Complementary DNA for a human subgroup IV immunoglobulin lambda-chain

Area of Science:

• Immunogenetics
• Molecular Biology

Background:

• Human monoclonal antibodies are vital tools in diagnostics and therapeutics.
• Understanding the genetic basis of antibody production, particularly immunoglobulin lambda-chains, is essential.

Purpose of the Study:

• To clone and characterize the cDNA encoding a human immunoglobulin lambda-chain (V lambda 3C4) from a hybridoma producing an antibody against a human sperm surface antigen.
• To investigate the genetic organization and variability of the V lambda IV subgroup genes in the human genome.

Main Methods:

• cDNA cloning of the immunoglobulin lambda-chain.
• Nucleotide sequencing and amino acid sequence deduction.
• Southern blot analysis of human genomic DNA.
• Restriction enzyme fragment length polymorphism (RFLP) analysis.

Main Results:

• Successfully cloned the p3C4 lambda 5 cDNA encoding the V lambda 3C4 lambda-chain.
• The deduced amino acid sequence of V lambda 3C4 showed high relatedness to SHV lambda protein (subgroup IV).
• Southern blot analysis identified at least 8 cross-hybridizing genes belonging to the V lambda IV subgroup.
• RFLP analysis indicated the presence of genetic polymorphism in the V lambda 3C4 gene among normal individuals.

Conclusions:

• The cloned V lambda 3C4 gene is a member of the human immunoglobulin lambda-chain subgroup IV.
• The V lambda IV subgroup is represented by multiple genes in the human genome.
• Genetic variations within the V lambda 3C4 gene locus exist in the human population, potentially influencing antibody diversity.