Peptide Histidine Isoleucine (PHI) in the Respiratory Tract

(1)从大鼠PHI免疫家兔获得了与血管活性肠肽（VIP）不发生反应的高效价肽组氨酸异亮氨酸（PHI）抗血清，并用该抗血清建立了大鼠PHI放射免疫测定方法。采用微波辐照处死大鼠，解剖气管、肺外支气管和肺。用0.5 N醋酸匀浆，离心。冻干上清用作放射免疫测定的样品。PHI的免疫反应性主要发生在中央气道而非外周气道。大鼠呼吸道中VIP的免疫反应性与PHI的免疫反应性一样强，表明在大鼠呼吸道中，PHI和VIP可能是由同一前体以1:1的比例产生的。(2)静脉给药VIP或PHI可降低动态呼吸阻力；但效果明显低于异丙肾上腺素。VIP和P . More HI通过静脉给药组胺抑制动态呼吸阻力的增加，且呈剂量依赖性，提示VIP和PHI可能通过抑制介质释放对气道的影响参与气道高反应性的发病机制。(3) VIP对活化的外周血中性粒细胞、单核细胞和人单核细胞U937的超氧阴离子产生有剂量依赖性的抑制作用，其超氧阴离子的形成能力是通过干扰素γ预处理诱导的。VIP还能抑制支气管肺泡灌洗获得的活化的外周血嗜酸性粒细胞和肺泡巨噬细胞产生超氧阴离子，提示VIP可能是呼吸道炎症反应的内源性调节剂。(4)用大鼠PHI免疫家兔获得与VIP不发生反应的高效价PHI抗血清，用放射免疫法测定豚鼠呼吸道PHI样免疫反应性。对气管、肺外支气管和肺进行解剖，微波照射治疗。用0.5 N醋酸匀浆，离心。冻干上清用作放射免疫测定的样品。中心气道的PHI样免疫反应性高于外周气道。静脉给药白三烯C_4显著降低气管和肺外支气管的PHI样免疫反应性，同时显著增加动态呼吸阻力。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