Macrophage effector responses of horses are influenced by expression of CD154

• PMA/ionomycin stimulated foal PBMC produce less superoxide than adult PBMC.
• We cloned equine CD154 and stably expressed it in Chinese Hamster Ovary cells.
• Ectopically expressed reqCD154 elicits robust production of superoxide in MDM.
• Levels of CD154 expression may impact susceptibility to intracellular infections.

Reactive intermediates contribute to innate immunity by providing phagocytes with a mechanism of defense against bacteria, viruses and parasites. To better characterize the role of CD154 in the production of reactive intermediates, we cloned and expressed recombinant equine CD154 (reqCD154) in Chinese Hamster Ovary (CHO). In co-culture experiments, CHO cells ectopically expressing reqCD154 elicited superoxide production in monocyte-derived macrophages (MDM). Collectively, our results indicate that regulation of CD154 expression plays a role in innate host defenses.