Isolation and sequence of sheep immunoglobulin E heavy-chain complementary DNA

Area of Science:

• Immunology
• Molecular Biology
• Genetics

Background:

• Immunoglobulin E (IgE) plays a crucial role in allergic responses and defense against parasites.
• Understanding the molecular structure of IgE is essential for developing targeted therapies and diagnostics.

Purpose of the Study:

• To isolate and sequence the complementary DNA (cDNA) encoding the sheep immunoglobulin E heavy (IgE H) chain.
• To characterize the variable (V) and constant (C) regions of the sheep IgE H-chain.
• To compare the derived amino acid sequence with epsilon-chains from other species.

Main Methods:

• Polymerase chain reaction (PCR) was used to synthesize a fragment of the sheep IgE constant H (epsilon)-chain.
• A cDNA library was prepared from parasite-stimulated sheep lymph node mRNA.
• The synthesized fragment was used as a probe to screen the cDNA library, leading to the isolation of a recombinant clone.
• The isolated cDNA encoding the sheep IgE H-chain was sequenced.

Main Results:

• A complete sheep IgE H-chain cDNA of 1802 base pairs was isolated and sequenced.
• The nucleotide sequence codes for a complete IgE H-chain, including both variable (V) and constant (C) regions.
• Amino acid sequence comparison revealed conserved cysteine and tryptophan residues and variable glycosylation sites, highlighting homologies and differences with other species' epsilon-chains.

Conclusions:

• The study successfully characterized the sheep IgE H-chain at the molecular level.
• The findings provide valuable insights into the structural conservation and variation of IgE across species.
• This information can contribute to a better understanding of immune responses in sheep and comparative immunology.