Efecto in vitro del suero de la trucha arco iris, oncorhynchus mykiss, sobre metacercarias del género tylodelphys trematoda displostomatidae / The in vitro effect of rainbow trout, oncorhynchus mykiss, serum in tylodelphys sp trematoda displostomatidae metacercariae

Here, it has been described that normal fresh sera from rainbow trout (oncorhynchus mykiss) were able to Iyse Tylodlphys sp. metacercariae isolated form Galaxias maculatus (Jenyns, 1842) (Teleostei, Galaxiidae) brain. This effect was time dependent, and progressively increased since 1 h up to 18 h incubation. There were oscillations in the ability of different sera samples to lyse these parasites. Similar values were achieved with other salmonid sera, and also with normal human sera pool. The lytic activity was abolished by heat-inactivated sera, by zymosan treatment and by incubation in the presence of EDTA. However, the mean values obtained in the presence of EGTA-Mg++ did not significantly differ from those found with sera as a source of complement. The results of this study suggested the role of complement alternative pathway on Tylodephys sp. in vitro lysis, under our experimental conditions

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. Since interleukin 2 (IL-2) is able to enhance NK levels, we analized the capacity of this lymphokine to reverse the effect of He HIV+ sera. We found that when IL-2 activation of NK activity occurred simultaneously or after HIV+ serum-treatment, a significant restoration of NK function was observed. In contrast, preincubation with IL-2 did not affect the inhibitory effect exerted by HIV+ sera.

Actividad citotóxica "Natural Killer" en pacientes con hemofilia / Natural Killer cytotoxic activity in hemophilic patients

This work attempats to clarify the mechanisms to functional impairment of natural killer activity in individuals with acquired immune deficiency syndrome (AIDS) and those at high risk of developing AIDS (R-AIDS). We examined the effect pf lymphokine rich supernatants (SN) on effector cells from these individuals. Mononuclear cells (CM) from R-AIDS were more susceptible to stimulation with these SN. When we studied the role of different T lymphocytes subsets in the regulation of NK activity, the results indicate that the effect of SN was the combination of opposite effects. We also studied the ability of CM from patients with Hemophilia (He) to incresase NK cytotoxicity upon stimulation with physiological and non physiological agents (IL-2,IFNa and y, Poly I:Cor PMA). The response was impaired in HIV+, especially in HIV+ with symptoms. Our results also demonstrate that NK cells with slight lytic activity (Leu7 + CD16 -) predominated in HIV+. On the other hand, the ocurrence of IL-2 receptor positive cells was similarly high in both HIV+and HIV- individuals compared to N controls. Analysis of NK activity in several individuals studied after a 2-year period revealed that this function was deteriorated with disease progression. The effect of positive or negative sera for the HIV from. He on normal NK activity was analyzed. We showd that sera from He interfered with normal NK activity. The inhibitory effect found, was higher in HIV+ sera and increased as HIV disease progressed. When the same concentration of DEAE-purified IgG was used, we found that HIV+ AIDS IgG was more inhibitory than the others