T cell responses to ovarian tumor vaccines: identification and significance for future immunotherapy

The cellular immune responses to ovarian cancer patients treated with viral oncolysates (VO) ovarian tumor vaccines to vaccines are described. CD3+ cells proliferated after stimulation with the tumor vaccines in a dose-dependent manner. The proliferation of CD3+ cells stimulated with the tumor vaccine was blocked by anti-HLA-DR monoclonal antibody and anti-CD4 mAb indicating that CD3+ CD4+ cells from the blood of the patients treated with VO recognize tumor derived determinants in conjunction with MHC class II antigens. The regulatory activity of the T cells collected after VO treatment was assayed by co-cultivation with PBMC collected before VO treatment. These cells demonstrated increased helper activity for immunoglobin production by cells collected before vaccination and secreted IL-2 in response to stimulation by vaccine. Finally, when biochemical fractionation of the components of VO was attempted, PBMC from VO treated patients responded by proliferation to several fractions suggesting that they recognize multiple epitopes in the ovarian tumor vaccine. Therefore, these data provide novel evidence for the involvement of the T cells in response to ovarian tumor vaccines.