English

guardee

From guard + -ee.

Formed from guard + -ee

Proto-Germanic *wardāną ‘to guard, protect’

…

Early Medieval Latin wardō

Old French guarder ‘to protect, guard’

Old French guarde ‘protection; guard’

Middle English garde ‘guardianship’

English guard

Today it means

noun Any protein (involved in an immune system) that when modified by a pathogen becomes bound by a guard protein, precipitating the immune response

Language periods are conventional ranges, not dates for this word.