Metabolic and physiologic studies of nonimmune lymphoid cells cytotoxic for fibroblastic cells in vitro

Protective effects of polysaccharides from Cordyceps gunnii mycelia against cyclophosphamide-induced immunosuppression to TLR4/TRAF6/NF-κB signalling in BALB/c mice

Polysaccharides are closely associated with immune regulation. In this study, the aim was to investigate the effect of polysaccharides from Cordyceps gunnii mycelia (PPS) in cyclophosphamide (CTX)-induced immunodeficient mice. Compared with the CTX-induced immunosuppressed mice, the spleen and thymus indexes in mice with orally administered PPS were significantly increased, body weight loss was alleviated, and the natural killer (NK) cytotoxicity and proliferative activities of the lymphocytes were elevated. The recovery of peripheral white blood cells, red blood cells, hemoglobins and platelets was accelerated. Furthermore, the results from ELISA showed that PPS could up-regulate the serum levels of IL-2, IL-12, IFN-γ and IgG, and reduce the level of TGF-β. Histopathological analysis of the spleen revealed the protective effect of PPS against CTX-induced immunosuppression. Western blotting results showed that PPS possessed immunomodulatory activity via TLR4/TRAF6/NF-κB signalling pathways. Finally, the intestinal absorption of PPS was poor, as detected in the Caco-2 transwell system. Taken together, these findings suggest that PPS plays a crucial role in protection against immunosuppression in cyclophosphamide-treated mice and could be a potential candidate for use in immune therapy regimens.

Immunomodulatory Effect of Tremella Polysaccharides against Cyclophosphamide-Induced Immunosuppression in Mice

Polysaccharides are closely associated with immune regulation, but there are different polysaccharide effects from different sources. In this study, the aim was to investigate the effect of tremella polysaccharides (TP) in cyclophosphamide-induced immunodeficient mice. We observed the thymus and spleen index, liver and spleen pathological changes, and the levels of IL-2, IL-12, INF-γ, TGF-β and Ig G in serum, and we also noted the mRNA expression of IL-1β, IL-4, IL-12 and TGF-β in liver and spleen. Besides, we also measured the best effects of different doses of TP (Low-TP was 20 mg/kg·BW, Middle-TP was 40 mg/kg·BW, and High-TP was 80 mg/kg·BW) on cyclophosphamide-induced immunosuppressed mice. The results were remarkable, and suggested that TP had a significant effect for enhancing immunity in cyclophosphamide-induced immunosuppression, and the immune enhancement of High-TP had the best results in TP-treated mice. It could significantly increase the thymus and spleen index, alleviate pathological features of immunosuppression such as the arrangement of liver sinusoid and hepatic plates was disordered, massive inflammatory cells infiltrated and fatty degeneration of hepatocytes in liver, and red pulp and white pulp were intermixed, splenic corpuscles demolished and disappeared, splenic sinusoid extended, and lymphocytes of spleen were reduced in spleen. Besides, it could also up-regulate serum levels of IL-2, IL-12, INF-γ and Ig G, reduce the level of TGF-β in serum, markedly promote mRNA expression of IL-1β, IL-4 and IL-12 in liver and spleen, and suppress mRNA expression of TGF-β. Above all, TP showed preventive effect for cyclophosphamide-induced immunosuppressed mice.

Antigen-driven selection of virgin and memory B cells

This review has summarized the evidence indicating that far more B cells are produced in adult bone marrow than are required to maintain B cell numbers in the periphery. It is shown that most if not all these newly-formed B cells have the potential to become mature peripheral B cells. However, to do this they need to receive an appropriate signal in secondary lymphoid organs. Cells failing to receive such a signal die after a brief period. Two separate situations have been identified which result in recruitment of newly-formed virgin B cells into the peripheral B-cell pool: Following activation by antigen. When the peripheral B-cell pool has been depleted. It is proposed that the first of these signals requires T help and is initiated by antigen presented on interdigitating cells in extrafollicular areas of secondary lymphoid organs. This process seems to be confined to periods immediately following administration of antigen and does not continue in established immune responses to thymus-dependent antigens. It seems probable that continued B cell activation, occurring during long term antibody responses, takes place in the follicles of secondary lymphoid organs and is driven by antigen presented on follicular dendritic cells. Indirect evidence is cited which suggests that somatic mutation in rearranged immunoglobulin V-region genes occurs mainly following B-cell activation in follicles and not during primary B lymphopoiesis. It is suggested that this may involve a hypermutation process which is switched on in activated B cells in germinal centers. Evidence is presented suggesting that plasma cells generated from B cells activated early in immune responses have an average life-span of less than 3 d. However, plasma cells generated in established responses appear to have an average life-span in excess of 20 d. Later sections in the review consider how B-cell recruitment in thymus-independent antibody responses differs markedly from recruitment during thymus-dependent responses. The possible role of splenic marginal zone B cells in some thymus-independent antibody responses is discussed and the evidence indicating that SIgM + ve, IgD-ve marginal zone B cells develop as a distinct population from recirculating SIgM + ve, IgD + ve B cells is summarized.