Press J L, Giorgetti C A
J Immunol. 1986 Aug 1;137(3):784-90.
The splenic focus assay was used to clone B cells from neonatal, adult and xid mice in order to examine their primary and secondary responses to (T,G)-A--L. Adult precursor cell frequencies to (T,G)-A--L were achieved late in neonatal ontogeny. Primary xid B cells responded to DNP-HY but not to (T,G)-A--L in the splenic focus assay. The frequency of secondary B cells from (T,G)-A--L-primed xid mice was less than or equal to 10% that of secondary B cells from wild-type (non-xid or X/Xxid heterozygous) mice. Although xid B cells were poorly responsive to (T,G)-A--L in the splenic focus assay, (T,G)-A--L-primed xid mice could provide help as recipients for stimulation of wild-type primary and secondary B cells. It seems likely that the B2 subset contributes most of the splenic focus response to (T,G)-A--L. The fine specificities of antibodies produced by neonatal, xid, and adult (wild-type) B cell clones were analyzed using analogues of (T,G)-A--L. A specificity shift was observed between the adult primary and secondary antibody responses to (T,G)-A--L. Less than 10% of adult primary clones produced antibodies cross-reactive on (Phe,G)-A--L (recognizing A--L determinants or Phe,Glu determinants), whereas more than 70% of primary clones produced Tyr,Glu side-chain specific antibodies cross-reactive on GT. The percentage of clones producing GT-binding antibodies diminished in the secondary response, while the percentage of clones producing antibodies cross-reacting on (Phe,G)-A--L increased. Neonatal clones also produced mostly GT-binding antibodies but gave a higher percentage of (Phe,G)-A--L-cross-reacting antibodies than adult primary clones. The specificities of secondary antibodies produced by xid and wild-type B cell clones were dissimilar. First, xid secondary clones were "primary-like" in that no anti-A--L antibodies were detected. Second, clones whose antibodies bound side-chain determinants but not GT were produced in higher frequency by xid than by wild-type secondary B cells. The differential responsiveness of B cell subsets to antigen and regulatory signals may influence memory B cell generation and the specificity of antibodies produced in the primary vs secondary response.
采用脾集落试验从新生小鼠、成年小鼠和xid小鼠中克隆B细胞，以检测它们对（T,G）-A-L的初次和二次应答。成年小鼠对（T,G）-A-L的前体细胞频率在新生个体发育后期才达到。在脾集落试验中，xid小鼠的初级B细胞对DNP-HY有反应，但对（T,G）-A-L无反应。来自用（T,G）-A-L免疫的xid小鼠的次级B细胞频率小于或等于来自野生型（非xid或X/Xxid杂合子）小鼠的次级B细胞频率的10%。尽管在脾集落试验中xid B细胞对（T,G）-A-L反应较弱，但用（T,G）-A-L免疫的xid小鼠作为受体可以为野生型初级和次级B细胞的刺激提供辅助。似乎B2亚群对（T,G）-A-L的脾集落反应贡献最大。使用（T,G）-A-L的类似物分析了新生小鼠、xid小鼠和成年（野生型）B细胞克隆产生的抗体的精细特异性。在成年小鼠对（T,G）-A-L的初次和二次抗体应答之间观察到特异性转变。成年小鼠的初级克隆中不到10%产生的抗体与（Phe,G）-A-L交叉反应（识别A-L决定簇或Phe,Glu决定簇），而超过70%的初级克隆产生与GT交叉反应的Tyr,Glu侧链特异性抗体。在二次应答中，产生GT结合抗体的克隆百分比降低，而产生与（Phe,G）-A-L交叉反应抗体的克隆百分比增加。新生克隆也大多产生GT结合抗体，但与成年小鼠初级克隆相比，产生与（Phe,G）-A-L交叉反应抗体的克隆百分比更高。xid小鼠和野生型B细胞克隆产生的二次抗体的特异性不同。首先，xid小鼠的二次克隆“类似初级克隆”，因为未检测到抗A-L抗体。其次，xid小鼠产生的抗体结合侧链决定簇但不结合GT的克隆频率高于野生型次级B细胞。B细胞亚群对抗原和调节信号的不同反应性可能影响记忆B细胞的产生以及初次应答与二次应答中产生的抗体的特异性。
