The Diverse Major Histocompatibility Complex Haplotypes of a Common Commercial Chicken Line and Their Effect on Marek’s Disease Virus Pathogenesis and Tumorigenesis

Figure 1. (A) Alleles of BLB1, BLB2, BF1 and BF2 genes found as haplotypes in VALO SPF chickens, correlated with standard names of MHC haplotypes, except for B9:02 named after the BF2 allele, which is a variant of the BF2 allele in the standard B9 haplotype. (B) Frequency distribution of MHC haplotypes in these batches of VALO SPF chickens (n = 330).

Figure 2. (A) Kaplan-Meier analysis of Marek’s disease incidence (scored as clinical signs of the disease) in wild type virus infected chickens with different MHC haplotypes (n.s., Mantel–Cox test; n = 88). (B) Tumor incidences in infected chickens with different MHC haplotypes as percentage of chickens with macroscopic tumors from all chickens that were experimentally infected (*p ≤ 0.5 indicates significant difference of B15/15 to all other haplotypes, Chi-square test; n = 88). (C) Mean number of affected organs harboring gross tumors per infected chicken (*p ≤ 0.5, Kruskal-Wallis test with a Dunn’s multiple comparison post-hoc test; n = 51).

Figure 3. (A) Kaplan-Meier analysis of Marek’s disease incidence in contact chickens with different MHC haplotypes (*p ≤ 0.5, Mantel–Cox test; n=55). (B) Tumor incidences in contact chickens with different MHC haplotypes as percentage of chickens with macroscopic tumors (n.s., Chi-square test; n=55). (C) Mean number of affected organs harboring gross tumors per contact chicken (n.s., Kruskal-Wallis test with a Dunn’s multiple comparison post-hoc test; n=21).