Enhancement of CD8+ T Cells by the Type II Heat-Labile Enterotoxins LT-IIb and LT-IIc (Completed 2015)

The development of effective vaccines against infectious pathogens is one of modern medicine’s greatest achievements. However, most modern vaccines only elicit humoral responses and are unable to protect against diseases that require cellular immunity. Therefore, the development of vaccine strategies to produce both humoral and cellular immunity is of critical importance. Due to the lack of “danger signals” from modern subunit vaccines, adjuvants are required for robust cellular immune responses. The AB₅ heat-labile enterotoxin family (HLT) that includes cholera toxin (CT), and the heat-labile enterotoxins type I (LT-I) and type II (LT-II) are among the most potent adjuvants available. While CT and LT-I have been shown to be potent stimulators of predominantly humoral and Th2 T cell responses in most vaccine preparations, the LT-IIs uniquely exhibit a balanced Th1/Th2 enhancement and a distinct cytokine profile that promote both humoral and cellular immunity. Our focus is to elucidate the mechanisms that are responsible for the unique immunological properties of these potent adjuvants. 

Terry Connell, PhD