RESUMEN
We have examined the effect of human alpha-fetoprotein (h-alpha FP), at concentrations ranging from the physiological to pathological circulating levels, on the native and alpha IFN- and IL2-boosted NK activity of normal peripheral blood lymphocytes (PBL). The cytotoxic function of unstimulated PBL was unchanged after a 16 hr incubation with 200 to 8000 ng/ml h-alpha FP. By contrast, this treatment significantly reduced the responsiveness of PBL to the NK-enhancer factors IFN and Interleukin 2. Optimal inhibition was observed when cells were pre-incubated with h-alpha FP before being stimulated with IFN. The sensitivity of PBL to the h-alpha FP mediated inhibition was restricted to the very early times (30 min) of incubation with the stimulating agents.
Asunto(s)
Células Asesinas Naturales/efectos de los fármacos , alfa-Fetoproteínas/farmacología , Citotoxicidad Inmunológica/efectos de los fármacos , Humanos , Técnicas In Vitro , Interferón-alfa/farmacología , Interleucina-2/farmacología , Células Asesinas Naturales/inmunología , Cinética , alfa-Fetoproteínas/inmunologíaRESUMEN
The findings of alpha fetoprotein antigens are reported in raw extracts of Entamoeba histolytica and also, on the membranes of trophozoites obtained from an axenic culture medium. This was confirmed through two techniques: Ouchterlony's immunodiffusion and indirect immunofluorescence using an antialpha fetoprotein rabbit antiserum. Previously, it was shown that this last antiserum did not recognize antigens of bovine albumin. The presence of alpha fetoprotein antigens in E. histolytica suggest that they may be a product of the metabolism of the ameba and that their concentration and localization might have a biological significance. Those antigens may appear because enzymes of the ameba degrade the bovine albumin from the culture medium. It is proposed that in the host with invasive amebiasis, alpha fetoprotein could also be found around E. histolytica and thus, inhibit the reactivity of the lymphocytes that attempt to attack it. In this manner, the capacity of ameba to form alpha feto protein would be an important mechanism in the relationship host--parasite.