Find in Library

The present study evaluated the avian macrophage responses against <i>Clostridium perfringens</i> that varied in their ability to cause necrotic enteritis in chickens. Strains CP5 (avirulent-<i>netB</i>+), CP1 (virulent-<i>netB</i>+), and CP26 (highly virulent-<i>netB</i>+<i>tpeL</i>+) were used to evaluate their effect on macrophages (MQ-NCSU cells) and primary splenic and cecal tonsil mononuclear cells. The bacilli (whole cells) or their secretory products from all three strains induced a significant increase in the macrophage transcription of Toll-like receptor (TLR)21, TLR2, interleukin (IL)-1β, inducible nitric oxide synthase (iNOS), and CD80 genes as well as their nitric oxide (NO) production and major histocompatibility complex (MHC)-II surface expression compared to an unstimulated control. The CP1 and CP26-induced expression of interferon (IFN)γ, IL-6, CD40 genes, MHC-II upregulation, and NO production was significantly higher than that of CP5 and control groups. Furthermore, splenocytes and cecal tonsillocytes stimulated with bacilli or secretory products from all the strains showed a significant increase in the frequency of macrophages, their surface expression of MHC-II and NO production, while CP26-induced responses were significantly higher for the rest of the groups. In summary, macrophage interaction with <i>C. perfringens</i> can lead to cellular activation and, the ability of this pathogen to induce macrophage responses may depend on its level of virulence.