Comment on "Some Immunomodulatory Effects of Probiotic Bacteria Might Be Due to Porcine Neutrophil Elastase Inhibitor, a Serpin Present in MRS Broth" [Immunol. Lett. (December) (in Press) 1]

Serpins that are present in MRS broth were suspected to be responsible for some of the observed immunomodulatory effects of probiotic bacteria conditioned media. Some comments on this reporting, together with considerations dealing with manipulation of spent culture media and possible interfering effects, are discussed.