从兔外周血直接克隆IgG重链可变区 

目的 从兔外周血总RNA中直接扩增出IgG重链可变区基因。方法 先从IMGT/GENE-DB数据库中获取编码大耳白兔免疫球蛋白（Ig）重链可变区（VH）的3个胚系基因片段VSUB>H/SUB>（IGHV）、D（IGHD）和JSUB>H/SUB>（IGHJ）,以及编码γ重链恒定区（CH）基因Cγ（IGHG）的cDNA序列,然后设计嵌套引物,以兔外周血总RNA为模板,进行RT-PCR和Nested-PCR扩增,产物经胶回收后克隆到T载体,随机挑选白色克隆测序,最后将序列用Bioedit软件的Local Blast功能比对出Cγ的基因型,同时提交到IMGT/V-QUEST分析出所属的VH、D和JH胚系基因。结果 获得25个克隆的插入子序列,每个克隆均为兔IgG重链可变区的编码基因,且包含了完整的VSUB>H/SUB>、D、JSUB>H/SUB>胚系基因片段,以及Cγ基因     

HLA—A2单抗轻链可变区基因的克隆及其序列分析

以ＨＬＡ－２单抗ｍＲＮＡ为模板，设计了３对特异性引物，采用ＰＣＲ技术，扩增和克隆出单以链可变区基因并应用双脱氧链式终止法及计算机基因文库测定和分析了其氨基酸和核苷酸序列。结果证明，本组单抗轻链由不同的基因家族编码。     

抗人ClqMcAb轻链可变区基因结构特点

运用计算机进行基因序列分析在分子生物学研究中起重要作用，已被越来赵多地用于研究大量累积的序列数据，获得许多重要发现。对抗人Ｃｌｑ轻链可变基因的分析结果表明：ＣｌｑＶＬ属鼠ＩｇＶＫ基因家族，但与其它种属的Ｉｇ基因也显示较高同源性。     

抗人C1q轻链可变区基因在E.coli中的表达

应用基因工程技术，将抗人Ｃ１ｑ轻链可变区基因的重组质粒ｐＧＥＭ－Ｃ１ｑＶＬ中分离，克隆进表达载体ｐＪＬＡ５０２。该表达截体含ＣＩＴｓ８５７抑制子基因，通过开温诱导法，重组表达子在宿主菌ＨＢ１０１中表达，获得抗人Ｃ１ｑ轻链可变区片段，ＳＤＳ－ＰＡＧＥ表明其分子量范围为１２－１３ＫＤ。这为进一步抗人Ｃ１ｑ小抗体的表达积累了经验，有利于用于抗原－抗体结构功能的研究。     

抗人ClqMcAb轻、重链可变区基因的克隆、序列分析及轻链可变区基因的表达（摘要）

抗人ＣｌｑＭｃＡｂ轻、重链可变区基因的克隆、序列分析及轻链可变区基因的表达（摘要）陈克敏，朱锡华应用ＰＣＲ技术，从一株抗人ＣｌｑＭｃＡｂ杂交瘤细胞基因组ＤＮＡ及反转录合成ｃＤＮＡ中，扩增、克隆分别获得抗人Ｃｌｑ轻、重链可变区基因，序列分析表明：抗人Ｃ...     

抗人C1q轻链可变区的序列结构分析

将抗人Ｃ１ｑ轻链可变区（ｐＣ１ｑＶＬ）氨基酸序列与Ｓｗｉｓｓ蛋白质库的序列进行同源性检索及与已知的ＩｇＶ功能区相关分子进行对准比较，检索了同源性积分子的统计学意义，结果表明ｐＣ１ｑＶＬ归属鼠ＩｇＶＫ，符合Ｉｇｋ轻链可变区的基本特征。同时进行了亲水性、可及性分析及二级结构预测，这为利用构象分析方法研究ｐＣ１ｑＶＬ构象特点打下了基础。     

从人外周血淋巴细胞扩增抗体可变区基因的3种方法

介绍了从人外周血淋巴细胞（ＰＢＬ）以传统方法提取总ＲＮＡ再行反转录ＰＣＲ（ＲＴ－ＰＣＲ）、以Ｔｒｉｚｏｌ Ｒｅａｇｅｎｔ提取ＲＮＡ再行ＲＴ－ＰＣＲ以及细胞内直接ＲＴ－ＰＣＲ等３种方法扩增人抗体可变区（Ｖ区）基因的方法并作了比较。３种方法均扩增出了人抗体ＶＨ、Ｖκ、Ｖλ基因，从方法的简便及结果的可靠等方面综合考虑，作者推荐以Ｔｒｉｚｏｌ Ｒｅａｇｅｎｔ提取ＲＮＡ再行ＲＴ－ＰＣＲ扩增的方法。     

抗人C1q McAb轻链可变区基因结构特点

运用计算机进行基因序列分析在分子生物学研究中起重要作用，已被越来越多地用于研究大量累积的序列数据，获得许多重要发现。对抗人Ｃ１ｑ轻链可变基因（Ｃ１ｑＶ_Ｌ）的分析结果表明：Ｃ１ｑＶＬ属鼠ＩｇＶＫ基因家族，但与其它种属的Ｉｇ基因也显示较高同源性。它的另─个显著特点是与自身抗体编码基因高度同源。研究结果对我们进─步认识抗－Ｃ１ｑ抗体生理、病理作用具有─定价值。     

抗人Clq轻链可变区基因在E．coli中的表达

应用基因工程技术，将抗人Ｃｌｑ轻链可变区基因（ＣｌｑＶ＿Ｌ）由重组质粒ｐＧＥＭ－ＣｌｑＶ＿Ｌ中分离，克隆进表达载体ｐＪＬＡ５０２。该表达载体含ＣＩＴｓ８５７抑制子基因，通过开温诱导法，重组表达子在宿主菌ＨＢ１０１中表达，获得抗人Ｃｌｑ轻链可变区片段，ＳＤＳ－ＰＡＧＥ表明其分子量范围为１２～１３ＫＤ。这为进一步抗人Ｃｌｑ小抗体的表达积累了经验，有利于用于抗原－抗体结构功能的研究。     

抗HBV中和抗体MA18/7轻链可变区VL与GFP融合蛋白的表达及生物活性测定

目的 :在大肠杆菌中表达抗HBV中和抗体MA18/7轻链可变区基因 (VL)与增强型绿色荧光蛋白 (EGFP)的融合蛋白 ,并测定其生物学活性。方法 :应用基因工程技术 ,将EGFP基因克隆到载体pTO T7中构建原核表达载体。然后将MA18/7的VL基因按照读码框插入到无终止密码子TAA的EGFP基因的 5′末端 ,构建融合蛋白表达载体。通过ELISA和相对荧光强度测定在大肠杆菌中表达的融合蛋白的活性。结果 :构建了EGFP MA18/7 VL 表达载体。SDS PAGE表明 ,融合蛋白主要以包涵体的形式存在。荧光测定显示 ,融合蛋白保持了GFP的荧光性质。ELISA的结果表明 ,融合蛋白与重链可变区 (VH)片段结合成的Fv ,能特异性地识别HBVpre S1抗原。结论 :成功地获得具有良好生物学活性的融合蛋白 ,可用于进一步的研究。     

Immunohistochemical study of immunoglobulin light chain amyloidosis with antibodies to the immunoglobulin light chain variable region

To detect immunoglobulin (Ig) light chain amyloidosis (AL amyloidosis) in formalin-fixed, paraffin-embedded tissue sections by immunohistochemistry, polyclonal antibodies were generated against synthetic peptides corresponding to amino acids 1-19 of the Ig lambda light chain V lambda VI subgroup (anti-V lambda VI (1-19)) and the Ig kappa light chain Vkappa I subgroup (anti-Vkappa I (1-19)). Anti-V lambda VI (1-19) antibody reacted with amyloid deposits in 21 of 22 Alambda amyloidosis cases, and anti-Vkappa I (1-19) antibody reacted with amyloid deposits in 10 of 11 Akappa amyloidosis cases. Immunoreactivity varied in intensity by case and within specimens. Surprisingly, amyloid deposits were positive for anti-V kappa I (1-19) staining in one case of Alambda amyloidosis. Analysis of anti-V lambda VI (1-19) and anti-Vkappa I (1-19) antibody reactivity by ELISA showed some cross-reactivity with peptides other than antigen peptides. The antibodies were not reactive in all cases of AL amyloidosis examined but may be useful, together with anti-Ig constant region antibodies, for immunohistochemical diagnosis of AL amyloidosis.     

Diversity of expressed V and J regions of immunoglobulin light chains in Xenopus laevis

In Xenopus laevis, two immunoglobulin light chain isotypes, designated L1 or ? and L2 or σ, have been identified. The genomic organization of the L1 locus has been described previously: a constant (C) gene segment is preceded by a joining (J) gene segment; in addition, there are many cross-hybridizing variable (V) gene segments. To evaluate the extent of sequence diversity of L1 V regions, we screened three cDNA libraries, constructed from mitogen-stimulated Xenopus splenocytes, with probes for the C or the J gene segment. Eighteen cDNA clones that contain complete or truncated V regions were chosen for sequence analysis. The C regions of all clones are identical or nearly identical to the genomic C gene segment; the V regions are greater than 80 % identical in nucleotide sequence and are presumably derived from a single family of V gene segments. Although framework regions are nearly identical, complementarity-determining regions are quite diverse. The expressed J segments fall into distinct groups, suggesting the presence of more than one germ-line J segment. Therefore, a genomic library was screened with a J region probe. A clone overlapping with the previously identified J- C clone, and containing four additional J gene segments, was isolated. All five J gene segments are very similar and three are identical in nucleotide sequence. Each of the three distinct germ-line J sequences is represented in the set of cDNA clones, suggesting that combinatorial diversification occurs; imprecision of V-J joining also appears to contribute to variability. Overall, these results suggest that the immunoglobulin repertoire in this species is not significantly restricted by a limitation in the diversity of light chain V regions.     

Modulation of in vitro immunoglobulin synthesis of human peripheral blood mononuclear cells by nicotine and cotinine

The influence of nicotine and its main metabolite cotinine on the spontaneous and cytokine-induced immunoglobulin synthesis was studied. The immunoglobulin (G,A) synthesis of peripheral blood mononuclear cells was altered by nicotine donor dependently in the concentration range from 10–6 to 10^–8 M. Cotinine also modulates immunoglobulin (G, A) synthesis. The effective concentration range is about 100 fold higher. Only marginal effects on IgM synthesis were observed. Neither nicotine nor cotinine showed any effect on IgE production or on the IgE class switch. Moreover, both agents induced the production of the cytokines interleukin-1, –2, –3, –4, and –6. Therefore it is suggested that the strongly donor-dependent heterogeneity in the response to nicotine or cotinine is the result of the fine balance of theinduced cytokines.Abbreviations IFN interferon - IL interleukin - PBMC peripheral blood mononuclear cells - TNF tumor necrosis factor Correspondence to: A. Fischer     

cDNA sequence and organization of the immunoglobulin light chain gene of the duck, Anas platyrhynchos

A cDNA was cloned which encoded an immunoglobulin (Ig) light (L) chain of the White Pekin duck. The organization of the variable (V) and constant (C) domains was analyzed by genomic Southern blotting. The duck L chain gene has a similar chromosomal organization to that of the chicken, with a single λ-like C region and multiple V_L hybridizing elements. The amino acid sequence of the V_L region of the White Pekin duck L chain showed 88% identity with the Muscovy duck and 87% identity with the chicken, the J_L region showed 92% identity with these species, and the C_L region showed 88% identity with Muscovy duck and 66% with chicken. The constraints imposed by the gene-conversion mechanism of generating antibody diversity might account for the similarities of the avian V region sequences.     

Variability of the immunoglobulin light chain in the Siberian sturgeon, Acipenser baeri

All sturgeon VL segments isolated in this study belong to a single family, VLI, which can be divided into two subfamilies. Of the 79 cDNA clones isolated, 76 belong to the larger subfamily, VLIa, and only 3 clones constitute the smaller subfamily, VLIb. To evaluate variability, the Shannon entropy was estimated for each individual amino acid position, and to facilitate comparisons of variability between species the mean entropy of the CDR regions was calculated. In such a comparison, the sturgeon was found to have CDR1 and CDR3 variability approaching those found in mouse and clawed frog, but showed very low variability for CDR2. Amino acid position 50 does however display variability in the range of mouse and clawed frog. It is further confirmed that the sturgeon has numerous J segments, but that the junctional diversity does not contribute greatly to the diversity of the light chain. Comparisons of cDNA clones and a genomic VL segment indicate that the VL undergoes changes, particularly in the CDR regions, in a manner that can be explained by somatic hypermutation and/or gene conversion.     

5'-RACE法扩增抗人乳头瘤病毒16型L1蛋白单克隆抗体轻链可变区基因及序列分析

目的 获得抗人乳头瘤病毒16型(HPV16)L1蛋白单克隆抗体的轻链可变区(VL)基因并分析序列.方法 从分泌抗HPV16L1蛋白单克隆抗体的杂交瘤细胞中提取总RNA,逆转录形成cDNA,用5'-RACE策略扩增抗体轻链可变区基因,经琼脂糖凝胶电泳鉴定,并测序及进行序列分析.结果 VL基因全长336bp,编码112个氨基酸,基因测序结果符合小鼠抗体轻链可变区特征.结论 5'-RACE法成功获得了抗HPV16L1蛋白的单克隆抗体轻链可变区基因的真实序列,为基因工程抗体研究奠定了良好基础.     

Four primordial immunoglobulin light chain isotypes, including lambda and kappa, identified in the most primitive living jawed vertebrates

The discovery of a fourth immunoglobulin (Ig) light (L) chain isotype in sharks has revealed the origins and natural history of all vertebrate L chains. Phylogenetic comparisons have established orthology between this new shark L chain and the unique Xenopus L chain isotype sigma. More importantly, inclusion of this new L chain family in phylogenetic analyses showed that all vertebrate L chains can be categorized into four ancestral clans originating prior to the emergence of cartilaginous fish: one restricted to elasmobranchs (sigma-cart/type I), one found in all cold-blooded vertebrates (sigma/teleost type 2/elasmobranch type IV), one in all groups except bony fish (lambda/elasmobranch type II), and one in all groups except birds (kappa/elasmobranch type III/teleost type 1 and 3). All four of these primordial L chain isotypes (sigma, sigma-cart, lambda and kappa) have maintained separate V region identities since their emergence at least 450 million years ago, suggestive of an ancient physiological distinction of the L chains. We suggest that, based upon unique, discrete sizes of complementarity determining regions 1 and 2 and other features of the V region sequences, the different L chain isotypes arose to provide different functional conformations in the Ig binding site when they pair with heavy chains.     

Mapping of the duplicated rabbit immunoglobulin kappa light chain locus.

The rabbit has two isotypic forms of the immunoglobulin kappa light chain, K1 and K2, which probably arose by duplication. In the normal rabbit, only traces of K2 light chains are produced. However, K2 levels are elevated in allotype-suppressed rabbits and in the Basilea strain which does not produce K1 because of a K1 mRNA splice site mutation. Previous cloning and sequencing showed that each isotype has its own set of J kappa genes but it was not known whether the two isotypes utilize shared or separate sets of V kappa genes. In addition, although genetic linkage of allotypes associated with the K1 and K2 genes has been demonstrated, physical linkage had not been previously demonstrated by overlapping cosmid or phage clones. We used pulsed field and transverse alternating field electrophoresis to obtain megabase maps and to estimate the size of the duplication of the rabbit kappa light chain locus. We found that the two C kappa genes are about 1 megabase apart. One explanation for the poor expression of K2, could be great physical distance from V kappa genes. However, we found that there are V kappa, J kappa and C kappa 2 genes within a approximately 105-kb fragment. Thus, physical distance of V kappa from C kappa 2 may not be the basis for poor K2 expression.