B CELLS AND ACQUIRED T CELL IMMUNITY

我们最近发现补体 (C) 在迟发型超敏反应 (DTH) 和接触敏感性 (CS) 中发挥作用。这导致我们发现了 B 细胞的作用。现在我们将研究所涉及的 B 细胞亚群和 Ig 同种型。 B-1 B 细胞亚群可能通过分泌 IgM 发挥作用，这可能会激活 C，可能导致局部 T 细胞募集，特别是在致敏后的早期（1-4 天）。我们还将探索 B-2 细胞 IgG2a 和 IgG2b C 激活抗体以及 B 细胞 APC 功能。具体目标#1。鉴定所需的 B 细胞亚群。将 FACS 纯化的正常 B-1 与 B-2 细胞转移至泛 B 细胞缺陷型 JH-/- 小鼠中。为了确定重建的 B 细胞是否在诱导阶段发挥作用，我们还将将免疫 B 细胞亚群转移到已经致敏的 JH-/- 小鼠中，然后挑战皮肤。也将使用表达显性 B-1 与 B-2 细胞的放射嵌合体。具体目标#2。确定 CS 中 B 细胞的特性。如果优先涉及 B-1 细胞，我们将确定它们是否是 Thy-1，这可能是通过活化的 NK 1.1 细胞早期释放 IL-4 诱导的，活化的 B-1 细胞可能从腹膜迁移到淋巴结，并可能具有多样化的 V 区和更高的 Ag 亲和力。具体目标#3。确定 B 细胞在 CS 中的功能。将在具有 Ig B 细胞但不分泌 Ig 的突变小鼠中探索 APC 功能。 IgM 的可能参与将通过使用仅缺乏分泌的 IgM 的突变小鼠来确定。如果它们缺乏 CS，我们将尝试用纯化的 IgM mAb 进行重构。更明确地说，我们将在相关特定 Ig 同种型的 JH-/- 中创建转基因，以尝试 CS 重建。最后，我们将使用抗 TNP IgM 突变杂交瘤系，以确定 Fc 部分中的哪些氨基酸残基对于 DTH 至关重要。总之。我们的实验将确定参与 DTH 的 B 细胞亚群和 Ig 同种型，以及 B 细胞是否在传入和/或引发阶段起作用。假设 B-1 细胞独特参与，作为 B 细胞参与的一部分。这些研究带来了关于抗体在引发 T 细胞免疫方面发挥作用的新想法，并且可能通过自然免疫（B-1 细胞 IgM）提供的连接，将先天免疫 (C) 与获得性 T 细胞免疫 (DTH) 独特地联系起来。由于 DTH 是体内 T 细胞反应的核心，这些研究对于深入了解 T 细胞疾病和免疫抵抗可能很重要，因此可能对人类健康具有广泛的适用性。

We recently found a role for complement (C) in delayed-type hypersensitivity (DTH), and in contact sensitivity (CS). This led to our finding a role for B cells. Now we will investigate B cell subsets and Ig isotypes that are involved. The B-1 B cell subset likely plays a role by secreting IgM, that may activate C, possibly leading to local T cell recruitment, especially early after sensitization (1-4 days). We also will explore B-2 cell IgG2a and IgG2b C-activating antibodies, and B cell APC function. SPECIFIC AIM #1. To identify needed B cell subsets. FACS purified normal B-1 vs B-2 cells will be transferred into pan B-cell deficient JH-/- mice. To determine if reconstituting B cells act at the elicitation phase, we also will transfer immune B cell subsets into already sensitized JH-/- mice, and then challenge the skin. Radiation chimeras that express dominant B-1 vs B-2 cells, also will be used. SPECIFIC AIM #2. Determine properties of B cells in CS. If B-1 cells are preferentially involved, we will determine if they are Thy-1+, that may be induced via an early release of IL-4 from activated NK 1.1+ cells, and activated B-1 cells may possibly migrate from peritoneum to lymph nodes, and potentially have diverse V regions, and higher Ag affinity. SPECIFIC AIM #3. Determine how B cells function in CS. APC function will be explored in mutant mice with Ig+ B cells, but no secreted Ig. The possible involvement of IgM will be determined by employing mutant mice that just lack secreted IgM. If they are deficient in CS, we will attempt reconstitution with purified IgM mAb. More definitively, we will create transgenes in JH-/- of relevant specific Ig isotypes, to attempt CS-reconstitution. Finally, we will use anti-TNP IgM mutant hybridoma lines, to determine which amino acid residues in the Fc portion are essential for DTH. IN SUMMARY. Our experiments will determine the B cell subset(s) and Ig isotype(s) involved in DTH, and whether B cells act in the afferent, and/or the elicitation phase. Unique participation of B-1 cells is postulated, as one part of B cell involvement. These studies bring new ideas about antibodies acting in eliciting T cell immunity, and may uniquely connect innate immunity (C), with acquired T cell immunity (DTH), via linkage provided by natural immunity (B-1 cell IgM). Since DTH is central to in vivo T cell reactivity, these studies may be important to an indepth understanding of T cell diseases and immune resistance, and thus may have wide applicability to human health.