Membrane Vesicles from <em>Lactobacillus acidophilus</em> Promote Superior Cytokine Modulation and Antimicrobial Signaling in RAW 264.7 Macrophages Compared with Whole Cells

The interaction between probiotic bacteria and the innate immune system is of in-creasing interest due to its capacity to modulate inflammatory and antimicrobial re-sponses. The murine macrophage cell line RAW 264.7 is widely used to investigate the immunomodulatory effects of probiotic bacteria and their cell-free derivatives, such as membrane vesicles (MVs). In this study, we evaluated whether MVs derived from Lactobacillus acidophilus promote superior modulation of cytokine production and antimicrobial signaling in RAW 264.7 macrophages compared with whole cells (W.C). Our results show that L. acidophilus MVs exhibited direct bactericidal activity against Escherichia coli and induced a more selective and balanced cytokine profile than whole cells. These findings highlight the potential of probiotic-derived membrane vesicles as acellular immunomodulatory effectors for the development of novel cell-free biotherapeutic strategies.