Molecular characterization of VDJ transcripts from a newborn piglet

Area of Science:

• Immunology
• Genetics
• Molecular Biology

Background:

• The development of the immunoglobulin heavy chain (VH) repertoire is crucial for adaptive immunity.
• Understanding the swine VH repertoire provides insights into immune system evolution and function.

Purpose of the Study:

• To characterize the expressed VH repertoire in newborn piglets.
• To investigate the mechanisms of VH gene usage and diversity in swine.

Main Methods:

• Cloning and sequencing of 42 VH transcripts from mesenteric lymph nodes.
• Analysis of gene usage, somatic mutation, and junctional diversity.
• Comparison with germline sequences and other species.

Main Results:

• The expressed VH repertoire in newborn piglets is restricted and largely germline.
• Extensive and asymmetrical junctional diversity was observed in CDR3.
• Hybrid clones suggest somatic gene conversion compensates for a limited number of VH genes.

Conclusions:

• Swine newborns possess a mature but restricted VH repertoire with extensive junctional diversity.
• Somatic gene conversion may compensate for a limited germline VH gene pool.
• Preferential expression of VHA is likely a selection phenomenon.