Inflammatory function of macrophages from chickens with B‐recombinant haplotypes

Abstract
Both in vivo macrophage activation and in vitro monocyte activation were compared using chickens homozygous for each of two biochemically and serologically similar B-complex recombinant (B(F2-G23)) haplotypes. Chickens carrying the parental (non-recombinant) B haplotypes (B2 and B23) were included for relative comparison, although the genetic backgrounds for these strains were different from the background of the recombinants. Elicited peritoneal macrophages from R4/R4 (international designation B(2r3)) chickens expressed levels of sheep erythrocyte phagocytosis which were significantly higher (P< 0.05) than those from R2/R2 (B(2rl)) chickens. Differences between chickens with B genotypes were analogous to the differences demonstrated previously between B2/B2 and B23/B23 chickens. Similarly, lipopolysaccharide (LPS)-activated monocytes from R4/R4 chickens also expressed significantly higher (P< 0.05) levels of phagocytosis when compared with R2/R2 and B23/B23. In both cases, the functional level of macrophages from R2/R2 chickens was similar to that of B23/B23 cells, whereas macrophages from R4/R4 chickens were similar in functional capacity to those from B2/B2 chickens. These results suggest that R2 and R4 recombinants, despite their demonstrated similarities, may differ in DNA regions which include genetic factors controlling macrophage responsiveness.