Immunodepressive effects of the recombinant 38 kd phosphorylated protein of Marek's disease virus

In this study immunodepressive effects of the 38 lid phosphorylated protein(pp38) of Marek's disease virus (MDV) were tested in chicks of SPF-origin. Birds were muscularly injected with purified pp38 or pq38(+) recombinant baculovirus-Sf9 cell lysates at 1 day of age and Immunized with mouse red blood cells (MRBC) at day 6 of age, sera were colleted 6-7 days after immunization and tested for hemagglutination (HA) titers. In 2 separated tests, HA titers to MRBC in purified pp38-treated chicks were significantly lower than that in controls, titers(log,) were 4.2+/-2.1(mean+/-sd,n=5) vs 6.8+/-1.2(n=5), 4.1+/-2.5(n=9) vs 7.1+/-1.2(n=7),p<0.005. In another 3 tests, chicks treated with pp38(+) Sf9 lysates of 10(6) cells also showed much lower HA titers than in control chicks treated with wild type baculovirus-Sf9 cell lysates, titers(log,) of each pairs were 3.56+/-1.9(n=9) vs 5.22+/-1.9(n=9), 3.94+/-2.2 (n=16) vs 5.5+/-2.0(n=16) and 5.12+/-2.0(n=17) vs 6.5+/-1.6 (n=16), p<0.005-0.025. However,pp38 did not influence immunoreaction to E. coli. The results indicated that MDV pp38 could depress antibody reactions in chicks to some antigens.