Echinacea purpurea polysaccharide reduces the latency rate in herpes simplex virus type-1 infections.

OBJECTIVE During the latency period of herpes simplex virus type-1 (HSV-1), the virus can occasionally reactivate, travel back to the eye and cause recurrent ocular disease. As this condition arises from the ability of HSV-1 to produce a dormant infection, effective medication to prevent the virus enter a latent state should prevent it. In this study, we applied Echinacea polysaccharide (EP) fraction as prophylactic mediator for latency prevention. METHODS In order to investigate the protective properties of EP, we evaluated its immunostimulatory functions on different immune aspects that play important roles in latency prevention (particularly IFN-gamma as one of the main indicators of cellular immunity and latency). Finally, we assessed establishment of latency by detection of thymidine kinase gene in trigeminal ganglia of BALB/c mice. RESULTS We demonstrated that EP promotes immune response, leading to a reduced latency rate, and it has a promising effect on latency prevention. CONCLUSION EP was able to exert an antiviral action on the development of recurrent HSV-1 disease when supplied prior to infection.