Peptide Histidine Isoleucine (PHI) in the Respiratory Tract

(1)从大鼠组氨酸异亮氨酸(PHI)免疫的兔体内获得了不与血管活性肠肽(VIP)反应的高滴度PHI抗血清，并建立了大鼠PHI放射免疫分析方法。微波照射后处死大鼠，解剖气管、肺外支气管壁和肺组织。用0.5N醋酸匀浆，离心。以冻干上清液为样品进行放射免疫分析。PHI免疫反应多见于中央气道，外周气道较少。用商品化的VIP抗血清同时测定大鼠呼吸道VIP免疫反应的结果与PHI一样强，提示大鼠呼吸道VIP和VIP可能以1：1的比例产生。(2)静脉注射VIP或PHI可降低动态呼吸阻力，但作用明显小于异丙肾上腺素。贵宾和P…More HI以剂量依赖的方式抑制组胺静脉注射所致的动态呼吸阻力的增加，提示VIP和PHI可能通过抑制介质释放对气道高反应性的影响而参与了气道高反应性的发病。(3)VIP以剂量依赖的方式抑制外周血中性粒细胞、单核细胞以及人单核细胞系U937细胞产生超氧阴离子，而人单核细胞系U937产生超氧阴离子的能力是通过预先给予干扰素-γ诱导的。3x10；-6&gt；M VIP还能抑制经支气管肺泡灌洗后活化的外周血嗜酸性粒细胞和肺泡巨噬细胞产生的超氧阴离子，提示VIP可能是呼吸道炎症反应的内源性调节因子。(4)用大鼠PHI免疫兔获得高滴度的PHI抗血清，用放射免疫法检测豚鼠呼吸道的PHI免疫反应。分离气管、肺外支气管壁和肺组织，用微波照射治疗。用0.5N冰醋酸匀浆，离心。以冻干上清液为样品进行放射免疫分析。PHI样免疫反应在中央气道较外周气道多见。静脉注射白三烯C4可显著降低气管和肺外支气管内PHI样免疫反应，同时显著增加动态呼吸阻力。较少

(1) A high titer of peptide histidine isoleucine (PHI) antiserum which did not react with vasoactive intestinal peptide (VIP) was obtained from a rabbit immunized with rat PHI and rat PHI radioimmunoassay was established with this antiserum. Tracheas, extrapulmonary bronchi and lungs were dissected from rats sacrificed by microwave irradiation. They were homoginized with 0.5 N acetic acid and centrifuged. Lyophilized supernates were used as samples for the radioimmunoassay. PHI immunoreactivity occurred more in the central airways than in the peripheral ones. VIP immunoreactivity in rat respiratory tracts, assayed simultaneously by radioimmunoassay using commercialized VIPantiserum, was as strong as that of PHI, suggesting that PHI and VIP may be produced from the same precursor at the ratio of 1:1 in rat respiratory tracts.(2) Intravenous administration of VIP or PHI reduced dynamic respiratory resistance; however, the effect was significantly less than that of isoprenaline. VIP and P … More HI inhibited the increase in dynamic respiratory resistance by intravenous administration of histamine in a dose-dependent manner, suggesting that VIP and PHI may be involved in the pathogenesis of airway hyperresponsiveness through inhibiting the effect of mediator release on the airway.(3) VIP inhibited superoxide anion production in a dose- dependent manner by the activated peripheral blood neutrophils, mononuclear cells and also by the human monoblast cell line U937, the capacity of which for superoxide anion formation was induced by the pretreatment of interferon-gamma. 3x10^<-6> M VIP also inhibited superoxide anion generation by the activated peripheral blood eosinophils and alveolar macrophages obtained by bronchoalveolar lavage, suggesting VIP may serve as an endogenous modulator of inflammatory reactions in the respiratory tract.(4) A high titer of PHI antiserum which did not react with VIP was obtained from a rabbit immunized with rat PHI and PHI like immunoreactivity in the respiratory tract from guinea pigs was measured by radioimmunoassay. Tracheas, extrapulmonary bronchi and lungs were dissected and treated by microwave irradiation. They were homogenized with 0.5 N acetic acid and centrifuged. Lyophilized supernates were used as samples for the radioimmunoassay. PHI like immunoreactivity was present more in the central airways than in the peripheral ones. Intravenous administration of leukotriene C_4 reduced significantly PHI like immunoreactivity in the tracheas and the extrapulmonary bronchi in parallel with the significant increase of dynamic respiratory resistance. Less