Identification of leptospiral antigens recognized by gamma/delta T cells as target for development of next generation vaccines

Abstract

Leptospirosis is a systemic disease caused by pathogenic bacteria of the genus Leptospira. The disease is considered a worldwide zoonosis and a major public health problem, and thus, the development of a vaccine is critical. Cuba, France and China have licensed vaccines for humans, but these formulations are based on inactivated leptospires, presenting a series drawback, such as serovar-dependence and T-independent immune response. Advances in the recombinant DNA technology and genome sequences have contributed to the identification of vaccine candidates. However, attempts at developing recombinant proteins or peptides-based vaccines to stimulate conventional alpha/beta T cell to provide cellular immune responses, have been mostly unsuccessful. Activation of nonconventional T cells such as gamma/delta T cells emerges as an alternative, since it has been shown that both human and bovine gamma/delta T cells are able to proliferate and produce IFN-gamma in response to Leptospira. WC1 molecules located on the surface of gamma/delta T seems act as gamma/delta TCR coreceptor and pattern recognition receptors interacting directly with bacterial components. However, the leptospiral component involved in this interaction is unknown. The investigation of antigens that may be recognized by gamma/delta T cells is fundamental for development of next generation vaccines. We believe that due to the expertise of Dr. Baldwin in this area, a significant contribution will be achieved in the field of Leptospira and leptospirosis. (AU)