Zinc has important effects on structural and functional activities of many proteins and enzymes involved in biological activities specially regulation of immune system. Deficiencies of this element may result in many disease and immunological disorders.

          This study was carried out to examine the in vitro effects of different cncentration of Zinc on viability and cell death of T-Lymphoid(Molt-4) cell line. In this study the cell line was exposed to different concenteration of Zinc (10nM to 500µM)followed by incubation (37 c, 5%Co2) at periods durations (0 - 72 h). The cells were then evaluated with trypan blue exclusion dye, and light microscopy.

          The results of this study showed almost different responses to different amount of Zinc by The T cell line. less than 100µM of Zinc at different incubation time points had little to no effects on cell line when compared to the controls. higher concenterations of Zinc (>100µM)diminished cell viability to 70% at 12 hrs and less than 50% at 24 to 72 hrs of incubation times it can be concluded that Zinc shows cytotoxic effects (Molt-4)depending on the  
   concentrations used.

          At higher concenterations it exerts cytotoxic effects.