Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
immunogen is a noun meaning "any substance or organism that provokes an immune response (produces immunity) when introduced into the body". It carries one recorded sense.
any substance or organism that provokes an immune response (produces immunity) when introduced into the body
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for immunogen come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.