Peptide-based radiopharmaceuticals targeting integrin α5β1 show promise for precise tumor diagnosis and treatment. However, current peptide-based radioligands that target α5β1 demonstrate inadequate in vivo performance owing to limited tumor retention. The use of PEGylation to enhance the tumor retention of radiopharmaceuticals by prolonging blood circulation time poses a risk of increased blood toxicity. Therefore, a PEGylation strategy that boosts tumor retention while minimizing blood circulation time is urgently needed. Here, we developed a PEGylation-enabled peptide multidisplay platform (PEGibody) for PR_b, an α5β1 targeting peptide. PEGibody generation involved PEGylation and self-assembly. [⁶⁴Cu]QM-2303 PEGibodies displayed spherical nanoparticles ranging from 100 to 200 nm in diameter. Compared with non-PEGylated radioligands, [⁶⁴Cu]QM-2303 demonstrated enhanced tumor retention time due to increased binding affinity and stability. Importantly, the biodistribution analysis confirmed rapid clearance of [⁶⁴Cu]QM-2303 from the bloodstream. Administration of a single dose of [¹⁷⁷Lu]QM-2303 led to robust antitumor efficacy. Furthermore, [⁶⁴Cu]/[¹⁷⁷Lu]QM-2303 exhibited low hematological and organ toxicity in both healthy and tumor-bearing mice. Therefore, this study presents a PEGibody-based radiotheranostic approach that enhances tumor retention time and provides long-lasting antitumor effects without prolonging blood circulation lifetime. The PEGibody-based radiopharmaceutical [⁶⁴Cu]/[¹⁷⁷Lu]QM-2303 shows great potential for positron emission tomography imaging-guided targeted radionuclide therapy for α5β1-overexpressing tumors.

Objective:To analyze the clinical value of serum 2019 novel coronavirus (2019-nCoV) immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies in the diagnosis of COVID-19.Methods:A total of 116 patients diagnosed with NCP in the First Affiliated Hospital of Hunan University of Chinese Medicine and the First Affiliated Hospital of Xiamen University were enrolled from January to February 2020 as the disease group. A total of 134 cases, including 84 non-NCP inpatients and 50 healthy individuals served as the control group. Serum samples from all subjects were collected. A fully-automated chemiluminescence immunoassay analyzer was used to detect the concentration of 2019-nCoV IgM and IgG antibodies in serum. The sensitivity and specificity of the 2019-nCoV IgM and IgG antibody single test and combined detection were compared using the χ 2 test. χ 2 test and Wilcoxon′s rank sum test were used to compare the positive rates and concentrations of IgM and IgG antibodies in NCP patients before and after their 2019-nCoV nucleic acid tests turning negative, respectively. The change trend of 2019-nCoV antibody concentration in the process of NCP patients was analyzed by Wilcoxon′s rank sum test. Results:The sensitivity of 2019-nCoV IgG (90.5%, 105/116) was higher than that of 2019-nCoV IgM (75.9%, 88/116), the difference was statistically significant (χ 2=8.91, P<0.05); The specificity of 2019-nCoV IgG (99.3%,133/134) was higher than that of 2019-nCoV IgM (94.0%, 126/134), the difference was statistically significant (χ 2=5.63, P<0.05). The sensitivity (89.7%,87/97) of 2019-nCoV IgM combined with IgG was higher than that of 2019-nCoV IgM, the difference was statistically significant (χ 2=6.89, P<0.05). The specificity (100%, 125/125) of 2019-nCoV IgM combined with IgG was higher than that of 2019-nCoV IgM, the difference was statistically significant (χ 2=7.70, P<0.05). After 2019-nCoV nucleic acid test converted to negative, the positive rate (9/17) and concentration [13.0 (4.9, 24.7) AU/ml] of serum 2019-nCoV IgM antibody were significantly lower than those when the nucleic acid test was positive, positive rate (15/17) and concentration [29.5 (14.0, 61.3) AU/ml], respectively (χ 2=5.10, Z=-3.195, both P<0.05). In the course of NCP, patients′ serum samples were collected from the first day of diagnosis to every three days, three times in total. The first 2019-nCoV IgM and IgG antibody concentrations [19.4 (12.4, 63.7) AU/ml, 105.8 (74.8, 126.1) AU/ml, respectively] were significantly higher than the second concentrations [15.8 (7.1, 40.3)AU/ml, 80.5 (66.7, 105.9) AU/ml], Z were-2.897,-3.179, both P<0.05. Conclusions:2019-nCoV IgG antibody has a good application value in the diagnosis of NCP. The concentration of 2019-nCoV IgM antibody has a certain correlation with the detection of 2019-nCoV nucleic acid. The combination of 2019-nCoV IgM and IgG antibodies with 2019-nCoV nucleic acid test may be the best laboratory index for the diagnosis of NCP at present.