Nair T S, Raphael Y, Dolan D F, Parrett T J, Perlman L S, Brahmbhatt V R, Wang Y, Hou X, Ganjei G, Nuttall A L
Cell Biology Laboratory, Kresge Hearing Research Institute, University of Michigan, Ann Arbor 48109-0506, USA.
Hear Res. 1995 Mar;83(1-2):101-13. doi: 10.1016/0378-5955(94)00194-u.
Monoclonal antibodies KHRI-3 and KHRI-5 identify antigens expressed on inner ear supporting cells and auditory hair cells respectively. To determine if these antibodies affect inner ear function groups of syngeneic Balb/c mice were inoculated with hybridomas KHRI-3, KHRI-5 and other Ig-secreting hybridomas. Hybridomas UM-A9, UM-7F11, the non-secreting SP2/0 myeloma and mice with no hybridoma were used as controls. Animals were tested for auditory brainstem responses (ABR) for frequencies of 4, 8, 16 and 24 kHz, before the inoculation of the hybridomas and at intervals of 6 to 10 days thereafter or daily once tumors became palpable. In normal mice there were no changes in ABR thresholds over the course of the experiment. Other control animals showed little change in ABR even when the growth of the hybridoma or myeloma tumors were far advanced. Of the KHRI-5 hybridoma bearing animals only one of seven animals exhibited threshold shifts greater than 15 dB. In contrast, most mice bearing the KHRI-3 hybridoma exhibited high frequency threshold shifts of 40-50 dB that coincided temporally with the growth of the hybridoma, the presence of circulating KHRI-3 antibody, and greatly increased immunoglobulin titers. Ears from KHRI-3-bearing mice that developed high frequency hearing loss also had a novel type of lesion in the basal turn of the cochlea that was characterized by loss of outer hair cells and absence of typical supporting cell scars. Such changes were not found in control hybridoma-bearing mice. These findings suggest that KHRI-3 antibody has an effect on hearing that is secondary to damage to the organ of Corti and loss of outer hair cells. Our results have important implications for antibody-mediated mechanisms of hearing loss and provide an animal model in which to study this phenomenon.
单克隆抗体KHRI - 3和KHRI - 5分别识别内耳支持细胞和听觉毛细胞上表达的抗原。为了确定这些抗体是否影响内耳功能，将同基因的Balb/c小鼠分组，接种杂交瘤KHRI - 3、KHRI - 5和其他分泌免疫球蛋白的杂交瘤。杂交瘤UM - A9、UM - 7F11、不分泌的SP2/0骨髓瘤细胞以及未接种杂交瘤的小鼠用作对照。在接种杂交瘤之前以及之后每隔6至10天或一旦肿瘤可触及就每天检测动物在4、8、16和24 kHz频率下的听觉脑干反应（ABR）。在正常小鼠中，实验过程中ABR阈值没有变化。其他对照动物即使在杂交瘤或骨髓瘤肿瘤生长到晚期时ABR变化也很小。在接种KHRI - 5杂交瘤的动物中，7只动物中只有1只表现出阈值变化大于15 dB。相比之下，大多数接种KHRI - 3杂交瘤的小鼠表现出40 - 50 dB的高频阈值变化，这与杂交瘤的生长、循环中KHRI - 3抗体的存在以及免疫球蛋白滴度的大幅增加在时间上相吻合。出现高频听力损失的接种KHRI - 3的小鼠的耳朵在耳蜗基底转也有一种新型病变，其特征是外毛细胞缺失且没有典型的支持细胞瘢痕。在接种对照杂交瘤的小鼠中未发现此类变化。这些发现表明，KHRI - 3抗体对听力的影响是继发于柯蒂氏器损伤和外毛细胞丧失的。我们的结果对抗体介导的听力损失机制具有重要意义，并提供了一个研究这一现象的动物模型。
