Long‐Residence Pneumonia Vaccine Developed Using PEG‐Grafted Hybrid Nanovesicles from Cell Membrane Fusion of Mycoplasma and IFN‐γ‐Primed Macrophages

Abstract CD8⁺ T cell responses play a critical regulatory role in protection against mycoplasma infection‐related respiratory diseases. Nanovesicles derived from cell membranes have been shown to induce CD8⁺ T cell responses. Moreover, the short residence time of mycoplasma membrane‐related vaccines in local lymph nodes limits the efficacy of current mycoplasma vaccines. Here, a long‐residence pneumonia vaccine is developed using nanovesicles prepared by cell membrane fusion of Mycoplasma hyopneumoniae and interferon‐γ (IFN‐γ )‐primed macrophages, which are grafted with polyethylene glycol to increase residence time in the lymph nodes. Upregulation of intercellular adhesion molecule‐1 (ICAM‐1) on the membrane of IFN‐γ‐primed macrophages increases the targeting of the hybrid nanovesicle vaccine to the local lymph nodes, with increased CD8⁺ T cell activation. A mechanistic study reveals that CD8⁺ T cell activation is achieved via a pathway involving upregulation of C‐C motif chemokine ligand 2/3 expression by E26 transformation‐specific sequences, followed by increased immune‐stimulatory activity of dendritic cells. In vivo, prophylactic testing reveals that the hybrid nanovesicle vaccine triggers a long‐term immune response, as evidenced by a memory CD8⁺ T cell response against mycoplasma infection. The current study provides a new design strategy for mycoplasma vaccines that involves a hybrid method using biological sources and artificial modification.