Correct spelling for the English word "proteil" is [pɹˈə͡ʊtɪl], [pɹˈəʊtɪl], [p_ɹ_ˈəʊ_t_ɪ_l] (IPA phonetic alphabet).
An animal protein prepared for use as a therapeutic antigen.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.