Oxidative stress, excessive production of reactive oxygen species, is considered an important part of different disorders, as well as of physiological processes (inflammation). The difference between physiological and pathological oxidative stress is often the occurrence of lipid peroxidation and its final toxic products, among which is 4-hydroxy-2-nonenal (HNE), a reactive aldehyde that forms protein conjugates. The aim of this study was to determine the distribution of HNE-histidine conjugates in leukocytes during systemic inflammation. We used genuine monoclonal antibodies against HNE-histidine conjugates for immuno-cytochemical, immuno- histochemical and immuno-electronmicroscopical analyses of HNE in inflammatory cells. Spleen tissue, leukocytes from blood and macrophages from the peritoneum of rats intraperitoneally (i.p.) injected with micronized zeolite (MZ) were analyzed. HNE-histidine conjugates were predominantly detected near cell membranes, phagosomes and macrophage granules. Immunodetection of HNE-histidine conjugates may be used as an analytical immunochemical method to study HNE formation in pathological and physiological processes and for pathomorphological diagnostic procedures.Oksidacijski stres, stanje prekomjernoga stvaranja reaktivnih kisikovih tvari, bitna je sastavnica različitih bolesti, ali i fizioloških procesa (upala). Često je razlika između fiziološkoga i patološkoga oksidacijskoga stresa pojava lipidne peroksidacije i njenih završnih toksičnih produkata, među kojima posebnu ulogu ima 4-hidroksi- 2-nonenal (HNE), reaktivni aldehid koji tvori konjugate s bjelančevinama. Cilj ovoga istraživanja bio je utvrditi distribuciju HNE-histidinskih konjugata u leukocitima tijekom nespecifične upalne reakcije. Rabili smo izvorna monoklonalna protutijela na HNE-histidinski konjugat, za imuno-citokemijsko, histokemijsko i elektronskomikroskopsko dokazivanje HNE-a u upalnim stanicama. Analizirano je tkivo slezene, leukociti iz krvi te makrofazi štakora kojima je intraperitonealno injiciran mikronizirani zeolit (MZ). HNE-histidinski konjugati pretežito su uočeni uz stanične membrane te pored fagosoma i makrofagnih granula. Imunodetekcija HNE-histidinskih konjugata mogla bi se stoga rabiti kao analitička imunokemijska metoda za istraživanja fizioloških i patoloških procesa te u patomorfološkim dijagnostičkim postupcima
