THE INFLUENCE OF HEAVY-METAL EMISSIONS AND FASCIOLA-HEPATICA INFESTATION ON THE IMMUNOGENICITY OF A LISTERIA VACCINE

The effect of oral dosing with emissions containing heavy metals (mecu ry, lead, copper, cadmium, zinc and chromium) on immune status was tes ted in 3 groups of sheep. Two groups (Groups I and II) were given emis sions for 15 d. One of these groups (Group I) was then also infested w ith Fasciola hepatica metacercaria on day 16. These 2 groups (Groups I and II) and a control group (Group C) were immunized with a Listeria vaccine on days 8 and 22. A decreased index of metabolic response (IMR ) of phagocytes and reduced responses of lymphocytes to mitogenic acti vation with phytohemagglutinin and L monocytogenes antigen stimulation in the leukocyte migration-inhibition test were recorded. Decreased a gglutination titers of serum antibodies against L monocytogenes were o bserved. The F hepatica infestation had no significant effect on the m igration index or IMR.