B CELLS AND ACQUIRED T CELL IMMUNITY

我们最近发现补体(C)在迟发性超敏反应（DTH）和接触敏感性（CS）中的作用。这让我们发现了B细胞的作用。现在我们将研究涉及的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，IgM可能激活C，可能导致局部T细胞募集，特别是在致敏后早期（1-4天）。我们还将探索B-2细胞IgG2a和IgG2b c活化抗体，以及B细胞APC功能。明确目标1。识别所需的B细胞亚群。FACS纯化的正常B-1 vs B-2细胞将被转移到泛b细胞缺陷的JH-/-小鼠中。为了确定重组B细胞是否在诱导阶段起作用，我们还将免疫B细胞亚群转移到已经致敏的JH-/-小鼠中，然后刺激皮肤。也将使用表达优势B-1细胞和B-2细胞的辐射嵌合体。具体目标2。测定CS中B细胞的性质。如果B-1细胞优先参与，我们将确定它们是否是Thy-1+，这可能是通过激活的NK 1.1+细胞早期释放IL-4诱导的，激活的B-1细胞可能从腹膜迁移到淋巴结，并且可能具有不同的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。APC功能将在具有Ig+ B细胞但不分泌Ig的突变小鼠中进行研究。IgM的可能参与将通过使用缺乏分泌IgM的突变小鼠来确定。如果他们缺乏CS，我们将尝试用纯化的IgM单抗重组。更明确地说，我们将在相关特定Ig同型的JH-/-中创建转基因，以尝试cs重建。最后，我们将使用抗tnp IgM突变杂交瘤系来确定Fc部分的哪些氨基酸残基对DTH是必需的。在总结。我们的实验将确定参与DTH的B细胞亚群和Ig同型，以及B细胞是否在传入期和/或激发期起作用。假设B-1细胞的独特参与，作为B细胞参与的一部分。这些研究为抗体在诱导T细胞免疫中的作用提供了新的思路，并可能通过自然免疫（B-1细胞IgM）提供的联系将先天免疫(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，因此这些研究可能对深入了解T细胞疾病和免疫抵抗具有重要意义，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.