Objective To establish a rapid immunological detection method for MPT64 protein based on red microspheres and select highly-sensitive and highly-specific antibody pairs.Methods A His-tagged prokaryotic expression vector was constructed for expression of MPT64 protein that was used to immunize New Zealand white rabbits after purification and validation.Peripheral blood mononuclear cells(PBMCs)were isolated from the rabbits,and antigen-specific B cells expressing antibodies were sorted using single B-cell flow cytometry.mRNA in B cells was reverse-transcribed into cDNA,and paired antibody heavy-and light-chain sequences were amplified via nested PCR.Expression vectors were constructed,and recombinant antibodies were produced in Expi293F cells.Fluorescent immunochromatography was employed to screen for matched antibody pairs.The selected antibodies were used to establish a rapid detection method based on red microsphere immunochromatography.Results Ten high-affinity monoclonal antibodies against MPT64 were generated.Two antibody pairs were selected for MPT64 immunodetection that reached a sensitivity of 0.0125 ng/mL.Conclusion High-affinity rabbit monoclonal antibodies against MPT64 are obtained via single B-cell technology,and a rapid red microspheres-based immunodetection method is established,enabling highly sensitive detection of Mycobacterium tuberculosis MPT64 protein.

Objective To compare the efficacy and safety of levofloxacin 750 mg for 5 days versus 500 mg for 7‐14 days intravenous (IV ) infusion in the treatment of community‐acquired pneumonia (CAP ) . Methods This study was a multi‐center , randomized , open‐label , non‐inferiority , controlled clinical trial .The CAP patients were randomized to receive levofloxacin 750 mg IV daily for 5 days or levofloxacin 500 mg IV daily for 7‐14 days .The clinical symptoms , laboratory tests , imaging results and microbiology data were collected and compared between the two treatment groups in terms of efficacy and safety .Results A total of 241 patients were enrolled in this clinical trial from 10 study centers .Among these patients ,223 were eligible for full analysis set (FAS) analysis ,including 111 in 750 mg group and 112 in 500 mg group .Of the 223 patients in FAS ,211 were eligible for per‐protocol set (PPS) analysis ,including 107 in 750 mg group and 104 in 500 mg group .Two hundred and forty‐one patients were included in safety set (SS) ,including 121 patients in 750 mg group and 120 in 500 mg group .The median treatment duration was 5 .0 days in 750 mg and 9 .0 days in 500 mg group .The median total dose was 3 750 mg in 750 mg group and 4 500 mg in 500 mg group .The overall efficacy rate was 86 .2% in 750 mg group and 84 .7% in 500 mg group in terms of FAS at visit 4 ,which suggested that the efficacy of 750 mg group was non‐inferior to 500 mg group .Of the 111 FAS patients in 750 mg group ,40 were bacteriological evaluable ,and 41 strains of pathogens were isolated .Forty‐nine of the 112 FAS patients in 500 mg group were bacteriological evaluable ,and 51 bacterial strains were obtained .The bacterial eradication rate was 100% in both groups .The clinical treatment efficacy rate for atypical pathogens was 100% in both groups .In 750 mg group ,the most common clinical adverse drug reactions (ADRs) were injection site adverse reactions including injection site pruritus ,pain and hyperemia .The other common ADRs were insomnia ,nausea ,skin rash .The most common drug‐related laboratory abnormalities were neutrophil percentage decreased , decreased white blood cell (WBC ) count , alanine aminotransferase (ALT) and aspartate aminotransferase (AST) elevation .Most of the ADRs were mild in severity and well‐tolerated .The safety profile of the two treatments was comparable in terms of the drug‐related treatment discontinuation and the incidence of ADRs .Conclusions The short‐course regimen of levofloxacin 750 mg IV for 5 days is at least as effective and well tolerated as the long‐course regimen of 500 mg IV for 7‐14 days in treatment of CAP .