Genetic Association of the Porcine C9 Complement Component with Hemolytic Complement Activity

Area of Science:

• Immunology
• Genetics
• Animal Science

Background:

• The complement system is crucial for innate immunity, with the terminal pathway involving C9 in cell lysis.
• Understanding genetic variations in complement components can reveal insights into disease resistance.

Purpose of the Study:

• To investigate the association between porcine C9 gene single nucleotide polymorphisms (SNPs) and disease resistance traits.
• To analyze the impact of C9 SNPs on hemolytic complement activity in pigs.

Main Methods:

• Comparative sequencing of porcine C9 cDNA across multiple breeds.
• Genotyping of 417 F2 animals from a Duroc × Berlin miniature pig resource population.
• Association analysis of C9 SNPs with hemolytic complement activity before and after vaccination.

Main Results:

• Two SNPs were identified in the porcine C9 gene, one causing an amino acid substitution.
• European pig breeds showed higher allele frequencies for these SNPs compared to the Vietnamese breed.
• The substitution SNP was significantly associated with classical pathway hemolytic complement activity, influenced by genotype, vaccine type, and age.

Conclusions:

• Porcine C9 (pC9) is a potential candidate gene for enhancing general animal health and disease resistance.
• Genetic variations in pC9 influence complement system activity, offering targets for selective breeding.
• The study highlights the complex interplay between C9 genotype, vaccination, and complement pathway function in pigs.