation and tris-ethylene diamine tetra acetic acid (EDTA)-Sodium deoxy cholate buffers. Physicochemical properties of OMVs were detected by electron microscopy (SEM), Bradford Coomassie brilliant blue assay and SDS-PAGE. Data were analyzed with One-way ANOVA using SPSS.

RESULTS

The growths of both Bacteroides were significantly increased by palmitic acid. Nevertheless, palmitoleic acid had no significant effect on them. Palmitic acid significantly decreased and increased the production of B. fragilis OMVs at low and high concentration, respectively. However, the production of B. thetaiotaomicron OMVs was not significantly affected by palmitic acid. Although palmitoleic acid had a significant decreasing effect on the production of B. fragilis OMVs, it significantly increased the production of B. thetaiotaomicron OMVs at low concentration.

CONCLUSION

In conclusion we reported that palmitic acid had a stimulatory effect on the growth of B. fragilis and B. thetaiotaomicron and had a dose dependent effect on the production of B. fragilis OMVs. Also producing of B. thetaiotaomicron OMVs was affected by palmitoleic acid in a dose dependent manner.

Comparative study of effect of Akkermansia muciniphila and its extracellular vesicles on toll-like receptors and tight junction

AIM

We assessed effect of Akkermansia muciniphila and its extracellular vesicles on toll-like receptors and tight junction expression in human epithelial colorectal adenocarcinoma cells (Caco-2).

BACKGROUND

The intestinal microbiota plays an important role in the intestinal homeostasis through its metabolites and derivatives. Interacting with immune cells and intestinal epithelial pattern recognition receptors (PRRs), intestinal microbiota regulates the function of the digestive barrier and inflammation caused by the metabolic diseases.

METHODS

A. muciniphila was cultured on a mucin-containing medium and its EVs was extracted by ultracentrifugation. This bacterium was treated in the MOI=10 and its EVs at the concentrations of 0.1, 0.5 and 5 µg on Caco-2 cells. After 24 hours, the expression of tight junction and toll-like receptor genes were investigated by quantitative real time PCR method.

RESULTS

A. muciniphila increased the expression of tlr2 and tlr4. However, EVs at all of the concentrations showed a decrease in tlr4 expression. EVs at the concentrations of 0.1 and 0.5 µg/ml decreased the expression of tlr2. A. muciniphila significantly increased the expression of ocldn and cldn4. Both this bacterium and EVs increased the expression of zo2 in the cell line. Furthermore, this data show that A. muciniphila derived EVs have a dose-independent effect on Caco-2 cells.

CONCLUSION

This preliminary research shows A. muciniphila and its EVs both may increase the integrity of the intestinal barrier. A. muciniphila derived EVs also reduces the inflammation so that EVs of this bacterium can be used as an appropriate target for the treatment of metabolic syndrome and inflammatory bowel diseases.

Evaluation of the expression of cytokines and chemokines in macrophages in response to rifampin-monoresistant Mycobacterium tuberculosis and H37Rv strain

Macrophages are the primary phagocytes in the lungs and a part of the host defense system against Mycobacterium tuberculosis (Mtb), involved in the primary immune response. While several studies have assessed the effects of resistance to rifampin on Mtb physiology, the consequences of mutations in genes encoding the beta subunit of RNA polymerase (rpoB) for host-pathogen interactions remain poorly understood. In this study, rifampin-monoresistant (RMR) Mtb and H37Rv strains were used to infect the THP-1-derived macrophages. Real-time quantitative reverse transcription PCR assay was carried out to determine mRNA expression in 84 cytokine and chemokine genes. Production of specific cytokines and chemokines was measured by ELISA assay. In conclusion, the current study shed more light on the fitness cost of RMR strain and the potential effects of rpoB gene mutations on Mtb-host interactions. These results initially demonstrate that the Mtb carrying the rpoB-S450L can modulate macrophage responses to mediate bacterial survival.