ɪfˈɛktɚz ɑːɹ pɹˈoʊtiːnz ɛŋkˈoʊdᵻd baɪ pˈæθədʒənz, wˌɪtʃ ˈækt tʊ ɪfˈɛkt ɐ ɹᵻspˈɑːns fɹʌm ɐ hˈoʊst sˈɛl ˈɔfən mˈɑːdʒuːlˌeɪɾɪŋ ðə hˈoʊst ɪmjˈuːn ɹᵻspˈɑːns.
Effectors are proteins encoded by pathogens, which act to effect a response from a host cell - often modulating the host immune response.