GENES OF CHICKEN MHC REGULATE THE ADHERENCE ACTIVITY OF BLOOD MONOCYTES IN ROUS SARCOMAS PROGRESSING AND REGRESSING LINES

The influence of the chicken major histocompatibility (B) complex (MHC ) on the adherence potential of monocyte-derived macrophages was exami ned using the congenic chicken lines CB and CC. These Lines represent well-defined genetic models for the study of resistance (CB) or suscep tibility (CC) to the progressive growth of Rous sarcomas. Using a mono clonal antibody specific for chicken monocytes/macrophages, CB and CC chickens were shown by flow cytometry analyses to have similar proport ions of peripheral blood monocytes. However, when the glass-adherence potential of these cells was compared during incubation in tissue cult ure medium over 24, 48 and 72 h at 40 degrees C, significant differenc es were seen between cells from these two inbred Lines. After 24 and 4 8 h, glass-adherence by CB cells was 2-3 fold higher than that of CC c ells. After 72 h this difference decreased to 1.5 fold. At 24 and 48 h , the adherent CB macrophages also appeared about 1.5 times larger tha n those of CC chickens. Genetic analysis using FI hybrids (CBxCC) show ed that this trait is regulated by a dominant gene that segregates wit h the B12 haplotype in the backcross generation F(1)xCC. From the resu lts obtained with the recombinant congenic lines CB.R1 and CC.R1, we c onclude that the gene regulating adherence potential is localized with in the B-F/L region of the chicken MHC. About 50% of adherent cells we re able to phagocytose opsonised FITC-labelled Zymosan particles. The level of nitric oxide production in vitro by CB and CC macrophages was equal. The importance of cells of the mononuclear phagocyte system fo r the response to Rous sarcoma virus (RSV) infection was studied in CB chickens using the anti-macrophage agents silica, carrageenan, and Cl 2MDP, encapsulated in liposomes. In those chickens treated with silica and carrageenan, we observed progressive growth of RSV-induced tumors . The graft-versus-host reactivity of peripheral blood lymphocytes (PB L) of treated chickens was comparable to controls. In vitro nitric oxi de production by macrophages from silica-treated chickens was higher t han by macrophages from untreated controls. (C) 1998 Elsevier Science B.V. All rights reserved.