Characterization of Leptospira ballum strains isolated from clinical cases. Cross immunity in Hamsters vaccinated with vax-SPIRAL registered

In order to obtain L. ballum strains for the production of mono or polyvalent vaccines against human leptospirosis, 10 clinical strains isolated in Holguin, Cuba, were evaluated. They were classified by means of Microaglutination test (MAT) using polyclonal and monoclonal reference antibodies. Virulence, immunogenicity and potency were studied in Syrian Golden Hamster model. Humoral immune response was evaluated by MAT. Cross immunity between the serovar of L. ballum serogrup and the serovars canicola, copenhageni and mozdok, components of vax-SPIRAL registered , was define by means of the potency assay in vaccinated, hamsters, challenged with 10,000 DL sub(50) of virulent strains of the serovars above described, 21 days after the second dose. The results showed that 3 strains belonged to serogroup pomona serovar mozdok and 7 strains to serogroup ballum, belonging 2 to serovar arborea and 5 to serovar ballum. The virulence, immunogenicity and potency was demonstrated. The existence of cross protection was demonstrated. There was observed 100% of survival in vaccinated animals in respect with 80-100% of mortality in non vaccinated animals.