Ribokinase screened from T7 phage displayed Mycobacterium tuberculosis genomic DNA library had good potential for the serodiagnosis of tuberculosis

High-performance immune diagnosis of tuberculosis: Use of phage display and synthetic peptide in an optimized experimental design

Immunoassays are practical and cost-effective approaches suitable for large-scale tuberculosis (TB) screening. This study identified new peptide mimotopes of Mycobacterium tuberculosis and applied them in the serodiagnosis of TB. Thereby, linear (X₁₅, X₈CX₈) and constrained (LX-4 and LX-8) phage display peptide libraries were screened with purified Immunoglobulin G antibodies from TB-positive patients, and eight mimotopes were selected. The mimotope peptides were screened using the SPOT-synthesis technique followed by immunoblotting. Peptides P.Mt.PD.4 and P.Mt.PD.7 demonstrated the highest binding affinity and were chemically synthesized and used as antigens for enzyme-linked immunosorbent assay (ELISA) assays. Experimental designs were used to optimize the assays and to assess each variable's influence. Peptide P.Mt.PD.7 was differentiated between positive and negative samples and achieved 100% sensitivity and specificity when tested on a 100-sera panel. Therefore, the selected peptide was applied to the ELISA assay as a screening method for diagnosing TB represents a potential tool for helping to combat the disease.

T7 Phage as an Emerging Nanobiomaterial with Genetically Tunable Target Specificity

Bacteriophages, also known as phages, are specific antagonists against bacteria. T7 phage has drawn massive attention in precision medicine owing to its distinctive advantages, such as short replication cycle, ease in displaying peptides and proteins, high stability and cloning efficiency, facile manipulation, and convenient storage. By introducing foreign gene into phage DNA, T7 phage can present foreign peptides or proteins site-specifically on its capsid, enabling it to become a nanoparticle that can be genetically engineered to screen and display a peptide or protein capable of recognizing a specific target with high affinity. This review critically introduces the biomedical use of T7 phage, ranging from the detection of serological biomarkers and bacterial pathogens, recognition of cells or tissues with high affinity, design of gene vectors or vaccines, to targeted therapy of different challenging diseases (e.g., bacterial infection, cancer, neurodegenerative disease, inflammatory disease, and foot-mouth disease). It also discusses perspectives and challenges in exploring T7 phage, including the understanding of its interactions with human body, assembly into scaffolds for tissue regeneration, integration with genome editing, and theranostic use in clinics. As a genetically modifiable biological nanoparticle, T7 phage holds promise as biomedical imaging probes, therapeutic agents, drug and gene carriers, and detection tools.

A systematic review of potential screening biomarkers for active TB disease

INTRODUCTION

The standard TB Four Symptom Screen does not meet the World Health Organization (WHO) ideal screening criteria for having greater than 90% sensitivity to identify active TB disease, regardless of HIV status. To identify novel screening biomarkers for active TB, we performed a systematic review of any cohort or case-control study reporting associations between screening biomarkers and active TB disease.

METHODS

We searched PubMed and Embase for articles published before October 10, 2021. We included studies from high or medium tuberculosis burden countries. We excluded articles focusing on C-reactive protein and lipoarabinomannan. For all included biomarkers, we calculated sensitivity, specificity and 95% confidence intervals, and assessed study quality using a tool adapted from the QUADAS-2 risk of bias.

RESULTS

From 8,062 abstracts screened, we included 79 articles. The articles described 302 unique biomarkers, including host antibodies, host proteins, TB antigens, microRNAs, whole blood gene PCRs, and combinations of biomarkers. Of these, 23 biomarkers had sensitivity greater than 90% and specificity greater than 70%, meeting WHO criteria for an ideal screening test. Among the eleven biomarkers described in people living with HIV, only one had a sensitivity greater than 90% and specificity greater than 70% for active TB.

CONCLUSION

Further evaluation of biomarkers of active TB should be pursued to accelerate identification of TB disease.

Mycoplasma genitalium Protein of Adhesion Promotes the Early Proliferation of Human Urothelial Cells by Interacting with RPL35

Mycoplasma genitalium is a newly recognized pathogen associated with sexually transmitted diseases (STDs). MgPa, the adhesion protein of Mycoplasma genitalium, is the main adhesin and the key factor for M. genitalium interacting with host cells. Currently, the long-term survival mechanism of M. genitalium in the host is not clear. In this study, a T7 phage-displayed human urothelial cell (SV-HUC-1) cDNA library was constructed, and the interaction of MgPa was screened from this library using the recombinant MgPa (rMgPa) as a target molecule. We verified that 60S ribosomal protein L35 (RPL35) can interact with MgPa using far-Western blot and co-localization analysis. According to the results of tandem mass tag (TMT) labeling and proteome quantitative analysis, there were altogether 407 differentially expressed proteins between the pcDNA3.1(+)/MgPa-transfected cells and non-transfected cells, of which there were 6 downregulated proteins and 401 upregulated proteins. The results of qRT-PCR demonstrated that interaction between rMgPa and RPL35 could promote the expressions of EIF2, SRP68, SERBP1, RPL35A, EGF, and TGF-β. 3-(4,5)-Dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide bromide (MTT) assays corroborated that the interaction between rMgPa and RPL35 could promote SV-HUC-1 cell proliferation. Therefore, our findings indicated that the interaction between rMgPa and RPL35 can enhance the expressions of transcription-initiation and translation-related proteins and thus promote cell proliferation. This study elucidates a new biological function of MgPa and can explain this new mechanism of M. genitalium in the host.

Combining the advantages of prokaryotic expression and T7 phage display systems to obtain antigens for antibody preparation

The gene encoding the phage major capsid protein 10A was cloned into the prokaryotic expression vector pET24a, and a 6XHis-tag was fused to the 3'-end of the 10A gene to verify complete expression. The recombinant plasmid was transformed into Escherichia coli (E. coli) BL21 (DE3) cells, and 10A expression was induced by IPTG. SDS-PAGE and Western blot were used to confirm the target protein expression. The T7Select10-3b vector was added to the cultured bacteria expressing 10A at a multiplicity of infection (MOI) ranging from 0.01 to 0.1, and complete lysis of the bacteria was monitored by absorbance changes in the medium. The recombinant phage (reP) was harvested by PEG/NaCl sedimentation and resuspended in PBS. ELISA was performed to verify the presence of the 6XHis-tag on the surface of reP. The 10A-fusion expression vectors (pET10A-flag, pET10A-egfp, and pET10A-pct) were constructed, and fusion proteins were expressed and detected by the same method. The corresponding rePs (reP-Flag, reP-EGFP, and reP-PCT) were prepared by T7Select10-3b infection. After the expression of the peptides/proteins on the reP surfaces was confirmed, reP-Flag and reP-PCT were used to immunize mice to prepare anti-Flag and anti-PCT antibodies. The results showed that rePs prepared using the 10A-fusion vector and T7Select10-3b can be used as antigens to immunize mice and prepare antibodies. This method may be able to meet the rapid antigen preparation requirements for antibody production. Notably, the recombinant phage (reP) described in this study was obtained by the sedimentation method from T7Select10-3b-infected E. coli BL21 (DE3) cells carrying the major capsid protein 10A expression vector or 10A-fusion protein vector.