alloantibody
/əˈloʊ.əntɪˈbaɪ.ədi/Definitions
1. noun
An antibody produced in response to an antigen from a different individual of the same species, often resulting in a reaction when the two individuals are transfused with each other’s blood or when the two individuals mate.
“The doctor explained to the couple that their alloantibodies might cause complications in future pregnancies.”