Tritiated Thymidine Labeling of Normal and NDV-Infected Chick Nasal Epithelial Cells

Summary The tritiated thymidine labeling index in nasal turbinate epithelia was determined in chicks which had been infected 24 hr with Newcastle disease virus and in control chicks. Control indices were calculated at periods from 1 hr to 18 days, indices in infected epithelia at two hr intervals 1-57 hr after thymidine injection. Mean control values were consistently higher in outer-surface epithelia than in the shallower inner-surface system (3.0:1.1); peak labeling was at 12 hr. The proliferative compartment in the ciliated cell system was between basal stem cells and superficial end cells; 7% of labeled cells were in the end cell position at 48 hr; about 40% were in this position at all periods between 7 and 18 days. Indices were sharply reduced in infected turbinates in all compartments in all mucociliated epithelia at all times between 25 and 81 hr postinoculum. Lymphocyte control indices peaked at 12 hr, fell somewhat below control values for 35 hr postinfection. Indices in turbinate cartilage cells were 0.6% in controls, 0.1% in infected chicks.