By using DNA electrophoresis and propidium iodide(PI) staining flow cytometry(FACS) analysis, we studied the mechanisms of lymphokine-activated killer(LAK) cell-mediated cytotoxicity. In the presence of pokeweed mitog...By using DNA electrophoresis and propidium iodide(PI) staining flow cytometry(FACS) analysis, we studied the mechanisms of lymphokine-activated killer(LAK) cell-mediated cytotoxicity. In the presence of pokeweed mitogen(PWM), human LAK cells induced DNA fragmentation of two leukemic cell lines(U937 cells and Raji cells) and two solid tumor cell lines(SW1116 cells and Hep-2 cells), a hallmark of apoptosis. The reactions were carried out at the effector/target ratio of 1:1 in 4h co-culture. Pretreatment with RNA and protein synthesis inhibitors(actinomycin D and cyclo hexamide) did not prevent the target cells from apoptosis.As the TNF-resistant tumor cell lines such as SW1116 cells and Raji cells were also triggered to apoptosis, other factors than TNF may play the role. DNA-PI staining FACS analysis also suggested that a part of LAK cells underwent apoptosis to some extent during incubation with target cells. The results provide a new way to investigate the mechanisms of the cytotoxicity of LAK cells, and a new possibility to enhance the efficiency of adoptive tumor therapy with LAK cells.展开更多
In view of increasing lead pollution(Pb^(2+)) of coastal waters, the compensatory abilities of holothurians need to be assessed. The goal of the work is to clarify the functional and phenotypical differences between t...In view of increasing lead pollution(Pb^(2+)) of coastal waters, the compensatory abilities of holothurians need to be assessed. The goal of the work is to clarify the functional and phenotypical differences between two types of phagocytes(P1 and P2) in Eupentacta fraudatrix exposed to Pb(NO_3)_2. It has been shown that 2 mg L^(-1) lead exposure for 48 h increases the number of P2 phagocytes as compared to P1 cells, does not significantly affect cell viability in both P1 and P2 phagocyte fractions, and significantly enhances chromatin condensation in P2 but not in P1 phagocytes. A lead concentration of 4 mg L^(-1) increases the number of P1 phagocytes compared to that of P2 type, and does not change cell viability and chromatin condensation in P1 phagocytes. In the P2 type, it decreases cell viability and does not influence the level of apoptosis. The protection against lead-induced apoptosis is apparently mediated by the activities of antioxidant enzymes, especially glutathione S-transferase. The differences in labeling cell surface receptors of P1 and P2 phagocytes by plant lectins also indicate the specific phenotypic properties of these cells. The results clarify the potential and GSH-dependent mechanisms of immune adaptation in holothurians that have been shortly exposed to lead at concentrations close to the maximum environmentally relevant level in coastal waters. Additionally, P1 and P2 phagocytes are first shown to have different functions and phenotypes during the response to lead, which indicates the complexity of the phagocytic system in holothurians and contributes to understanding the immunity evolution.展开更多
文摘By using DNA electrophoresis and propidium iodide(PI) staining flow cytometry(FACS) analysis, we studied the mechanisms of lymphokine-activated killer(LAK) cell-mediated cytotoxicity. In the presence of pokeweed mitogen(PWM), human LAK cells induced DNA fragmentation of two leukemic cell lines(U937 cells and Raji cells) and two solid tumor cell lines(SW1116 cells and Hep-2 cells), a hallmark of apoptosis. The reactions were carried out at the effector/target ratio of 1:1 in 4h co-culture. Pretreatment with RNA and protein synthesis inhibitors(actinomycin D and cyclo hexamide) did not prevent the target cells from apoptosis.As the TNF-resistant tumor cell lines such as SW1116 cells and Raji cells were also triggered to apoptosis, other factors than TNF may play the role. DNA-PI staining FACS analysis also suggested that a part of LAK cells underwent apoptosis to some extent during incubation with target cells. The results provide a new way to investigate the mechanisms of the cytotoxicity of LAK cells, and a new possibility to enhance the efficiency of adoptive tumor therapy with LAK cells.
文摘In view of increasing lead pollution(Pb^(2+)) of coastal waters, the compensatory abilities of holothurians need to be assessed. The goal of the work is to clarify the functional and phenotypical differences between two types of phagocytes(P1 and P2) in Eupentacta fraudatrix exposed to Pb(NO_3)_2. It has been shown that 2 mg L^(-1) lead exposure for 48 h increases the number of P2 phagocytes as compared to P1 cells, does not significantly affect cell viability in both P1 and P2 phagocyte fractions, and significantly enhances chromatin condensation in P2 but not in P1 phagocytes. A lead concentration of 4 mg L^(-1) increases the number of P1 phagocytes compared to that of P2 type, and does not change cell viability and chromatin condensation in P1 phagocytes. In the P2 type, it decreases cell viability and does not influence the level of apoptosis. The protection against lead-induced apoptosis is apparently mediated by the activities of antioxidant enzymes, especially glutathione S-transferase. The differences in labeling cell surface receptors of P1 and P2 phagocytes by plant lectins also indicate the specific phenotypic properties of these cells. The results clarify the potential and GSH-dependent mechanisms of immune adaptation in holothurians that have been shortly exposed to lead at concentrations close to the maximum environmentally relevant level in coastal waters. Additionally, P1 and P2 phagocytes are first shown to have different functions and phenotypes during the response to lead, which indicates the complexity of the phagocytic system in holothurians and contributes to understanding the immunity evolution.
