Objective To evaluate the immunoprotection by the inactivated whole bacteria(IWB) of Stenotrophomonas maltophilia K279a in mice.Methods Mice were immunized by inactivated whole bacteria of S.maltophilia K279a made from formaldehyde.When the indicated the antibody titer of the mice reached the require level, the protective effect of the IWB was evaluated by performing the opsonophagocytic killing test in vitro and the poison attack experiments in vivo. Results It was found that IgG in serum of the immunized mice measured by ELISA was significantly increased after the second immune enhancement, and antiserum in vitro had strong phagocytic effect.Meanwhile, immunoprotection of the immunized groups was also significantly increased when challenged by S.maltophilia K279a.Conclusion Effective humoral immune response can be predominantly induced by the inactivated whole bacteria of S.maltophilia K279a, providing protection against challenge by S.maltophilia K279a in BALB/c mice.

AIM: The main chemical components of Yufang Fangji II (Hubei Fang) of COVID-19 were studied systematically and combined with network pharmacology to provide a reference for the study of its effective substances. METHODS: Ultra high-performance liquid chromatography quadrupole time of flight mass spectrometry (UHPLC-Q-TOF/MS) was applied to identify the absorbed components of the prescription in rat plasma. TCMSP database and Swiss Target Prediction data platform were used to predict the target of the identified blood components, and network visualization software Cytoscape 3.7.2 was used draw the association network diagram, and GO enrichment analysis and KEGG pathway enrichment analysis were conducted for the key targets. With the help of CB-Dock online molecular docking platform, the molecular docking of key targets and blood entering compounds was carried out, and the docking combination with good affinity value was displayed by ligplot software to verify the preventive effect of Yufang Fangji II on COVID-19. RESULTS: A total of 52 chemical components identified in the prescription, in which 13 components were absorbed in the rat plasma as the prototype, and they were from Astragalus membranaceus, Atractylodes macrocephala, Saposhnikoviae Radix, Lonicerae Japonicae Flos, and Citri Reticulatae Pericarpium, respectively. These compounds were recognized to act on 17 core targets, including mapk3, TNF and other targets related to inflammation, MPO and other targets related to oxidative stress, VEGFR, KDR and other targets related to vascular endothelium. The results of molecular docking showed that the absorbed components had good binding activity with the key targets. CONCLUSION: Compounds in Yufang Fangji II are involved in regulating inflammation, oxidative stress, vascular and cellular physiological activities, which have preventive effects on COVID-19 through regulating IL-17, PI3K Akt, MAPK and other pathways.