Annexin A2 is a Ca 2+ regulated protein belonging to the Annexin family and is found in the cytoplasm and cell membrane. It can exist in a monomeric form or in a heterotetrameric form with the S100A10 dimer. The research on Annexin A2 in tumours is currently active, and studies on its role in pathogen infection are increasing. Annexin A2 plays a crucial role in the life cycle of viruses by mediating adhesion, internalization, uncoating, transport, and release. In the case of parasites, bacteria, mycoplasma, fungi, and other pathogens, Annexin A2 binds to the ligand on the pathogen, which mediates the pathogen’s adhesion to the host cell, ultimately leading to infection and damage to the host. Furthermore, some studies have developed biological or chemical drugs that target Annexin A2, which have demonstrated promising anti-infective effects. Thus, targeting Annexin A2 may present a promising therapeutic approach for the treatment of diverse infectious diseases. In summary, this paper provides an overview of Annexin A2 and its role in various pathogens. It highlights its regulation of pathogen infection and its potential as a therapeutic target for the treatment of infectious diseases.

Mycoplasma fermentans can cause respiratory diseases, arthritis, genitourinary tract infections, and chronic fatigue syndrome and have been linked to the development of the human immunodeficiency virus. Because mycoplasma lacks a cell wall, its outer membrane lipoproteins are one of the main factors that induce inflammation in the organism and contribute to disease development. Macrophage-activating lipopeptide-2 (MALP-2) modulates the inflammatory response of monocytes/macrophages in a bidirectional fashion, indirectly enhances the cytotoxicity of NK cells, promotes oxidative bursts in neutrophils, upregulates surface markers on lymphocytes, enhances antigen presentation on dendritic cells and induces immune inflammatory responses in sebocytes and mesenchymal cells. MALP-2 is a promising vaccine adjuvant for this application. It also promotes vascular healing and regeneration, accelerates wound and bone healing, suppresses tumors and metastasis, and reduces lung infections and inflammation. MALP-2 has a simple structure, is easy to synthesize, and has promising prospects for clinical application. Therefore, this paper reviews the mechanisms of MALP-2 activation in immune cells, focusing on the application of MALP-2 in animals/humans to provide a basis for the study of pathogenesis in Mycoplasma fermentans and the translation of MALP-2 into clinical applications.

Backgroud:The COVID-19 pandemic has swept the globe since 2019, threatening people's health. Many studies indicate that infection is closely related to immune response disorder. We searched for potential immune-related biomarkers through systems biological analysis, and performed immune infiltration analysis on relevant data. Methods and findings: We used CIBERSORT to analyze the blood transcriptomics data of the controls, the mild COVID-19 patients, and the severe COVID-19 patients. And we further obtained the essential infiltration immune cells of COVID-19 by the Wilcoxon test and LASSO algorithm. Then we used a limma package to find significant DE-IRGs. The GO and pathways analysis of these important immune genes were also applied. Subsequently, we used STRING and Cytoscape to screen hub genes and evaluated their value as a potential biomarker according to their expression at different stages and the ROC curve. Moreover, the results were verified by high-throughput data. Finally, we formed a TFs-mRNA-miRNA regulatory network diagram. Through the analysis above, we obtained four important immune cells. And the immune-related gene chip of the blood samples was analyzed to figure out the 36 significant DE-IRGs. Based on the operations above, we confirmed six immune-related hub genes involved in the pathogenesis of COVID-19 and analyzed their relationship with critical immune cells. Conclusions:It was concluded that TLR2, CAMP, S100A9, BCL6, CD4, and IL7R could be used as potential biomarkers to provide corresponding value for the diagnosis and the prognosis of COVID-19.