Mansikka A, Sandberg M, Veromaa T, Vainio O, Granfors K, Toivanen P
Department of Medical Microbiology, Turku University, Finland.
J Immunol. 1989 Mar 15;142(6):1826-33.
We have characterized maturation of B lymphocytes in the chicken Harderian gland. Expression of Ig genes was studied by using lambda L and mu H chain-specific DNA probes. In unstimulated chickens, the concentration of mu H chain and lambda L chain mRNA in the Harderian gland was observed to be greater than 8 times higher than in the bursa of Fabricius or spleen. By using in situ hybridization, the plasma cells expressing mu mRNA were located in central area of the gland packed around the tubules. Antibodies produced by the Harderian plasma cells were measured from the tears before and after antigenic stimulation. In unstimulated chickens high levels of total IgM, IgA, and IgG were observed. After ocular stimulation with tetanus toxoid, specific antitetanus IgG and IgA antibodies appeared in the tears but IgM antibodies were barely detectable. These results indicate that after antigenic stimulation the Harderian B cells rapidly mature through IgM secretion to the production of IgG or IgA. Southern blot analysis of the Harderian total genomic DNA showed strong rearrangement in the lambda L chain locus. In contrast, the band indicating major rearrangement in the mu H chain locus gave a very poor hybridization signal, indicating deletion of C mu genes in the Harderian gland DNA. As a conclusion, our present data indicate for the Harderian gland a role in terminal B cell differentiation and Ig class switch.
我们已对鸡哈德氏腺中B淋巴细胞的成熟过程进行了特征描述。通过使用λL和μH链特异性DNA探针研究了Ig基因的表达。在未受刺激的鸡中，观察到哈德氏腺中μH链和λL链mRNA的浓度比法氏囊或脾脏中的浓度高出8倍以上。通过原位杂交，表达μmRNA的浆细胞位于围绕小管堆积的腺体中央区域。在抗原刺激前后，从眼泪中测量哈德氏浆细胞产生的抗体。在未受刺激的鸡中，观察到高水平的总IgM、IgA和IgG。在用破伤风类毒素进行眼部刺激后，眼泪中出现了特异性抗破伤风IgG和IgA抗体，但几乎检测不到IgM抗体。这些结果表明，抗原刺激后，哈德氏B细胞通过分泌IgM迅速成熟，进而产生IgG或IgA。对哈德氏腺总基因组DNA的Southern印迹分析显示，λL链基因座发生了强烈重排。相比之下，表明μH链基因座主要重排的条带给出的杂交信号非常弱，表明哈德氏腺DNA中Cμ基因缺失。总之，我们目前的数据表明哈德氏腺在B细胞终末分化和Ig类别转换中起作用。
