Binding of human lymphotoxin to target-cell membranes and its relation to cell-mediated cytodestruction

Salivary cytokines in healthy adolescent girls: Intercorrelations, stability, and associations with serum cytokines, age, and pubertal stage

Theoretically, the measurement of cytokines in saliva may have utility for studies of brain, behavior, and immunity in youth. Cytokines in saliva and serum were analyzed across three annual assessments in healthy adolescent girls (N = 114, 11-17 years at enrollment). Samples were assayed for GM-CSF, IFNγ, IL-1β, IL-2, IL-6, IL-8, IL-10, IL-12p70, TNFα, adiponectin, and cotinine. Results revealed: (1) cytokine levels, except IFNγ and IL-10, were detectable in saliva, and salivary levels, except IL-8 and IL-1β, were lower than serum levels; (2) salivary cytokine levels were lower in older girls and positively associated with adiponectin; (3) compared to serum levels, the correlations between salivary cytokines were higher, but salivary cytokines were less stable across years; and (4) except for IL-1β, there were no significant serum-saliva associations. Variation in basal salivary cytokine levels in healthy adolescent girls reflect compartmentalized activity of the oral mucosal immune system, rather than systemic cytokine activity.

In vitro cell-mediated and complement-mediated cytotoxicity to murine testicular cells

Male BALB/c mice at 8 to 14 weeks of age were divided into three groups: group 1 was immunized with an emulsion of testicular cells (TCs) (10(7)/mouse), complete Freund's adjuvant (CFA), and extract of Bordetella pertussis (BP); group 2 was given CFA and BP injections; and group 3 was given sterile saline injections. Suspensions of TCs and spleen cells (SCs) from each mouse were prepared 4 weeks after the first immunization for a cytotoxic T lymphocyte (CTL) assay. For the antibody-dependent cell-mediated cytotoxicity (ADCC) and antibody-dependent complement-mediated cytotoxicity (ACC) assays, TCs and SCs were prepared from normal male and female mice, respectively. Targets were labeled with Na251 Cr0(4). The interactions of targets (TCs) and effectors (SCs) were conducted at 32.5 degrees C (for CTL, ADCC, and ACC assays) or 37 degrees C (for ACC assay). In the CTL assay, SCs from group 1 and group 2 caused significantly more killing than those from group 3. Specific cytotoxicity in the ADCC assay was only detected in the serum (maximum specific lysis 47.65%) of one mouse. No other cytotoxicity was detectable in 61 serum samples from group 1 (n = 25), group 2 (n = 17), and group 3 (n = 19). In the ACC assay, no significant specific cytolysis was found at different incubation temperatures (32.5 and 37.0 degrees C) in 44 serum samples from the three groups. These results suggest that CTLs are important in the pathogenesis of experimental allergic orchitis (EAO). Adjuvant alone, probably because of breakdown of the blood-testis barrier, causes significant T lymphocyte cytotoxicity to TCs.(ABSTRACT TRUNCATED AT 250 WORDS)

DNA fragmentation: manifestation of target cell destruction mediated by cytotoxic T-cell lines, lymphotoxin-secreting helper T-cell clones, and cell-free lymphotoxin-containing supernatant

A Lyt-2+, trinitrophenyl-specific, lymphotoxin-secreting, cytotoxic T-cell line, PCl 55, mediates the digestion of target cell DNA into discretely sized fragments. This phenomenon manifests itself within 30 min after effector cell encounter as measured by the release of 3H counts from target cells prelabeled with [3H]deoxythymidine and occurs even at very low effector to target cell ratios (0.25:1). A Lyt-1+, ovalbumin-specific, lymphotoxin-secreting T-helper cell clone, 5.9.24, is also able to mediate fragmentation of target cell DNA over a time course essentially indistinguishable from the cytotoxic T lymphocyte-mediated hit. Cell-free lymphotoxin-containing supernatants also cause release of DNA from targets, although they require a longer time course, on the order of 24 hr. In contrast, lysis of cells by antibody plus complement or Triton X-100 does not result in DNA release even after extended periods of incubation (24 hr). All three treatments that result in the release of DNA from cells cause fragmentation of that DNA into discretely sized pieces that are multiples of 200 base pairs. The results thus suggest that cytotoxic T cells, lymphotoxin-secreting helper clones with cytolytic activity, and lymphotoxin all effect target cell destruction by means of a similar mechanism and that observed differences in time course and the absence of target cell specificity in killing mediated by lymphotoxin may simply reflect differences in the mode of toxin delivery.

Dysfunction of the sarcoplasmic reticulum in polymyositis

The transport of calcium in vesicles of sarcoplasmic reticulum isolated from muscle specimens from 6 patients with early, active polymyositis and from 11 controls was examined. The time courses of calcium uptake and calcium-dependent ATPase activity were measured simultaneously. Calcium uptake by sarcoplasmic reticulum vesicles from patients with polymyositis was 50% less than that by vesicles from controls (P less than 0.001). In contrast, no difference in calcium-dependent ATPase activity was noted between vesicles from patients with polymyositis and controls. The demonstrated defect may be important in the pathogenesis of muscle weakness in polymyositis.

Rabbit tumor necrosis factor: mechanism of action

Rabbit tumor necrosis factor (TNF) was examined for effects on normal and transformed cells in culture. Several assays for killing of L-929 cell targets were developed, and their sensitivities were compared. Normal cells were not killed by TNF, and the discrimination between normal and transformed cells was shown not to be due to a cell cycle-dependent mechanism. TNF killing of L-929 cells was delayed for 10 to 12 h and thereafter showed concentration and time-dependent increases in cytolysis. Actinomycin D or cycloheximide treatment of L-929 cells resulted in an enhancement of the rate of cell killing as well as a shortening of the preceding lag period. TNF killing of L-929 cells was temperature dependent; cells were considerably more resistant to lysis at 25 degrees C and showed enhanced killing at 39 degrees C as compared to 37 degrees C controls. The slope of the dose curve showed less than single-hit kinetics. A model for cell killing whose general features incorporate both the specificity and catalytic properties of an enzymatic reaction is proposed for TNF action.

Characterization of lectin-induced cellular cytotoxicity mediated by mouse spleen cells and the role of lymphotoxin

The cellular cytotoxicity mediated by mouse spleen cells in the presence of mitogenic or non-mitogenic lectins was established under serum-free conditions and characterized. Compared with the lectin-induced cellular cytotoxicity (LICC) in the guinea-pig, the activity of lymphotoxin (LT) released into the murine LICC assay cultures was very low. However, a positive correlation was found between the strength of LICC and the LT activity released into the supernatants. Moreover, the addition of puromycin, a potent enhancing reagent of guinea-pig LT activity, markedly promoted the LICC when added 4 h after the initiation of the LICC culture. These data, taken together, suggest that LT acts as an effector molecule in the murine LICC systems as well as in the guinea-pig LICC systems. Properties of the effector cell populations mediating LICC were investigated by depletion of plastic-adherent or nylon-wool adherent cells, by treatment of spleen cells with anti-T-cell sera and complement, and by use of nude mouse spleen cells. The results obtained suggest that both concanavalin A and phytohaemagglutinin-P can induce nylon-wool non-adherent T-cell mediated LICC, phytohaemagglutinin-W was found to be capable of inducing both the nylon-wool non-adherent T-cell mediated LICC and the nylon-wool adherent non-T-cell mediated LICC, the major effector of Bauhinia purpurea agglutinin-LICC was found to be the nylon-adherent non-T-cell population.

Ultrastructural changes of cultured human amnion cells by Clostridiu difficile toxin

The ultrastructure of the surface of primary human amnion monolayer cells undergoing cytopathology induced by Clostridium difficile toxin was examined by scanning electron microscopy. Our observations indicated that the type and distribution of cell surface projections were altered dramatically by this toxin. The patterns of such surface changes were specific for the two different types of cells found in this cell culture. Cells with demarcated borders showed rearrangement of microvilli into globular chains or ridges which lined up with the branching membrane. Cells without demarcated borders exhibited studlike microvilli, all arranged into ridges or globular chains. These changes were noted after 1 h of toxin exposure and persisted without further progression, in spite of continued toxin exposure, up to 48 h. These data indicate that C. difficile produces a cytolytic toxin and that scanning electron microscopy may be useful in determining toxin-cell interactions.

Target cell - substratum interaction. I. Effect of primed lymphocytes on a rat mammary adenocarcinoma tumor cell line

The differential effects of normal and immunologically primed lymphocytes on the adherence of trypsinized rat mammary adenocarcinoma tumor cells (DMBA"8) to their substratum are described, utilizing both allogeneically and syngeneically primed lymphoid cells as effectors. This observation may illustrate an important immunological phenomenon, and may result in a simplified assay procedure for the detection of cell-mediated immunity.

Tumor cell phagocytosis and cytotoxicity of lymphoblastoid cells following concanavalin A treatment

Cell-to-cell interaction was investigated in various malignant tumor cells (human ovarial tumor, lung cancer, carcinoma of larynx and hamster melanoma cell) and in human lymphoblastoid cells (T-cell (MOLT-4 cell), thymoma cells and B-cells (Burkitt lymphoma cell)). Live lymphoblastoid cells did not adhere to the cell surfaces of tumor cells nor the lymphoblastoid cells were ingested by tumor cells without immunologic and specific treatment. Tumor cells as well as T-cells and B-cells had receptors to concanavalin A on their surfaces, and they showed marked cell binding of tumor cells and lymphoblastoid cells. Moreover, tumor cells that phagocytized lymphoblasts underwent marked cell destruction within 4 hours of cell binding. The cytolytic mechanism of the target tumor cell was probably related to contact with the lymphoblastoid cells and was increased by ingestive activity, and metabolic disturbance by lymphotoxin in tumor cells.

Phagocytosis of lymphoblastoid cells and cell destruction of human malignant tumor cells

On the basis of the previous study, on the cell interaction between malignant tumor cells and other cells, especially with lymphocytes, the present study was carried out by investigating cell to cell interaction of human malignant tumor cells and human lymphoblastoid cells such as T-cell (MOLT-4 cell) and B-cell (Burkitt lymphoma cell). As a result it has been revealed that live lymphoblastoid cells were not adhered on the cell surface of the tumor cells, nor is it ingested by tumor cells, but in thepresence of HVJ (Sendai virus: 2,000 H.A. units) it adheres slightly on the cell surface of tumor cell but no cell fusion of tumor cells and lymphoblastoid cells is observable. On the other hand, the tumor cell as well as T-cell and B-cell all have receptors to concanavalin A (Con. A) on their cell surfaces, and they show a marked cell binding such as tumor cell and T-cell, tumor cell and B-cell, and there can be observed a marked phagocytosis of lymphoblastoid cells by tumor cells. Moreover, the tumor cells that have phagocytized lymphoblastoid cells undergo a marked cell destruction within 4 hours of cell-binding and phagocytosis, which is especially prominent in the case of phagocytosis of E.B cell by tumor cell.