Concentration of immnoglobulin G in plasma varies among 6C.7 recombinant congenic strains of chickens

Abstract

Chicken Lines 63 and 72 were inbred during selection for resistance or susceptibility to viral-induced tumors. A sandwich ELISA assay was adapted to define the milligrams per milliliter of Ig-gamma (IgG) in plasma from chickens of Lines 63 and 72, as well as 19 recombinant congenic strains (RCS). Each RCS resulted from a 7(2) x 6(3) F(1) and two backcross matings using 63 as the recurrent female line. The IgG levels in the RCS were evaluated after four to seven generations of sib-matings, when each RCS was becoming inbred and fixed for a different 12.5% of the 72 genome. In three generations approximately 24-wk-old chickens of Line 72 had higher levels of plasma IgG than chickens of Line 63 (P < 0.05). None of the RCS had repeatable IgG levels comparable to Line 7(2). However, in the last two generations, two of the 18 RCS had higher IgG levels than nine with low IgG levels (P < 0.05). There was no correlation between an IgG level of a RCS and resistance to Marek's disease. It was concluded that selected RCS may be useful for identifying genes that determine differences in IgG levels, as well as for understanding the relationship between genes, IgG levels, and other traits that differ between Lines 63 and 72.

Genomic Variation between Genetic Lines of White Leghorns Differed in Resistance to Marek’s Disease

“…Based on the above findings our long-term goal is to determine what are the genetic and epigenetic differences between the genetic lines of chickens that modulate the differential protective efficacy of MD vaccines against vv+ MDV challenge when the other factors listed above are similar or identical. Earlier studies showed the primary lymphoid organ size and IgG level differ between the lines 6 3 and 7 2 [34,35]. Data from our recent collaborative studies showed that profiles of global gene expression with or without MDV challenge differ between the highly inbred line 6 3 and 7 2 and one recombinant congenic strain [36].…”

Genetics and vaccine efficacy: Host genetic variation affecting Marek’s disease vaccine efficacy in White Leghorn chickens

“…Soon after initiating the development of the RCS, limited chickens from most of the RCS were infected with the mildly pathogenic JM/102W virus (a virulent strain of MDV) and more chickens from RCS M and W had MD than chickens in other RCS (P < 0.05; Bacon et al, 1996). Additional studies using relatively small numbers of chicks infected with the JM/102W virus indicated that RCS P and X were also relatively susceptible to MD (Yonash et al, 2002). Recently, passage 50 of the 648A strain has been evaluated for pathogenicity.…”

“…If these PI value differences are repeatable in additional experiments, this line of studies will have identified at least 2 RCS that can be useful for defining genes determining vaccine protection. The details of how one can make RCS F 2 or backcrosses to evaluate chickens for genes determining a trait have been discussed elsewhere (Yonash et al, 2002;Zhang et al, 2006).…”

Severe necrotic dermatitis in the combs of line 63chickens infected with Marek’s disease virus

“…Previous studies have shown that the resistant line 6 3 has a lower concentration of serum IgG, lower numbers of CD4 + T cells and B cells, a lower concentration of plasma dopamine, and a lower concentration of IFN in the supernatant of white blood cell (WBC) culture stimulated with phytohaemagglutinin (PHA), when compared with susceptible lines 7 2 or 15 I 5. In contrast, flow cytometric analysis has shown that the resistant line 6 3 has a higher percentage of CD8 + T cells than susceptible lines 7 2 and 15 I 5 (Bacon & Palmquistt, 2002;Dennis et al, 2006;Yonash et al, 2002).…”