PROBIOTIC BIFIDOBACTERIA IN THE MANAGEMENT OF COVID-19 Hüseyin S. Bozkurt Correspondence Author: Huseyin Sancar Bozkurt.Maltepe University,Internal Medicine,Clinic of Gastroenterology.e-mail:email@example.com.Phone: 00905054482291 ORCID number:0000-0003-2097-2950 Conflict of Interest: The author declare no any financial dislosure Abstract: COVID-19 is a pandemic virus that manifests itself with respiratory distress as well as leading to symptoms and signs associated with the gastrointestinal tract. Possible therapeutic and protective effects of probiotic bacteria on the immunological mechanisms of action in the gastrointestinal system may be important for development of future treatment and preventive vaccine modalities. Introduction: COVID-19 is a new cause of outbreak that can affect lungs and airways. It's caused by a virus called coronavirus. Since the physiological mechanism of the virus has not been resolved completely, uncertainties about treatment remain. The effect of the virus on the gastrointestinal system besides the lung system shows that immunological processes are important in illness. A new treatment approach model can be promising with the probiotic bacteria by immune modulation. Methods: Autophagy is the cell's self-destruction process. It is a process that begins with the endoplasmic reticulum (ER) under stress and ends with the destruction of the destructive metabolites in the cell and cell nucleus, which are collected in autophagosomes. While the process caused by stresses such as osmotic and salt roughly causes autophagy via the Target of Rapamycin(TOR) kinase pathway , oxidative and ER stress conditions lead to autophagy via the inositol-requiring enzyme 1 (IRE1) pathway . Certain foods that cause ER stress and infections (such as ınfluenza,coronavirus) increase the inflammation cascade and viral replication by accelerating this autophagy process. Also,vırus replication has been shown to decrease by blocking IRE1 pathway . Results: Interleukin -17( mainly from IL-17-producing T cells) is a pro-inflammatory and procarcinogenic cytokine that plays an important role on the adaptive immune system . IL-17 is also a very strong inducer of ER stress and autophagy via IRE1 . With the IL-17 blockade, ER stress-related autophagy and inflammation have been prevented . IL-17 also plays an important role in inflammatory bowel diseases . Since the relationship between coronavirus and the gastrointestinal tract has been clearly shown , this effect is highly likely to show through IL-17. Discussion: Some strains of Bifidobacterium have IL-17 inhibitory effect .Theoretically, A high-single dose administration of appropriate and reliable Bifidobacterium strain (eg BB-12, Infantis) or use of these strains’ lipopolysaccharide membranes in vaccine development especially in patients with gastrointestinal symptoms (diarrhea, abdomen pain, vomiting) can be considered as a therapeutic and preventive method in Coronavirus ınfected patients .Bifidobacterium animalis is highly likely to prevent the replication of coronavıruses by reducing ER stress-related autophagy over the anti interleukin-17 effect . Also, probiotic Bifidobacteria species could be considered in current vaccine models as natural adjuvants Conclusion: Since the relationship between viral replication and gastrointestinal immunity is very close, an effective approach over probiotic bacteria can play an important role in stopping viral replication. New approaches to the single strain probiotic bacteria can be promising, both in terms of vaccination and treatment models.