[In vitro effect of rainbow trout (Oncorhynchus mykiss) serum in Tylodelphys sp. (trematoda, Diplosromatidae) metacercariae].

Here, it has been described that normal fresh sera from rainbow trout (Oncorhynchus mykiss) were able to lyse Tylodelphys sp. metacercariae isolated from Galaxias maculatus (Jenyns, 1842) (Teleostei, Galaxiidae) brain. This effect was time dependent, and progressively increased since 1 h up to 18 h incubation.

Interleukin-2 restores natural killer activity inhibited by sera from HIV+ hemophilic patients.

Natural killer (NK) activity is impaired in patients with positive serology for the human immunodeficiency virus (HIV). We previously found an inhibitory effect of sera from hemophilic (He) HIV+ patients on normal NK activity. In the present study, we have further characterized this effect by studying its reversibility, temperature and time incubation dependence.

Inhibition of normal natural killer cytotoxicity by sera from hemophilic patients.

In this study we searched for circulating antibodies or other serum factors that could account for the natural killer (NK) defect observed in hemophiliacs (He) infected with the human immunodeficiency virus (HIV). We analyzed the effect of negative or positive sera for HIV from He on normal NK activity. We showed that sera from He interfered with normal NK cytotoxicity.

HIV infection and natural killer cytotoxicity in hemophilic patients.

In this study we analyzed the ability of peripheral blood mononuclear cells (PBMC) from hemophilic patients (He) with negative or positive serology for the human immunodeficiency virus (HIV), to increase natural killer (NK) cytotoxicity upon stimulation with physiological and non physiological agents. Purified interleukin-2 (IL-2), the interferon (IFN)-inducer polyinosinic polycytidylic acid (PIC), recombinant alpha- and gamma-IFN and the protein kinase activator phorbol myristate acetate (PMA) were used as stimulatory agents. The NK functional response was correlated with the presence of PBMC bearing phenotypic markers of activated cells (IL-2 receptor, IL-2R) and of different NK cell maturation stages.

Effect of lymphokines on natural killer cytotoxicity in patients with high risk of developing the acquired immune deficiency syndrome.

Regulation of natural killer (NK) activity of peripheral blood mononuclear cells (PBMC) from patients with the acquired immune deficiency syndrome (AIDS) and from individuals at high risk of developing AIDS (R-AIDS) was studied. The response of untreated PBMC to the interferon inducer polyinosinic polycytidilic acid (Poly I:C) was lower in AIDS and R-AIDS than in normal controls and PBMC from R-AIDS were more susceptible to stimulation with lymphokine rich supernatants (Con A-SN, PHA-SN, lectin free IL-2) than AIDS and normal controls. To determine the role of the different T lymphocyte subsets in the regulation of NK activity, PBMC were selectively treated with monoclonal non-cytotoxic anti-Leu 2a and anti-Leu 3a antibodies and then stimulated with lymphokine rich supernatants.

Immunomodulation exerted by cyclophosphamide is not interfered by N-acetyl cysteine.

Metabolism of cyclophosphamide (Cy) by liver enzymes results in cytostatic products and acrolein, which exerts urotoxicity. Experiments were designed to determine which metabolites are responsible for Cy-induced immunomodulation. For this purpose, mice were treated simultaneously with Cy and N-acetyl-cysteine (NAC), a thiol compound which reacts with acrolein, and different immunological functions were assayed.

Cyclophosphamide inhibits antibody-dependent cellular cytotoxicity (ADCC) suppression exerted by lymph node cells.

The effect of cyclophosphamide (Cy) on suppression of antibody-dependent cellular cytotoxicity (ADCC) by lymph node cells (LNC) was evaluated. The results show that the suppression of ADCC exerted by LNC was abrogated when mice had been treated with Cy. Moreover, it was shown that ADCC inhibition induced by LNC was mediated by soluble factor(s) and that treatment with a single dose of 200 mg/kg ip of Cy, significantly decreased its release.

Interleukin 2 is not sufficient for the continuous growth of cloned NK-like cytotoxic cell lines.

Interleukin 2 (IL 2) has been strongly implicated as the agent responsible for the continuous growth of T cell lines in vitro. In the present study we confirmed that IL 2 alone could support the growth of a widely used cytotoxic T cell line. In contrast, we found that IL 2 was not sufficient to support the long-term growth of cloned NK-like cytotoxic lymphocyte cell lines.

Interleukin 2 induces gamma-interferon production: participation of macrophages and NK-like cells.

Interleukin 2 (IL 2) has been shown to be a potent stimulator of natural killer (NK) cells. In the present studies, partially purified mouse and human IL 2 preparations were also found to induce interferon (IFN) from mouse spleen cells. By the criteria of sensitivity to treatment at pH 2 and failure to be neutralized by a potent anti-alpha, beta IFN serum, the species of IFN produced was of type gamma.

Phagocytosis of Trypanosoma cruzi by human polymorphonuclear leukocytes.

Phagocytosis of culture forms of Trypanosoma cruzi was assayed by a radioisotopic method. Purified polymorphonuclear leukocytes (PMN) were mixed with 3H-uridine-labeled T. cruzi epimastigotes in the presence or absence of anti-T.

Trypanosoma cruzi: sequence of phagocytosis and cytotoxicity by human polymorphonuclear leucocytes.

We have studied the relationship between phagocytosis and cytotoxicity of human polymorphonuclear leucocytes (PMN) to sensitized Trypanosoma cruzi. Assays were done simultaneously using [3H]-uridine labelled epimastigotes as target cells. Phagocytosis was evaluated by the uptake and cytotoxicity by the release of parasite associated [3H]-uridine.