Screening of Heat-killed Lactic Acid Bacteria with Food Allergy Alleviating Effects and Its Whole Genome Sequencing Analysis
Food allergy(FA)is an abnormal response of the human immune system to a specific food that causes dis-comfort in several systems,including the digestive,respiratory,skin and cardiovascular systems.In this study,heat-killed Lactobacillus paracasei JY56(HK-L.paracasei JY56)with strong anti-allergic activity was screened from 20 strains of lactic acid bacteria by hyaluronidase inhibition assay and RBL-2H3 cell assay.Subsequently,the safety of L.paracasei JY56 was evaluated by whole genome sequencing and in vitro safety assays.Finally,an ovalbumin(OVA)-in-duced FA mouse model was constructed to further clarify the effect of HK-L.paracasei JY56 on the alleviation of clini-cal symptoms in FA mice.The results showed that HK-L.paracasei JY56 had high β-aminohexosidase(β-HEX)inhibi-tion rate,and the levels of cytokines IL-4,IL-5,IL-13 and TNF-α were significantly reduced after its intervention.Whole genome sequencing analysis revealed that L.paracasei JY56 does not possess the ability to virulently and trans-mitly receive antibiotic resistance genes.The safety evaluation experiments such as antibiotic susceptibility test,hemolysis test and harmful metabolite evaluation revealed that L.paracasei JY56 was susceptible to commonly used antibiotics and did not produce hemolysis or harmful metabolites.OVA stimulation resulted in decreased body weight and rectal tempera-ture and increased allergy score in mice,while HK-L.paracasei JY56 intervention significantly alleviated allergy symp-toms in mice.In conclusion,this study provides a theoretical basis for the use of HK-L.paracasei JY56 for the allevia-tion of food allergy and related diseases.
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