STRUCTURE OF THE HUMAN MILK INHIBITOR OF HIV BINDING

我们已经发现，人乳抑制了人的GP 120的结合， 免疫缺陷病毒（HIV）包膜糖蛋白，CD 4，人 宿主细胞受体;这种结合被认为是必不可少的第一步 艾滋病病毒传染性的步骤。在牛血清中未发现抑制活性 牛奶也不存在于人类血清中，但其他一些物种的牛奶表现出 可变活动我们建议在纯化中纯化HIV抑制因子。 母乳，并精确定义其生化，免疫学， 生物物理特性初步生化和免疫学 研究表明，这种抑制性物质在其天然状态下是一种 大于250 Kd的大分子，等电点为9.3-9.6， 可能硫酸化和糖基化，但不含甘露糖， 唾液酸抑制剂的比活性至少为一个数量级， 其数量级大于硫酸葡聚糖，这意味着高度特异性的 强大的机制。活性因子与牛奶有关 大分子如糖蛋白、粘蛋白或糖胺聚糖。我们 最近发现，从人乳脂肪球中分离的粘蛋白复合物 膜阻断CD 4结合。将通过以下方法测定抑制活性： 样品抑制HIV包膜结合的能力 糖蛋白gp 120（或其单克隆抗体替代物，OKT 4A）对CD 4， 并抑制HIV在培养细胞中的复制。结构性 活性大分子的特征，与 将确定保护性活动。我们将开发一种固相 用于检测和测量活性因子的测定法， 寻找含有抑制剂的材料的替代来源 分子。因此，鉴定了一类新的化合物， 抗艾滋病毒治疗潜力是该项目的主要目标。的 研究还将为风险评估提供信息， 与围产期HIV感染相关的因素。 艾滋病毒的围产期传播正在迅速成为新的艾滋病毒感染的主要来源。 艾滋病病例。儿童艾滋病通常会导致无法茁壮成长，精神 迟钝和死亡虽然母乳中含有 免疫球蛋白和非免疫球蛋白因子抑制几种 微生物病原体，它也被称为作为代理的垂直 传播某些病毒。母乳被认为是 艾滋病毒传播媒介，引起人们对母乳喂养的关注， 艾滋病毒高发病率的人群;然而，大多数流行病学 有证据表明， 艾滋病毒感染母亲的人口垂直传播。因此，在本发明中， 确定一种在母乳中HIV传播的特异性抑制剂， 提供有助于制定公共卫生政策的信息， 除了其潜在的效用，为制定一个 具有低潜在的抗肿瘤活性的新的治疗或预防剂家族 宿主毒性

We have found that human milk inhibits the binding of gp120, the human immunodeficiency virus (HIV) envelope glycoprotein, to CD4, the human host cell receptor; this binding is thought to be an essential first step in HIV infectivity. The inhibitory activity was not found in bovine milk nor in human sera, but the milks of some other species exhibit variable activity. We propose to purify the HIV inhibitory factor(s) in human milk and to define precisely its biochemical, immunological, and biophysical characteristics. Preliminary biochemical and immunological studies indicate that this inhibitory material in its native state is a macromolecular larger than 250 Kd with an isoelectric point of 9.3-9.6, possibly sulfated and glycosylated, but containing neither mannose nor sialic acid. The specific activity of the inhibitor is at least an order of magnitude greater than dextran sulfate, implying a highly specific and potent mechanism. The active factor is associated with milk macromolecules such as glycoproteins, mucins or glycosaminoglycans. We recently found that a mucin complex isolated from human milk fat globule membrane blocks CD4 binding. Inhibitory activity will be determined by the ability of a sample to inhibit binding of the HIV envelope glycoprotein gp120 (or its monoclonal antibody surrogate, OKT4A) to CD4, and to inhibit the replication of HIV in cultured cells. The structural features of the active macromolecules that are associated with the protective activity will be determined. We will develop a solid phase assay for detection and measurement of the active factor in order to seek alternate sources of materials containing the inhibitory molecule(s). Thus the identification of a new class of compounds with anti-HIV therapeutic potential is the major goal of this project. The studies will also provide information for the assessment of the risk factors associated with perinatal HIV infection. Perinatal transmission of HIV is rapidly becoming a major source of new AIDS cases. Pediatric AIDS usually results in failure to thrive, mental retardation, and death. Although human milk is known to contain immunoglobulin and non-immunoglobulin factors that inhibit several microbial pathogens, it is also known to act as the agent of vertical transmission for certain viruses. Breast milk has been suggested as an agent of HIV transmission, raising concerns regarding breast feeding in populations with high incidence of HIV; however, most epidemiologic evidence indicates no breast-feeding-related increase in the rate of vertical transmission by populations of HIV infected mothers. Thus, defining a specific inhibitor of HIV transmission in human milk might contribute information useful in formulating public health policy, in addition to its potential utility for providing a basis for developing a novel family of therapeutic or prophylactic agents with low potential of host toxicity.