Masayasu Nakano

In Vitro Adjuvant Effect of Endotoxin

Mishell and Dutton (1967) devised a method that initiates an immune response in cultures of free spleen cells from unimmunized mice. This method allows the investigation of biochemical and cellular events associated with induction and development of the immune response and enables the investigator to use an intrinsically simpler system for analysis than is true when intact animals are employed.

Mitogenic activity of bacterial lipopolysaccharide on the .GAMMA..DELTA. T lymphocyte.

In vitro proliferative responses of T lymphocytes to bacterial lipopolysaccharides (LPS) were examined by determining the uptake of tritiated thymidine (3H-TdR) into cells. T lymphocyte populations were taken and purified from proteose peptoneinduced peritoneal exudate cell (PEG), spleen and thymus of C3H/HeN or C3H/HeJ mice. LPS were prepared from Salmonella typhimurium, Porphyromonas gingivalis, Prevotella intermedia and Fusobacterium nucleatum by the phenolwater proceduce.The T lymphocytes taken from PEG (PEG-T) of C3H/HeN mice showed an increased 3H-TdR uptaken in response to LPS from S. typhimurium (S. t-LPS), while PEG-T of G3H/HeJ, splenic T and thymic T lymphocyte of C3H/HeN mice did not respond to S. t-LPS. Other LPS also have a mitogenic ability to PEG -T lymphocytes too, while those of S. t-LPS and P. i-LPS were higher than that of F. n-LPS or P. g-LPS. The response of PEG from C3H/HeN mice to S. t-LPS was abolished, when the PEG-T were pretreated with anti-Thy-1 orγδTCR antibody plus complement (c), but not anti-αβTCR antibody plus C. The thymic T lymphocytes did not show any increase of 3H-TdR uptake in response to LPS or anti-γδ TCR antibody. However, obvious uptake did occur when the cells were stimulated with LPS and anti-γδ TCR antibody together.The results suggest that LPS has a mitogenic ability to a T lymphocytes population bearing γδ TCR in PEG that had been stimulated previously by proteose peptone.

Synergistic Effect of Endotoxin with Concanavalin a on DNA Synthesis in Lymphocytes and the Role of Interleukins 1 and 2

Bacterial lipopolysaccharide (LPS) extracted from the cell walls of gram-negative bacteria has a number of effects on the cells of the immune system (see 21 for review). The effects of LPS on macrophages (Mo) and B lymphocytes are very prominent. Mo activated by LPS increase their phagocytic ability (20,21), pinocytosis (5,30), oxidative metabolism (15,25), synthesis of cellular proteins including lysosomal enzymes (19,20), secretion of collagenase (36) and arginase (4), tumor cytotoxicity (33), microbicidal activity (27), interleukin (IL) 1 (18), colony-stimulating factor, and interferon (21). When murine splenic B lymphocytes are stimulated by LPS, about one-third of the B lymphocytes initiates DNA synthesis (13), and subsequently, these activated B lymphocytes produce antibodies polyclonally (21). However, its effect on human peripheral B lymphocytes is not obvious (21,26,29), unless these cells are cultured for long periods of time (seven to nine days) with prescreened lots of fresh human serum (17). On the contrary, LPS has no obvious mitogenic effect on T lymphocytes, except on a very small percentage of cells (35), and it is incapable of initiating T lymphocytes to produce lymphokines. However, if T lymphocytes are activated by T cell stimulants, the T lymphocytes seem to be able to accept the stimulus of LPS. The combination of some kinds of phytomitogens with LPS can synergistically enhance the blastogenic responses of thymocytes in mice (7,24,32), spleen lymhocytes of rats (8) or peripheral blood T lymphocytes of humans (12,29) as measured by increase[3H]thymidine ([3H]TdR)uptakes.