Granular lymphoid cells

Figure 36 Large Granular Lymphoid Cells (Later Natural Killer Cells) Kill Human Cancer Cells without Pre-Immunization. Reference Appendix 2, Explanations to the Figures...

Immunotoxicity. Studies that assess the potential effects of radium on the immune system of orally or dermally exposed humans have not been located. The case report of a chemist exposed to radium primarily via inhalation for 14 years reported leukopenia and the almost total absence of granular leukocytes, leukoblastic groups, and lymphoid tissue in the bone marrow. No studies on animals exposed via inhalation, oral, or dermal routes have been located. A study reporting a reduction in peripheral white blood cells in intraperitoneally injected rats has been located. The reported observations suggest that immunological effects may be a concern for humans exposed to radium. 

Produced by lymphoid tissue. Lymphocytes represent about 20% of the WBCs in adults they have a long life span (sometimes several years). They probably serve as memory cells for the immune system. These mononuclear cells may be small, agranular structures (T and B cells) or large, granular cells (NKCs). Different types of T cells may only be differentiated by their cell-surface markers (CD markers - clusters of differentiation). CD markers are identified using labelling antibodies... 

Natural killer (NK) cell. A subset of lymphocytes found in blood and some lymphoid tissues, derived from the bone marrow and appearing as large granular lymphocytes. NK cells possess the capacity to kill certain tumour cells or virus-infected normal cells. The killing is not induced by specific antigen and is not restricted by MHC molecules. 

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