[Cytotoxic activity of spleen lymphocytes in BALB/c mice immunized by HSP110-HER2/neu ICD]

To explore the cytotoxic responses of spleen T lymphocytes (CTL) in BALB/c mice induced by recombinant HSP110-HER2/neu ICD complex.

Tumor-bearing mouse model was immunized by HSP110-HER2/neu ICD complex. The IFN-γ level secreted by activated spleen T lymphocytes was detected by enzyme linked immunospot assay (ELISPOT). The corresponding CTL activity was measured by granzyme release assay.

The BALB/c mouse model of human mammary tumor highly expressing HER2/neu was established. HSP110-HER2/neu ICD complex immunization led to a significantly higher level of INF-γ than that in HSP110-P(789-797) immunized and HER2/neu ICD immunized mice. HSP110-HER2/neu ICD complex immunized animals also show significant CTL activity. The results of immunohistochemical staining showed that the number of blue spots in the PBS group was 4.57 ± 1.33, HSP110 group 6.83 ± 2.08, HER2/neu ICD group 16.17 ± 2.86, HSP110-P(789-797) group 43.67 ± 4.78, and SP110-HER2/neu ICD group 76.51 ± 8.17. The number of IFN-γ-secreting spleen lymphocytes in the HSP110-HER2/neu ICD group was significantly higher than that in the HSP110-P(789-797) group, and that of HSP110-P(789-797) group was significantly higher than that of HER2/neu ICD group (P < 0.01). The target cell-killing rate of the PBS group was (8.15 ± 1.27)%, HSP110 group (9.51 ± 1.51)%, HER2/neu ICD group (14.03 ± 2.45)%, HSP110-P(789-797) group (25.99 ± 3.04)% and HSP110-HER2/neu ICD group (38.15 ± 3.95)% (all P < 0.01).

HSP110-HER2/neu ICD complex can promote the proliferation and maturation of T lymphocytes into CTLs, and might be used as anti-tumor vaccine to induce potent cytotoxic T lymophocyte immunoresponse against specific tumor cells.