Enhancement of lymphocyte blastogenesis and neutrophil function by avridine in dexamethasone-treated and nontreated cattle

Open Access
Publisher Website
Google Scholar
Abstract
SUMMARY: The lipoidal amine, N, N-dioctadecyl-N′, N′-bis (2-hydroxyethyl) propanediamine (avridine or CP 20,961), formulated in liposomes, was evaluated for its effect on leukocyte kinetics, lymphocyte blastogenesis, and polymorphonuclear leukocyte (pmn) function in dexamethasone-treated and nontreated cattle. In the 1st experiment, cattle were given avridine in a single im injection of 0.1, 1.0, or 10 mg/kg of body weight. All doses induced swelling at the injection site, a febrile response, and a leukocytosis due to a neutrophilia. Mononuclear cell numbers were normal. All 3 groups of avridine-treated animals had a higher mean lymphocyte blastogenic response to mitogens on the 4 days after administration than did the control nontreated animals. Avridine administration was associated with an enhanced ability of pmn to ingest Staphylococcus aureus and to mediate antibody-dependent cell-mediated cytotoxicity (adcc). The highest dose (10 mg/kg) was associated with a depression of the ability of pmn to iodinate protein. An effect of avridine on pmn random migration under agarose or nitroblue tetrazolium (nbt) reduction was not observed. In a 2nd experiment, cattle were given no treatment, 0.04 mg of dexamethasone/kg im, or 10 mg of avridine/kg im followed 24 hours later by 0.04 mg of dexamethasone/kg. Dexamethasone administration caused a leukocytosis due to a neutrophilia with normal mononuclear cell numbers, an enhancement of pmn random migration under agarose, and an inhibition of nbt reduction, iodination, and adcc activity of pmn. Dexamethasone did not have a detectable effect on lymphocyte blastogenesis or on ingestion of S aureus by pmn. Cattle that were given dexamethasone 24 hours after avridine had a prolonged leukocytosis due to a neutrophilia, which was gradually replaced by a marked increase in mononuclear cell numbers. An increase in mononuclear cells was not observed with either drug alone, Dexamethasone administration did not prevent the enhancement of lymphocyte blastogenesis or prevent pmn S aureus ingestion induced by avridine. Administration of avridine 24 hours before dexamethasone prevented the effects of dexamethasone on pmn random migration, nbt reduction, and adcc activity. Avridine did not prevent the dexamethasone-induced depression of pmn iodination.