Heterologous protection elicited by a live, attenuated, Leptospira vaccine

A previously-described live, attenuated vaccine (M1352, serovar Manilae, serogroup Pyrogenes) was tested in the hamster model of infection for cross-protective immunity. The vaccine elicited strong, significant cross-protection against lethal infection by strains representing four serologically distinct leptospiral serovars (Grippotyphosa, Australis, Canicola, and Autumnalis). Combined with our previously reported protection against serovars Pomona and Manilae, this work demonstrates unequivocal proof of concept for cross-protective immunity in leptospirosis.