Identification, Isolation and Characterization of Foxp3+ CD25+CD4+ Tumor Infiltrating Lymphocytes from Cervical and Ovarian Cancer

Despite infiltration by CD4+ and CD8+ lymphocytes tumors grow progressively and are not eradicated by the immune system. In cervical cancer antigen specificity of tumor infiltrating lymphocytes (TIL) to HPV antigens has been demonstrated. Upon isolation from the tumor and in vitro culture such TIL display lytic activity against antigen positive target cells, or respond with cytokine secretion. Therefore, local immune suppression in situ is a critical problem. Immunosuppressive regulatory T cells are characterized by expression of transcription factor Foxp3. We have identified and quantified Foxp3+ cells in tumor biopsies from cervical cancer (CxCa) and ovarian cancer (OvCa). From adjacent tissue samples TIL were isolated by short term culture and phenotypes characterized by flow cytometry. From a consecutive series of 9 cervical cancers and 4 ovarian cancers short term TIL lines were established. TIL consisted of CD4 (OvCa: 29.1% [4.11–89.53], CxCa: 39.82 [8.6–83.56]) and CD8 (OvCa: 6.65 [1.04–15.53], CxCa: 31.26 [7.23–71.18]) lymphocytes. TIL were CD45RO+ (OvCa: 38.53% [4.44–94.64], CxCa: 57.35 [30.27–77.65]) and did not display an activated phenotype of CD69+/CD45RO+ (OvCa: 0.65% [0.4–1.17], CxCa: 1.27% [0.19–2.17]). All TIL lines contained Foxp3+/CD4+ T cells (OvCa: 1.8% [0.27–4.57], CxCa: 4.64% [0.33–12.74]). There were low and comparable numbers of NK cells detected (OvCa: 0.7% [0.31–1.41], CxCa: 0.64 [0.04–2.29]). There is a trend for higher numbers of regulatory T cells in cervical cancer in situ and in isolated TIL. The putative antigen specificity of Foxp3+ T cells to HPV antigens is currently being analyzed.