Antibody responses to early antigens of varicella-zoster virus (VZV) during varicella and zoster

The antibody responses to membrane and early antigens and thymidine kinase of varicella-zoster virus (VZV) were studied in sera during both varicella and zoster by a test with fluorescent antibody to membrane antigen (FAMA), staining the biochemically transformed cells by the immunofluorescent technique and neutralization of virus-specific thymidine kinase activity, respectively. Similar increases in FAMA antibody titers were demonstrated in sera from patients with varicella and zoster. IgM was detected in both groups, but appeared earlier during varicella than during zoster. Furthermore, the antibody titers to early antigens and virus-specific thymidine kinase were higher in patients with zoster than in those with varicella. These data suggest that different types of antibody responses occur during varicella and zoster.     

Enhancement of ATPase Activity by a Lipid Peroxide of Arachidonic Acid in Rat Brain Microvessels

The effects of 15-hydroperoxyarachidonic acid (15-HPAA) on Na+, K+- and Mg+-ATPase activities in the blood-brain barrier (BBB) were examined using rat brain microvessels (MV). 15-HPAA markedly stimulated these ATPase activities in MV at low concentrations whereas the synaptosomal Na+, K+-ATPase activity was inhibited in a dose-dependent manner. Further neurochemical analysis revealed that this stimulatory effect of 15-HPAA in MV was not due to a simple detergent-like action of the compound on the membranes but rather to stimulation of the phospholipase A2 and lipoxygenase activity within MV. In addition, it was shown that free radical reactions were involved in the mechanism. Since such anti-edema drugs as 1,2-bis(nicotinamido)propane were proved to be potent suppressors of the enhanced ATPase activity, further speculations on the role of this effect for ischemic brain edema are offered.     

Chemical modification by diethylpyrocarbonate of an essential histidine residue in 3-ketovalidoxylamine A C-N lyase

3-Ketovalidoxylamine A C-N lyase of Flavobacterium saccharophilum is a monomeric protein with a molecular weight of 36,000. Amino acid analysis revealed that the enzyme contains 5 histidine residues and no cysteine residue. The enzyme was inactivated by diethylpyrocarbonate (DEP) following pseudo-first order kinetics. Upon treatment of the inactivated enzyme with hydroxylamine, the enzyme activity was completely restored. The difference absorption spectrum of the modified versus native enzyme exhibited a prominent peak around 240 nm, but there was no absorbance change above 270 nm. The pH-dependence of inactivation suggested the involvement of an amino acid residue having a pKa of 6.8. These results indicate that the inactivation is due to the modification of histidine residues. Substrates of the lyase, p-nitrophenyl-3-ketovalidamine, p-nitrophenyl-alpha-D-3-ketoglucoside, and methyl-alpha-D-3-ketoglucoside, protected the enzyme against the inactivation, suggesting that the modification occurred at or near the active site. Although several histidine residues were modified by DEP, a plot of log (reciprocal of the half-time of inactivation) versus log (concentration of DEP) suggested that one histidine residue has an essential role in catalysis.     

SV40 vector with early gene replacement efficient in transducing exogenous DNA into mammalian cells.

An early replacement SV40 vector, SV40-Mu beta, was constructed by replacing part of the early genes of the virus with mouse interferon-beta (IFN-beta) cDNA. Upon transfection of COS-7 cells with this DNA, transducing viral particles were produced, which could infect various cells and cause efficient production of mouse IFN-beta. The viral stock contained no detectable wild-type SV40. The IFN production after the virus infection was very high in monkey kidney cells, but less so in human epithelial cells, and low in mouse, pig, hamster cells and in human lymphocytes. The efficiency of introduction of the DNA to monkey kidney cells was compared with that by the calcium phosphate precipitation method, and the viral vector was found to be more efficient by a factor of several tens to hundreds.     

Effects of ingested phytoecdysteroids on the growth and development of two Lepidopterous larvae

The effects of ingested or injected 20-hydroxyecdysone on silkworm larvae (Bombyx mori) including death without moulting, death following completion of promoted moulting, death during promoted moulting (ecdysis inhibition) and inhibition in growth with and without effects on moulting, are dependent upon the concentration of exogenous hormone, the precise developmental stage of the treated larvae, and the duration of exposure to the exogenous ecdysteroid. Comparisons of 20-hydroxyecdysone with other phytoecdysteroids in the silkworm and pink bollworm, Pectinophora gossypiella, show a similar but more potent effect induced by ponasterone A, while cyasterone causes an ‘antiecdysone’ effect.     

T cell regulation of B cell activation: antigen-specific and antigen-nonspecific suppressor pathways are mediated by distinct T cell subpopulations

The present studies were carried out to characterize the cellular events involved in the induction and function of carrier-specific Ts cells, which selectively regulate the generation of IgG responses by Lyb-5- B cells. It was demonstrated that this regulation is in fact mediated by two distinct suppressor pathways. In one pathway, carrier-primed Lyt-1 + 2 - Ts cells are specifically activated by in vitro reexposure to the priming antigen. After this specific activation, these Lyt-1 + 2 - Ts cells are able to suppress IgG responses in an antigen-nonspecific manner. This suppression requires the participation of unprimed Lyt-1 - 2 + T cells, and is effective in both the early and the late phases of antibody responses. A second suppressor pathway requires the antigen-specific activation of primed Lyt-1 - 2 + Ts cells. Suppression of antibody responses by activated Lyt-1 - 2 + Ts cells is highly carrier specific, in contrast to the nonspecific effector function of Lyt-1 + 2 - Ts cells, appears to act without requirement for additional T cell populations; and is effective only early in the course of the antibody response. Thus, it appears that two Ts cell populations may function through distinct mechanisms to regulate the generation of IgG Lyb-5- B cell responses.