Axillary lymph node (LN) cellular immune response to Her-2/neu peptides in patients with carcinoma of the breast

The HER-2 peptide G89 (777-789) was recently shown to induce proliferative responses by peripheral CD4+ T cells in breast cancer patients. To investigate potential differences in the local cellular immune response in breast cancer patients with (Mets+) and without (Mets-) axillary LN metastases, lymphocytes were isolated from axillary LNs from patients with breast cancer and proliferative and cytokine response to G89 were determined. Four women were treated preoperatively with adriamycin-based chemotherapy. Freshly isolated lymphocytes from LNs of seven women with invasive breast cancer were stimulated with 15 uM G89 and G90 (886-898, control HER-2 peptide) and other control antigens. [3H] thymidine incorporation was determined 4 days later. IFN-g, IL-4, and IL-10 levels were determined at priming or at restimulation with 089 and G90 using cytokine specific double sandwitch-ELISA kits with a sensitivity of 10 pg/ml. Differences between groups were compared using the Student t-test. Three of six Mets(+) LNs showed a 3-4 fold higher proliferative response to G89 compared with unstimulated cells from the same LN (P<0.05). Three of four Mets(-) LNs also responded to G89 indicating the presence of prior G89 sensitized and non-tolerized T cells. In one patient where there was no proliferation with G89. the ratio of Ifn- to IL-4 levels in response to G89 was > 5 compared with G90 which yielded a ratio of <0.5. In two patients where Mets(+) and Mets(-) LNs were analyzed in parallel, the IFNg: IL-4 ratio was 3-4 fold lower in Mets(+) LNs compared with Mets(-) LNs. Mets(+) LNs from two of the four patients who had preoperative chemotherapy responded to G89 by proliferation. These results indicate that G89 can activate LN T cells from women with invasive breast cancer. This activation is associated with a predominately TH1 cytokine response and therefore suggests that conditioning with G89 may be of value in breast cancer vaccine development. Ongoing studies are addressing the ability of G89 to provide help for tumor-specific CTL induction and survival.