The main difference between kappa and lambda light chain is that the kappa light chain is encoded by chromosome 2 of the human genome, whereas the lambda light chain is encoded by chromosome 22 of the human genome.
The kappa and lambda light chains are the two types of light chains occurring in antibodies. The normal ratio between kappa and lambda light chains is 2:1 serum.
Key Areas Covered
1. What is Kappa Light Chain
– Definition, Structure, Function
2. What is Lambda Light Chain
– Definition, Structure, Function
3. Similarites Kappa and Lambda Light Chain
– Outline of Common Features
4. Difference Between Kappa and Lambda Light Chain
– Comparison of Key Differences
Key Terms
Kappa Light Chain, Lambda Light Chain
What is Kappa Light Chain
The Kappa light chain is one of the two types of polypeptide chains that occur in the antibodies in the form of light chains. This light chain is encoded by the p arm of chromosome 2. The exact region of the kappa light chain locus is 11.2 (2p11.2). Three genes of the region encode the kappa light chain. They are the V (variable), J (joining), and C (constant) genes. Apart from that, only one type of light chain occurs in an antibody. Therefore, the two light chains of the antibody are identical to each other.
Moreover, there are two regions in the light chain: the constant domain and the variable domain. The variable domain is important for the binding of antigens. Furthermore, the length of the light chain can be 211 to 217 amino acids. In addition, the constant region determines the type of light chain, whether it’s a kappa or lambda light chain.
Figure 1: Antibody
Furthermore, B lymphocytes either express the kappa light chain or lambda light chain. The type of light chain expression is fixed for the lifetime of the B lymphocyte. The other type of polypeptide chain is the lambda light chain. Moreover, the kappa light chain occurs in the serum in a 2:1 proportion in the serum. In addition, the increment of the levels of light chains indicates a disease condition such as kidney disease.
What is Lambda Light Chain
Lambda light chain is the second type of light chain that can occur in antibodies. The q arm region 11.22 on chromosome 22 is the location of the genes for the lambda light chain. Each antibody consists of two heavy chains and two light chains. The two types of light chains are the kappa and lambda light chains. Their locus consists of V (variable), J (joining), and C (constant) segments.
Figure 2: Antibody Structure: Heavy Chains (blue) and Light Chain (Green)
Moreover, during B cell development, the V segment binds to the J segment by recombination. Later, the C segment binds during the splicing of the RNA level. Recognition of antigens allows by the joining of different V segments with several J segments. Additional diversity can be obtained during B cell maturation by junctional diversity, random addition of nucleotides by terminal deoxynucleotidyltransferase, and by somatic hypermutation.
Similarities Between Kappa and Lambda Light Chain
- Kappa and lambda light chains are two types of light chains of antibodies.
- They occur in the 2:1 ratio in the serum.
- They increase proportionately, maintaining the normal ratio.
Difference Between Kappa and Lambda Light Chain
Definition
Kappa light chain refers to a polypeptide chain of one of the two types of light chains that are found in antibodies, while Lambda light chain refers to the other polypeptide chain occurring in the 2:1 ratio with the kappa light chain.
Encoded by
The kappa light chain is encoded by the p arm of chromosome 2, while the lambda light chain is encoded by the q arm of chromosome 22.
Proportion
Moreover, the kappa light chain occurs in two proportions in the serum, while the lambda chain occurs in a single proportion.
In Myeloma
The kappa chain is tested in kappa myeloma, while the lambda chain is tested in lambda myeloma.
Conclusion
In brief, kappa and lambda light chains are two types of light chains occurring in antibodies. The kappa light chain is encoded by the short (p) arm of chromosome 2. In terms of abundance, the kappa light chain is found in approximately twice the amount compared to the lambda light chain in the serum. On the other hand, the lambda light chain is encoded by the long (q) arm of chromosome 22. However, in contrast to the kappa light chain, it occurs in approximately equal proportion to the other type of light chain in the serum. Therefore, the main difference between the kappa and lambda light chains is their chromosomes and the proportion in the serum.
References:
Image Courtesy:
- “Antibody IgG2” By TimVickers at English Wikipedia – Own work (Public Domain) via Commons Wikimedia
- “AntibodyChains” By Yohan at fr.wikipedia – Own Work (CC-BY SA 3.0) via Commons Wikimedia
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