RT Journal Article SR Electronic(1) A1 Baigent, Susan J. A1 Ross, L. J. N. A1 Davison, T. F.YR 1998 T1 Differential susceptibility to Marek's disease is associated with differences in number, but not phenotype or location, of pp38+ lymphocytes JF Journal of General Virology, VO 79 IS 11 SP 2795 OP 2802 DO https://doi.org/10.1099/0022-1317-79-11-2795 PB Microbiology Society, SN 1465-2099, AB Flow cytometric and immunocytochemical techniques were used to quantify, identify and locate Marek’s disease herpesvirus (MDV)-infected lymphocytes in lymphoid organs of infected chickens, by expression of the virus antigen pp38. Two closely related lines of chicken, one susceptible to Marek’s disease (line 72) and another resistant (line 61), were infected at 2 weeks of age and compared at 10 sampling times between 0 and 50 days post-infection. In both lines 61 and 72, pp38 lymphocytes were detected at 4–6 days in the spleen, thymus and bursa. pp38 cells could not be detected from day 8 onwards. In both lines, pp38 lymphocytes were located in the peri-ellipsoidal area of the spleen, the medulla of the thymic lobes and the medulla of the bursal follicles. In both lines, pp38 cells were predominantly B lymphocytes, but CD4 and CD8 TCRαβ T lymphocytes were also detected in the thymus and spleen. For each organ, the mean number of pp38 lymphocytes was greater in line 72 than in line 61. pp38 lymphocytes were not detected in the peripheral blood at anytime. The data show that the differential susceptibility of lines 61 and 72 to the development of Marek’s disease lymphoma is not attributable to differences in phenotype or location of pp38 lymphocytes, or the time of expression of pp38. However, susceptibility is associated with greater numbers of pp38 lymphocytes., UL https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-79-11-2795