Inducement of Specific CTLs by Antigen-Peptides from Human Leukemia Cells and Their Cytotoxicity to Leukemia Cells

To investigate the inducement of cytotoxic T lym phocytes(CTL s) by antigen peptides m ixture from different leukemia cells and the cross- reaction of the m ixtures from different cell lines,antigen peptides m ixtures were prepared from different leukemia cell lines respectively and then bound with Hsp70 in vitro.Activation and proliferation of PBMC were observed after stim u- lation with different Hsp70 - peptide complexes.The ratio of CD8+ in proliferative cells was ana- lyzed by flow cytometry.The cytotoxicity of the activated PBMC to different target cells was as- sayed.The results showed that the antigen peptides from different leukemia cell lines,bound with Hsp70 ,could activate PBMC effectively,and stimulate the activated PBMC to proliferate.The proliferative PBMC had specific cytotoxicity to corresponding leukem ia cells.CD8+ cells,account- ing for a high proportion in proliferative cells,had a specific cytotoxicity to leukemia cells from which antigen peptides were prepared,suggesting that these CD8+ cells were CTL s specific to leukemia cells.CTL s activated by Hut78- peptides or Molt4 - peptides had a significantly stronger cytotoxicity to Hut78cells,Molt4 cells and Jurkat cells than that of CTL s activated by HL - 6 0 - peptides(P<0 .0 5 ) .And the cytotoxicity of CTL s activated by Hut78/ Molt4 - peptides to Jurkat cells was significantly stronger than that of CTL s activated by either Hut78- peptides or Molt4 - peptides alone(P<0 .0 5 ) .It is concluded that antigen peptides m ixtures from leukem ia cells can induce specific antitumor CTL s.There exists cross- reactivity among antigen peptides m ixtures from different cell lines of the sam e type leukemia and more cross- reactive antigen peptides could be obtained from m ore cell lines,suggesting that antigen peptides m ixture with broad antigenic spectrum could be prepared by using multiple leukemia cell lines.

INVESTIGATION OF INDUCING EFFECT OF SPECIFIC CYTOTOXICITY OF CTLS BY ANTIGEN PEPTIDES FROM T LYMPHOCYTIC LEUKEMIA CELLS

Objective: To investigate the characteristics of specific antitumor immunity induced by antigen peptides mixture from T lymphocytic leukemia cells. Method: Antigen peptides mixtures were prepared from different leukemia cell lines and then bound with Hsp70 in vitro. Human peripheral blood mononuclear cells (PBMC) were cultured in vitro, and activated with Hsp70-antigen peptides. The activated PBMC was cultured continuously in vitro, and used as effector cells in vitro test of cytotoxicity to different target cells. Results: The antigen peptides from different leukemia cell lines were peptides mixture and could activate PBMC effectively if they were presented by Hsp70. The activated PBMC could proliferate in the presence of IL-2 and Hsp70-antigen peptides. The proliferative PBMC had specific cytotoxicity to leukemia cells corresponding to the antigen peptides. PBMC activated by antigen peptides from T lymphocytic leukemia cell lines could effectively kill T lymphocytic leukemia cells, and the cytotoxicity of these PBMC to T lymphocytic leukemia cells was significantly stronger than that of PBMC activated by antigen peptides from other leukemia cells (P < 0.05). PBMC activated by either Hut78-peptides or Molt 4-peptides could effectively kill Jurkat cells. And the cytotoxicity of PBMC activated by Hut78/Molt-4-peptides to Jurkat cells was significantly stronger than that of PBMC activated by either Hut78-peptides or Molt-4-peptides alone (P<0.05). Conclusion: Antigen peptides mixture from T lymphocytic leukemia cell lines can induce specific cytotoxic effect to T lymphocytic leukemia cells. There exists cross-reactivity among antigen peptides mixture from different T lymphocytic leukemia cell lines. The cross-reactivity could be amplified by blending of different antigen peptides from different T lymphocytic leukemia cell lines, suggesting that it is possible to prepare broad-spectrum antigen peptide vaccine against T lymphocytic leukemia by using multiple leukemia cell lines.