Natural killer (NK) cells, effector lymphocytes of natural cytolytic activity, are critical in the defense against infection. In HIV-1 infection, a decrease in NK cytolytic activity has been described ; the mechanisms involved, though, are not known. The purpose of this study was to investigate the natural killer cell activity (NKCA) and the in vitro action of immunomodulators in an intent to account for this deficiency. 20 HIV-1-infected subjects (15 males and 5 females, mean age = 36) and 30 seronegative controls were analyzed. NKCA was determined by using K-562 cells radiolabeled with 51Cr (sodium chromate) as target cells, and peripheral mononuclear cells as effector cells, the results being expressed as specific lysis percentage. The effect of the immunomodulators: interleukin-2 (IL-2, 25 U/ml), interferon-alpha (IFNa-, 500 U/ml), and the mixture of the calcium ionophore (A23187, 10.0 uM) plus a phorbolester (TPA, 250 ng/ml) (lo + TPA) was analyzed in in vitro cultures. Phenotype analysis, CD16/56+, was performed by flow cytometry with fluorescent monoclonal Ab (Becton Dickison).
According to our results , a significant NKCA decrease is observed in the patients compared with controls.
This low activity was not affected by immunomodulators IL-2 and IFN-a, but significant lo+ TPAmediated
enhancement was observed. This would indicate that the initial activation mechanisms of these cells would be altered in HIV-1 infection, a situation similar to the one observed in other immunodeficiencies and in severe pathologie s such as polytrauma and sepsis. It is important to try to understand these mechanisms in relation to possible immunological therapies.
Sepúlveda C, C. ., Puente P., J. ., & Weinstein O., C. . (1997). Citólisis natural en sujetos infectados por vih-1. Alteración de la activación de las células natural killer. Revista Hospital Clínico Universidad De Chile, 8(2), pp. 101–9. https://doi.org/10.5354/2735-7996.1997.81421
