Among the fewer than 10 proteins primarily secreted by the species Lactobacillus plantarum, there is one of 30 kDa that contains an internal fragment without cleavage sites for the most important intestinal proteases and characterized by having a serine and threonine content of at least 50%. The genetic information encoded in this fragment, designated ST peptide, has been used for producing and purifying said peptide, thus making it possible to conduct various tests in vitro. To summarize, the ST peptide is considered to promote the process of immunologic ignorance of our gastrointestinal immune system toward the commensal bacteria of our gastrointestinal tract, thus favoring the mechanisms of oral tolerance. Therefore the ST peptide could be used in immunotherapy, especially in the context of certain autoimmune diseases and certain inflammatory diseases.
