Molecular cloning, expression pattern and chromosomal mapping of pig CD69

Area of Science:

• Immunology
• Molecular Biology
• Genetics

Background:

• CD69 is a type II transmembrane receptor of the C-type lectin family, typically found on activated leukocytes.
• Understanding CD69 expression in pigs is crucial for immune system research.

Purpose of the Study:

• To clone and characterize the pig CD69 gene and its expression.
• To investigate the potential of pig CD69 as an immune cell activation marker.

Main Methods:

• Reverse transcription polymerase chain reaction (RT-PCR) was used to clone pig CD69 cDNA.
• Sequence identity analysis was performed comparing pig CD69 to homologous proteins in other species.
• RT-PCR was employed to detect CD69 mRNA expression in various pig cell types and tissues under different conditions.

Main Results:

• Pig CD69 cDNA has an open reading frame encoding 200 amino acids, showing significant sequence identity with cow, human, and mouse CD69.
• A splicing isoform lacking the transmembrane domain was identified.
• Pig CD69 mRNA was detected in activated peripheral blood leukocytes (PBL), NK cells, macrophages, monocytes, and granulocytes, but not in resting cells.
• Expression was induced by various stimuli including PMA, PHA, LPS, and specific monoclonal antibodies (mAbs).
• CD69 mRNA was found in immune organs like bone marrow, spleen, thymus, and lymph nodes, but not in muscle, mammary gland, or pig kidney cells (LLC-PK(1)).

Conclusions:

• The pig CD69 gene is located on Chromosome 5q25, in proximity to the NKG2D gene, suggesting the presence of the NK gene complex.
• Pig CD69 serves as a reliable activation marker for both innate and adaptive immune cells in pigs.