Abstract: Pyrrolizidine alkaloids(PAs) are widely distributed in plantae.Many PAs are hepatotoxic,Lung toxicity(carcinogenesis),neurotoxic and cytotoxic.
In addition, only certain murine mAb isotypes hae been shown to effectiely bind to and actiate elements of the human immune system, thereby triggering cytotoxic effector functions10.
In the thymus, these precursor T-cells mature and express either CD4 on helper T-cells or CD8 on cytotoxic T-cells sometimes known as suppressor T cells.
Some T cells (T8 cells) are cytotoxic or killer cells; they act directly on cells bearing antigen (tumor cells and tissue transplanted from an organ donor).