A SECRETED CALRETICULIN PROTEIN IN IXODID TICK (AMBLYOMMA-AMERICANUM)SALIVA

A complementary DNA clone from salivary glands of feeding female Ambly omma americanum ticks has been characterized as encoding calreticulin. Calreticulin, a major endoplasmic reticulum (ER) calcium-binding prot ein, appears to be secreted in Amblyomma and Dermacentor saliva. Evide nce is accummulating that calreticulin performs roles unrelated to cal cium storage, Unlike most known calreticulins, tick-secreted calreticu lin lacks the ER retention signal, KDEL. This is the first molecular c loning of a specific tick salivary gland protein. The finding of a sec reted calreticulin in tick saliva suggests a role for calreticulin in blood feeding through host immunosuppression or antihemostasis.