The spelling of the word "immunisin" may seem strange, but it actually follows the rules of English phonetics. The first syllable "im-" is pronounced with a short "i" sound as in "it", followed by the "m" consonant. The second syllable "-mu-" has a long "u" sound as in "moon" and is followed by the "n" consonant. The final syllable "-sin" has a short "i" sound followed by the "s" and "n" consonant sounds. Overall, the word is pronounced as ih-myoo-nuh-sin.
Immune body, amboceptor.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.