title: Cytotoxic activity of CD4+ T cells against autologous tumor cells.
abstract: The 51Cr-release assay is mostly applied to detecting the cytotoxic activity of CD8+ T cells, and little is known about the activity of CD4+ T cells. Therefore, the correlation between the cytotoxic activity of CD4+ or CD8+ T cells and the incubation period with autologous tumor cells was analyzed by two methods. The incubation periods were 4 and 20 h (4 h and 20 h assay) for the 51Cr-release assay. Eight pairs of tumor cells and T cells were assayed. T cells were fractionated into CD4+ and CD8+ T cells by using magnetic beads and panning methods, and those cells were activated by culture with recombinant interleukin-2 and immobilized anti-CD3 monoclonal antibody. In 6 out of 8 cases, no cytotoxic activity of CD4+ T cells was detected by the 4 h assay, whereas cytotoxic activity was detected in all cases in the 20 h assay. The cytotoxic activities in 20 h assay of CD4+ T cells were increased 67-fold in comparison with the activities in 4 h assay (range: 5-197). In the case of CD8+ T cells, cytotoxic activities were detected in 6 out of 8 cases in the 4 h assay. The lytic unit ratio of CD4+ and CD8+ T cells was calculated as 1.5 in the 20 h assay (range: 0.2- > 7.2) versus 0.4 in the 4 h assay (range: < 0.1-1.3). Cytotoxic activities in colorimetric assay using Crystal Violet with a 24 h incubation were similar to those in the 20 h 51Cr-release assay in all eight cases. These results indicate that CD4+ T cells have cytotoxic activity as strong as that of CD8+ T cells towards autologous tumor cells.
authors.affiliation: RI Laboratory, National Cancer Center Research Institute, Tokyo.
authors.forename: Y
authors.initials: Y
authors.lastname: Konomi
authors.forename: T
authors.initials: T
authors.lastname: Sekine
authors.forename: T
authors.initials: T
authors.lastname: Takayama
authors.forename: M
authors.initials: M
authors.lastname: Fuji
authors.forename: T
authors.initials: T
authors.lastname: Tanaka
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016516:CD4-CD8 Ratio; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology; D002857:Chromium / Q000493:pharmacokinetics; D002860:Chromium Radioisotopes; D003124:Colorimetry; D003602:Cytotoxicity, Immunologic; D005260:Female; D005840:Gentian Violet; D006801:Humans; D016219:Immunotherapy, Adoptive; D016246:Lymphocytes, Tumor-Infiltrating / Q000166:cytology / Q000276:immunology; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000276:immunology / Q000378:metabolism / Q000473:pathology / Q000628:therapy*
chemical_list: D002860:Chromium Radioisotopes; D002857:Chromium; D005840:Gentian Violet