FIG. 2.

Cytolytic activity in the MLN and CLN. CBA mice were infected intranasally with 2 × 10⁶ PFU of KyA. On days 3, 5, and 7 p.i., the MLN and CLN were removed, a single-cell suspension was obtained, and the resulting LN cells were cultured for 3 days as described in Materials and Methods. Cytolytic activity was measured in a standard 4-h ⁵¹Cr release assay using mock-infected (▵) or KyA-infected (⧫) L-M fibroblasts as targets. Each effector-to-target (E:T) ratio was assayed in triplicate. The spontaneous release never exceeded 20%, and the variability between the values of specific lysis of triplicate cultures did not exceed 5%.