Lambda chain

The presence of oligoclonal free kappa and lambda chains in CSF is a sensitive indication for recent antigenic immune response within the central nervous system, comparable with IgM. The detection of oligoclonal free kappa chains in CSF supports the diagnosis of multiple sclerosis. In addition, free light chains can also be found in the CSF of patients having inflammatory diseases of the central nervous system (LI). 

Genes Encoding Human and Mouse Lambda Chains... 

Appella, E. (1971). Amino acid sequences of two mouse immunoglobulin lambda chains. Proc. Natl. Acad. Sci. USA 68, 590-594. 

Appella, E. Perham, R.N. (1968). Amino-terminal sequences of two mouse lambda chains. J. Mol. Biol. 33,963-966. 

Antibodies Goat antibody to mouse lambda chain (Sera-Lab, Cnndey )own, UK) rabbit antigoat IgG conjugated to alkaline phosphatase (Sigma) see also Note 5). 

Fill (200 pL) wells with goat antimouse lambda chain diluted 1 1000 in PBST and incubate for 1 h at 37°C. Empty and wash three times with PBST. 

They then plotted variability in human and mouse k and X chains (as a group) as a function of position in the amino acid sequence. A similar plot based only on the nine human V i sequences (seven complete, two partial) in Fig. 4.2, is presented in Fig. 4.4. It is evident that the regions of major variability are near positions 30, 50, 95, and 106. A similar plot based on a sample which includes two additional k chains, but not Dav or Fin, was presented by Braun et al. (35). Figure 4.4 resembles quite closely the plot of Wu and Kabat, who included both kappa and lambda chains, and the mouse and human species, in their sample. 

Lambda chains are also distinguishable by deletions or insertions (as compared with k chains) occurring at characteristic positions in the amino acid sequence (Chapter 4). These represent a striking structural feature because many of the same deletions and insertions have been seen in all X chains studied, including those of the chicken as well as several mammalian species (118). Thus, deletions or insertions, once established, may be almost irreversible evolutionary events, probably because they cause important structural alterations. Their presence provides a strong basis for characterizing a polypeptide chain of a species under investigation as k or X. 

The fundamental unit of tertiary structure is the domain. A domain is defined as a polypeptide chain or a part of a polypeptide chain that can fold independently into a stable tertiary structure. Domains are also units of function. Often, the different domains of a protein are associated with different functions. For example, in the lambda repressor protein, discussed in Chapter 8, one domain at the N-terminus of the polypeptide chain binds DNA, while a second domain at the C-terminus contains a site necessary for the dimerization of two polypeptide chains to form the dimeric repressor molecule. 

Figure 8.3 The DNA-binding protein Cro from bacteriophage lambda contains 66 amino acid residues that fold into three a helices and three P strands, (a) A plot of the Ca positions of the first 62 residues of the polypeptide chain. The four C-terminal residues are not visible in the electron density map. (b) A schematic diagram of the subunit structure. a helices 2 and 3 that form the helix-turn-helix motif ate colored blue and red, respectively. The view is different from that in (a), [(a) Adapted from W.F. Anderson et al., Nature 290 754-758, 1981. (b) Adapted from D. Ohlendorf et al., /. Mol. Biol. 169 757-769, 1983.]...

Superficially, the lambda repressor protein is very different from lambda Cro. The polypeptide chain is much larger, 236 amino acids, and is composed of two domains that can be released as separate fragments by mild proteolysis. In repressor the domain responsible for dimerization is separate from the... 

All Light Chains Are Either Kappa or Lambda in Type... 

Immunohistochemical stains for kappa and lambda light chains were performed in the bone marrow specimens to determine the presence or absence of light chain preponderance or monoclonality. In all these cases, including those... 

Armed with this new tool, Schena et al. (1996) created a microarray of 1,046 human cDNAs of unknown sequence. They were derived from human peripheral blood lymphocyfes fransformed wifh Epsfein-Barr virus. Suitably sized inserts [>600 base pairs (bp)] were cloned into a lambda vector, subsequently infected into an Escherichia coli strain, and finally amplified by polymerase chain reaction (PCR) using 5 -amino-modified primers. The resulting 5 -amino-modified cDNA amplicons were then arrayed onto sily-lated microscope slides. Next, the expression levels in human Jurkat cells undergoing heat shock or phorbol ester induction were examined. 

The specific labeled separated protein fractions blotted on a nitrocellulose membrane or specific immunoflxation-separated protein fractions in polyacrylamide after isoelectric focusing make it possible to detect some additional bands in CSF, i.e., IgM, IgA, free kappa or lambda light chains of specific antibodies (i.e., antiherpes, anti-borrelia, or anti-HIV) (LI, M3). 

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