OVINE LEPTOSPIROSIS - IMMUNE-RESPONSE TO EXPERIMENTAL-INFECTION

The humoral and cell-mediated immune (CMI) response to experimental in oculation of lambs with leptospiral serovars, viz. Leptospira pomona, Leptospira grippotyphosa and Leptospira icterohaemorrhagiae, were stud ied. The antibody response was assessed by microscopic agglutination t est (MAT) and enzyme-linked immunosorbent assay (ELISA). The CMI respo nse was assessed by leukocyte migration inhibition test (LMIT). All th e lambs evoked a detectable response by MAT on the day 7 post -inocula tion (DPI) and a significant response on 14 DPI. The response was maxi mum during 28-35 DPI, with variation in titre between serovars. In ELI SA, significant titre was observed on 7 DPI with a peak titre recorded on 14 DPI followed by a decline in titre, with variation in titre bet ween serovars. The CMI response was observed on 7 DPI, peaked on 14 DP I with difference in mean percentage of inhibition of leukocyte migrat ion between serovars, and declined to a lower level by 35 DPI.