MATERIALS AND METHODS

Virus. Reovirus type 1 (Lang strain) and type 3 (Dearing strain) have been described (8). Previously described recombinant clones (54, 63, 94, 103, 204, 802) had been isolated after mixed infection of L cells with temperature-sensitive mutants of reovirus type 3 and clones derived from reovirus type 1 (5, s-10). Virus was purified by using cesium chloride gradient centrifugation as previously described (8) and contained 100 particles per plaque-forming unit (PFU). Lymphocyte preparation. Murine lymphocytes were prepared from various organs of 2-to 4-month-old BALB/c mice of either sex as previously described (11). Red blood cells were lysed by adding Tris-buffered 0.76% NH4C1 and warming to 37 C for 10 min. Macrophages were removed by adherence to plastic Petri dishes. Splenocytes, lymph node cells, or thymocytes were pooled from two animals for each experiment. For the study of lymph node cells, inguinal and axillary lymph