Sim G K, Augustin A
Basel Institute for Immunology, Switzerland.
J Immunol. 1991 Apr 1;146(7):2439-45.
Neither function nor Ag recognition properties of gamma delta T cells are well understood yet. A TCR gamma-chain family, characterized by distinct N region sequences that converge in coding for a "GxYS" VJ junctional sequence, appears late in ontogeny among highly diversified V gamma 4J gamma 1C gamma 1 chains of C57BL/6 and BALB/c mice. The glycine and serine codons are of germline V gamma 4 and J gamma 1 origin, respectively, whereas the N region consists of a variable amino acid residue x, followed by an invariant tyrosine Y. The high expression of V gamma 4 xYJ gamma 1C gamma 1 in the lung of BALB/c mice compared to that of C57BL/6 is apparently due to a novel pattern of strain-dependent positive selection which, unlike for alpha beta TCR, operates extrathymically. This type of selection seems to be determined by strain specific polymorphic ligands encoded outside of the classical H-2 region.
γδ T细胞的功能和抗原识别特性目前尚未完全明确。一个TCRγ链家族，其特征是具有独特的N区序列，这些序列在编码“GxYS”VJ连接序列时汇聚在一起，在C57BL/6和BALB/c小鼠高度多样化的Vγ4Jγ1Cγ1链的个体发育后期出现。甘氨酸和丝氨酸密码子分别来源于种系Vγ4和Jγ1，而N区由一个可变氨基酸残基x组成，后面跟着一个不变的酪氨酸Y。与C57BL/6小鼠相比，BALB/c小鼠肺中Vγ4xYJγ1Cγ1的高表达显然是由于一种新的菌株依赖性阳性选择模式，与αβ TCR不同，这种选择在胸腺外进行。这种选择类型似乎由经典H-2区域外编码的菌株特异性多态配体决定。
