Macrolides have immunomodulatory effects that are beneficial for humans suffering from many inflammatory pulmonary diseases. These effects have been shown for tulathromycin, as reported in TULISSIN(R) Injection SPC below:
In addition to its antimicrobial properties, tulathromycin demonstrates immune-modulating and anti-inflammatory actions in experimental studies. In both bovine and porcine polymorphonuclear cells (PMNs; neutrophils), tulathromycin promotes apoptosis (programmed cell death) and the clearance of the apoptotic cells by macrophages. It lowers the production of the pro-inflammatory mediators leukotriene B4 and CXCL-8 and induces the production of anti-inflammatory and pro-resolving lipif lipoxin A4.
Particularly regarding swine respiratory disease complex, clearance of apoptotic cells by macrophages has been shown in vitro for Actinobacillus pleuropneumoniae and immunomodulatory effects seen in PRRSv infected porcine macrophages. It is important to mention that these immunomodulatory effects do not impair normal immune response. Such non antimicrobial effects of tulathromycin are potentially interesting to treat BRD and SRD.