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Lactococcosis is prevalent on grey mullet (Mugil cephalus) in Hong Kong aquaculture resulting in serious economic loss. A compound formulation of Traditional Chinese Medicines (TCM) (modified Huanglian Jiedu decoction (HLJDD)) comprising Rhizoma coptidis, Radix scutellaria, Cortex phellodendri, Fructus gardeniae, Fructus forsythiae and Flos lonicerae japonicae (in a ratio of 3:2:2:3:3:5) were applied as feed supplements to deal with the disease. The Nitroblue tetrazolium activity in blood, bactericidal activity and total immunoglobulin in plasma were significantly enhanced after feeding 1% of this TCM for 28 days. The disease resistances to Lactococcus garvieae in 1% and 2% TCM feeding groups were significantly enhanced. In the in vitro study, the modified HLJDD also activated the plasma bactericidal activities (p < 0.01). Based on this study, 1% modified HLJDD feeding for 28 days may be an optimal dose to prevent L. garvieae infection and could be used in aquaculture industries. [ABSTRACT FROM AUTHOR]

Changes in cellular energy and redox states in the C6 glioma cells exposed to increasing concentrations of either Zn or Se were studied to examine whether different elements cause different patterns of changes in cellular metabolism. Following a 3-h exposure, both Zn and Se +4 caused dose-dependent decreases in cell viability and total adenosine nucleotides (TAN = ATP + ADP + AMP). In addition, Zn caused a dose-dependent increase in cellular ATP/TAN and a decrease in the ADP/TAN and AMP/TAN. These changes resulted in a significant increase in energy charge potential (ECP = [ATP + 0.5ADP]/TAN). Se +4 , on the other hand, caused a dose-dependent decrease in ATP/TAN but an increase in both ADP/TAN and AMP/TAN, resulting in a dose-dependent decrease in ECP. Both Zn and Se +4 caused a dose-dependent decrease in GSH/GSSG and an increase in GSH + GSSG when compared to TAN. In contrast to Zn and Se +4 , the nontoxic Se +6 caused no significant changes in cellular energy states but reduced the GSH/GSSG ratio from 3.14 ± 0.49 to 2.05 ± 0.29, which could be explained by the effect of Se on enzymes responsible for GSH metabolism. As the cellular ATP level has been considered an important element that mediates the mode of cell death, it was suggested that a significant increase in ATP/TAN upon exposure to Zn would indicate that cell death occurred via apoptosis, while Se +4 caused a different pattern of cell death. This was confirmed by the appearance of cells with fragmented nucleus in cells treated with Zn, but not Se +4 and Se +6 . The results demonstrated that different chemicals caused different patterns of metabolic changes. The correlation between metabolic changes and the mode of cell death was discussed. [ABSTRACT FROM AUTHOR]

A panel of T-cell clones reactive to the soluble egg antigen (SEA) of Schistosoma mansoni is described. The proliferative responses of the primary immune lymph node (LN) cells and T-cell clones to different schistosome antigen preparations (cercarial extract (CE), live or dead schistosomula, adult worm extract, and soluble egg antigen) were compared. Primary immune LN cells could not distinguish between these schistosome antigen preparations. However, when a total of 22 T-cell clones was analysed, a complex pattern of both stage-specific and common (or cross-reactive) antigen reactivity was observed. These patterns have been grouped into four types: (i) five clones were reactive to all different schisto-some antigen preparations; (ii) two clones were reactive only to SEA, CE and schistosomula; (iii) three clones were reactive only to SEA and cercariae; (iv) twelve clones were reactive to SEA antigen alone. The T-cell clones were identified as Thy-1-positive cells. All the clones were able to respond to exogenous IL-2 after antigenic stimulation. However, there was a variable degree of IL-2 responsiveness when compared with antigen-specific stimulation. Four T clones were selected for further studies on the genetic control of the proliferative response to schistosome antigens. One of the proliferative T clones was restricted by the JA subregion of the major histocompatibility complex (MHC), and the other three clones are restricted by the 1E (ACEα) subregion. [ABSTRACT FROM AUTHOR]

Most western countries where vaccination against influenza A virus infection is carried out use vaccines composed of whole inactivated influenza virus or subunit preparations of the virus which contain the haemagglutinin and neuraminidase surface antigens of currently occurring strains. It is generally recognized that the immunity induced is short-lived and is relatively ineffective if variant viruses with different serological specificity arise. Although inactivated or subunit virus preparations can stimulate the production of cytotoxic T cells in adults with assumed previous experience of influenza viruses, similar responses have yet to be demonstrated in immunologically naive children.

Effector T cells (Td) which mediate delayed-type hypersensitivity reactions to influenza A virus can be generated in tissue culture using normal mouse spleen cells as the responder population. Addition of helper T cells enhances but is not essential for the production of Td cells. Both Ly 1 positive, I region restricted and Ly 2,3 positive, K,D region restricted effector cells are generated. Treating the responder cell population with anti-Ly I or anti-Ly 2,3 antibodies and complement prevented the generation of both classes of effector T cell, suggesting that the precursor Td cells are Ly 1,2,3 positive. Effector cells which are specific for the homologous virus or cross-reactive within the A strains of influenza virus are produced, as has been found previously in in vivo experiments. Depleting the cell population of phagocytic and plastic adherent cells resulted in a failure to produce Td cells, which showed a requirement for macrophage-like cells as accessory cells in the primary in vitro generation of Td cells. A variety of cells, such as peritoneal exudate cells, mitogen stimulated blasts or L929 fibroblast cells could serve as stimulator cells. Only Ly 2,3 positive, K,D region-restricted Td cells were produced when L929 cells were used as they lack I region-coded surface antigens. The 1 region-restricted DTH response was mapped to the IA sub-region of the H-2 gene complex. [ABSTRACT FROM AUTHOR]

Injection of infectious hut not of non-infectious influenza A. virus or of infectious or non- infectious Sendai virus intraperitoneally into mice induces the generation of plastic-adherent cell that are able to effect release of 51Cr from labelled virus-infected target cells but not from labelled, uninfected cells. Their activity is greatly diminished by exposure to silica or carrageenan but not by anti-Th 1 antibody and complement treatment. Similarly, the activity of the cell preparation cannot be explained by contamination with natural killer or 'K' cells. Thus, the effector cells were identified as macrophages and for convenience are called 'cytotoxic macrophages'. The maximum cytotoxic activity was recovered from the peritoneal cavity 5 days after virus injection and declined thereafter. Although the effector cells are cross-reactive in that cells activated by an influenza A strain virus lyse target cells infected with the same or other A strain viruses or with Sendai virus, there is preferential lysis of cell infected with the homologous virus, The action of the effector cells is not H-2-restricted. Preliminary experiments showed that similar effector cells can be recovered from the lungs of mice 5 days after intranasal inoculation of infectious influenza virus, so they may contribute to the host control of the disease. [ABSTRACT FROM AUTHOR]