TICK INFESTATIONS ON CATTLE VACCINATED WITH EXTRACTS FROM THE EGGS AND THE GUT OF BOOPHILUS-MICROPLUS

Extracts prepared from the membranes of eggs (EM) and guts (GM) of Boo philus microplus were used to immunise cattle which were then infested twice with 20 000 larval ticks 1 week apart. EM antigens did not prot ect cattle against challenge with ticks, despite high levels of anti-e gg antibodies in the sera of the vaccinated cattle, detected by an ind irect enzyme-linked immunosorbent assay (ELISA). Cattle vaccinated wit h GM, however, had high levels of antibodies against GM and were prote cted significantly against challenge with B. microplus. Anti-EM and an ti-GM antibodies in the sera of cattle cross-reacted significantly wit h GM and EM respectively on ELISA and recognised both specific and com mon antigens in extracts of the eggs and guts of B. microplus on Weste rn blots. Exposure of cattle to field infestation with ticks during va ccination with gut antigens did not adversely affect the levels of ant ibodies generated.