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The environmental contaminant 2,3,7,8-tetrachlorodibenzo-para-dioxin (TCDD) is a ligand for the aryl hydrocarbon receptor (AhR). TCDD is well-characterized to produce immunotoxicity, including suppression of antibody production. Previously we showed that TCDD inhibited myelin oligodendrocyte glycoprotein (MOG) peptide-specific IgG and attenuated disease in experimental autoimmune encephalomyelitis (EAE) model in mice. Thus, the purpose of this study was to characterize the effects of TCDD on IgG subclasses in EAE and in vitro and assess effects in B cells derived from various tissues. TCDD modestly suppressed intracellular IgG expression in splenocytes (SPLC), but not bone marrow (BM) or lymph node (LN) cells. To further understand TCDD’s effects on IgG, we utilized LPS and LPS + IL-4 in vitro to stimulate IgG3 and IgG1 production, respectively. TCDD preferentially suppressed IgG1+ cell surface expression, especially in SPLC. However, TCDD was able to suppress IgG1 and IgG3 secretion from SPLC and B cells, but not BM cells. Lastly, we revisited the EAE model and determined that TCDD suppressed MOG-specific IgG1 production. Together these data show that the IgG1 subclass of IgG is a sensitive target of suppression by TCDD. Part of the pathophysiology of EAE involves production of pathogenic antibodies that can recruit cytolytic cells to destroy MOG-expressing cells that comprise myelin, so inhibition of IgG1 likely contributes to TCDD’s EAE disease attenuation.

McDonald, A.L., Chen, T.C., Lott, B.D. and May, J.D. 2001. Component yields and tibia characteristics of broilders as affected by feed and light restriction. J. Appl. Anim. Res., 20: 1-14.Studies were conducted to deteriniiie the effects of restricted light aiid feed on coinpeiisctory gain in broilers, processing yields, coinpoiieitt distribution and tibia characteristics of broilers. Broiler chicks were p h c e d in 24 pens (60 birds/peii) with sexes separated. Three treatineiits were utilized: 1) ad libitum feed aiid 24 h light (L)(coiitrol); 2) restricted feed ( 9 h / d ) mid 24 h L (RF); and 3) restricted feed (9h/d) and 9L:15D (RLF). After 14 d , all broilers were chaiiged to 24 h L and ad libitum feed. At Weell G, eleven birds of siinilar weight per pen were processed ivith results iiidicatiiig tha.t inale control birds were heaviest. The ready-to-cook (RTC) carcass weights for the coiitrol birds were a.lso higher (PX05). The perceiit head a.iid iieck weights for the R F aiid RLF birds were higher. Females exhibited a, higher percei:t weight for intestine, abdorniiial fat pa.d, liver a i d lower percent 'For corrcspontlencc : Tcl:6(i2-325-3382; Fax: 662-325-8292; c-inail: tcchen~~poultry.insstate.cdu 1 .J. Appl. h i m . Res. New York dressed weight with ]LO treatiiieitt differences. Coiitrol inales exhibited the highest RTC as percent of live weights. The control aird RF females showed the highest total breast weight as percent of RTC, with the control inales exhibiting the highest perceirtage of breast and thigh meat. No differences were observed ainoiig treatineiits Kith regard to percentage solid content or breaking strength of the tibiae. Male tibiae exhibited higher breaking streiigth thait females, but were less dense. This study revealed iio advairtage to the poultry iiidustry or grower i n usirig restricted feediitg or a coinbiiiatioii of restricted feed aiid light.

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