Tumor-specific cellular immune responses were induced following vaccination. Cryopreserved prevaccine and postvaccine PBMCs were cultured in either medium alone, or with sCD40Lt activated autologous tumor cells in the presence or absence of HLA class I and class II blocking antibodies or their respective isotype control antibodies or sCD40Lt activated autologous normal B cells or autologous or irrelevant idiotype protein and cytokine production was detected by ELISA or ELISPOT as previously described.^6,12–14  Cytokine production in the supernatants for IFN-γ (A, D), GM-CSF (B, D), and TNF-α (C) was measured by ELISA. (D) Representative data on the cytokine production in response to autologous tumor cells from PBMC samples obtained at various time points in patient 3. (E) Tumor-reactive immune responses in postvaccine PBMC were associated with both HLA class I and class II molecules. IFN-γ production is shown for patients 1, 3, 5, and 6, and TNF-α production is shown for patient 9. (F) Significantly increased numbers of IFN-γ spots were detected by ELISPOT in response to autologous tumor cells but not in response to autologous normal B cells in 3 patients (P < .05). (G) Significantly increased numbers of Granzyme B spots were detected by ELISPOT in response to autologous tumor cells in postvaccine but not prevaccine PBMC samples (P < .05). (H) Postvaccine but not prevaccine PBMC from patient 5 produced significant amounts of cytokines in response to autologous idiotype protein compared with control isotype-matched irrelevant idiotype protein. (I) Induction of complete remission following vaccination. Vaccination time points are indicated by arrows. The sum of the product of the perpendicular diameters of 4 separate lymph nodes measured on CT scans is represented on the y-axis. PR - partial response; CRu - complete response, unconfirmed; CR - complete response.