ERYTHROPOIESIS BY CELL SURFACE COMPONENTS

而促生长对红系爆发性增殖的调节作用 人淋巴细胞条件培养液中的因素很好 有案可查的，我们对这些因素 运营是有限的。我们最近发现水泡是自发形成的 淋巴细胞的脱落以及纯化的淋巴细胞膜 含有大量的促猝发活性(BPA)，并具有 提供了初步结果，表明该活动驻留在 淋巴细胞膜的表面成分。这项提案的重点是 (1)促爆破活性(BPA)的纯化。我们 建议从血浆中提纯含有双酚A的蛋白质或糖蛋白 人类淋巴细胞膜，或来自自 培养中的淋巴细胞。我们将用非离子处理淋巴细胞膜 用于提取完整膜蛋白的洗涤剂以及高或 低盐介质，用于提取外周或吸附的蛋白质。这些提取物 将在培养中检测双酚A，并在适当的情况下进一步纯化 通过各种技术，包括亲和层析 凝集素亲和层析柱、蔗糖梯度离心柱及柱层析 层析法。(2)膜缔合和可溶性的交叉反应性 双酚A。我们将检验统一的假设，即可溶形式的双酚A 从膜结合的双酚A通过脱落或蛋白分解而得 正在处理。淋巴细胞质膜抗体，LCM来源 囊泡或部分纯化的膜BPA将被用来吸附或 中和高速液晶上清液中的可溶性双酚A。这个 交叉反应的演示将极大地促进我们对 双酚A的来源不仅来自淋巴细胞，而且可能来自其他细胞 也是。(3)双酚A的细胞来源和靶细胞的鉴定。我们 膜相关双酚A起源细胞(S)的鉴定 选择性地检测淋巴细胞制备的细胞膜或LCM 通过多种细胞吸附富集特定亚群(S) 技巧。使用类似的方法，我们将尝试确定 淋巴细胞膜和泡相关双酚A靶细胞(S)的检测 在骨髓和外周血单核细胞培养中 选择性地耗尽特定类型的细胞。

While the regulation of erythroid burst proliferation by growth promoting factors in culture media conditioned by human lymphocytes is well documented, our understanding of the mechanisms by which such factors operate is limited. We have recently shown that vesicles spontaneously shed from lymphocytes as well as purified lymphocyte plasma membranes contain significant amounts of burst promoting activity (BPA) and have provided preliminary results suggesting that this activity resides in surface components of lymphocyte membranes. The focus of this proposal is the following: (1) Purification of burst promoting activity (BPA). We propose to purify proteins or glycoproteins containing BPA from plasma membranes of human lymphocytes, or from vesicles shed spontaneously from lymphocytes in culture. We will treat lymphocyte membranes with nonionic detergents to extract integral membrane proteins as well as with high or low salt media to extract peripheral or adsorbed proteins. These extracts will be assayed in culture for BPA, and where appropriate further purified by a variety of techniques including affinity chromatography on lectin-affinity columns, sucrose gradient centrifugation and column chromatography. (2) Cross-reactivity of membrane-associated and soluble BPA. We will test the unifying hypothesis that soluble forms of BPA are derived from membrane associated BPA by shedding or proteolytic processing. Antibodies to lymphocyte plasma membranes, LCM derived vesicles or partially purified membrane BPA will be used to adsorb or neutralize soluble BPA contained in high speed LCM supernatants. The demonstration of cross reactivity would greatly advance our understanding of the source of BPA not only frm lymphocytes but possibly from other cells as well. (3) Identification of cell source and target cells of BPA. We propose to identify the cell(s) of origin of membrane-associated BPA by testing plasma membranes or LCM prepared from lymphocytes selectively enriched in particular subset(s) by a variety of cell adsorption techniques. Using similar methodology, we will attempt to identify the target cell(s) of lymphocyte membrane and vesicle-associated BPA by testing them in cultures of bone marrow and peripheral blood mononuclear cells which are selectively depleted of specific cell types.