UA did not augment T-cell expansion or alter tumor-infiltrating leukocytes levels. (A) The levels of IL-4–secreting cells that responded to either ConA or tumor cell lysates. Splenocytes for the ELIspot assay were obtained from animals injected with tumor cells alone (▭), tumor cells with 25 μg UA (), and 25 μg UA alone (). Each bar represents the mean (± SEM) of 12 determinations. (B) The levels of IFN-γ–secreting T cells responding to no antigen, ConA, or neu-derived MHC class I peptide p420-429. Splenocytes were derived from animals that received dying tumor cells with various levels of UA. Each bar is the mean of 9 determinations. (C) The numbers of neu peptide p420-429 tetramer-positive T cells in draining nodes or splenocytes from mice depicted in panel F. Each is the mean (± SEM) of triplicate determinations calculated from 3 mice. (D,E) The frequencies of Oval(323)-specific CD4⁺DO11.10 T cells (D) and Oval(257)-specific CD8⁺OT-I T cells (E) as percentage of all CD3⁺ splenocytes in untreated control (Cont), ovalbumin cognate peptide/UA (UA), or cognate ovalbumin peptide/GM-CSF (GM). Each bar represents the mean (± SEM) of 7 replicates and represents 2 identical experiments, which yielded similar results. (F-L) The levels of various leukocytes in tumors from mice that received either no treatment (Cont) or pretreatment with tumor cells and 25 μg UA (T + UA), prior to tumor injection. Each bar is the mean (± SEM) of 3 replicates. Each graph represents a unique intratumoral leukocyte population from control, untreated mice and from mice pretreated with dying tumor cells containing UA. All are calculated from 100 000 total events. Results are expressed as the percentage of total cells, both tumor cells and leukocytes, collected following tumor mincing.