CROSS-REACTIVITY BETWEEN HARD TICK ANTIGENS

1. The present study was carried out to determine the target cells and tissues for anti-tick immunoglobulins using an indirect immunohistoch emical technique. 2. Sections in triplicate prepared from unfed ticks Rhipicephalus appendiculatus, R. evertsi and Amblyomma variegatum were used to assess the cross-reactivity of serum from guineapigs naturall y infested with these tick species or immunized against them. 3. The s ections showed slight (+) to strong (++++) labelling of several struct ures in the tick body, e.g. salivary gland, gut lumen and malpighian t ubules, depending on the serum used. 4. The immune serum resulting fro m the immunization of guinea pigs with an extract of unfed nymphs of R . appendiculatus ticks showed the most intense cross-reactivity with t he sections examined.