Research Note: MHCY haplotype impacts Campylobacter jejuni colonization in a backcross [(Line 6₁ x Line N) x Line N]...

Area of Science:

• Immunogenetics
• Poultry Science
• Microbial Pathogenesis

Background:

• The Major Histocompatibility Complex (MHC) region in chickens, particularly MHCY, is implicated in immune response regulation.
• MHCY harbors polymorphic MHC class I loci and genes from four additional families, suggesting a complex role in host defense.
• Previous studies identified heritable differences in Campylobacter jejuni colonization between White Leghorn research lines.

Purpose of the Study:

• To investigate the association between specific MHCY haplotypes and susceptibility to cecal colonization by Campylobacter jejuni in chickens.
• To identify genetic markers within the MHCY region that confer resistance or susceptibility to Campylobacter infection.

Main Methods:

• A backcross population of chickens [(Line 61 × Line N) × Line N] was challenged with Campylobacter jejuni.
• Cecal colonization levels were quantified 5 days post-infection and categorized into low or high colonization groups.
• Statistical analysis was performed to test for associations between MHCY haplotypes and bacterial counts.

Main Results:

• Seven MHCY haplotypes were segregating in the studied population.
• MHCY haplotype Y18 showed a significant association with low C. jejuni colonization (P = 3.00 × 10⁻⁵).
• MHCY haplotype Y11a was significantly associated with high C. jejuni colonization (P = 0.008).

Conclusions:

• Specific MHCY haplotypes play a significant role in modulating Campylobacter jejuni colonization in chickens.
• MHCY haplotype Y18 may confer resistance to C. jejuni colonization, whereas Y11a may increase susceptibility.
• These findings highlight the potential of targeting MHCY for improving poultry resistance to Campylobacter infections.