Jay H. Menna

Methyl gallate, methyl-3,4,5-trihydroxybenzoate, is a potent and highly specific inhibitor of herpes simplex virusin vitro. II. Antiviral activity of methyl gallate and its derivatives

Methyl gallate (MG), methyl-3,4,5-trihydroxybenzoate, was highly active against herpes viruses as determined by plaque reduction assay. Herper simplex virus type 2, MS strain, was sensitive to MG at a mean 50% inhibitory concentration (IC50) of 0.224 μg/ml in monkey kidney cells. MG was specific for herpes viruses with the relative sensitivity HSV-2>HSV-1>CMV. Two RNA viruses tested were significantly less sensitive to MG. The structural components of MG which modulate the anti-herpetic activity were identified by analysis of chemical analogues. Our structural analyses indicated that three hydroxyl groups were required but were not sufficient for the anti-herpetic action of MG. The presence and chain length of the alkyl ester were also important to the anti-herpetic activity of MG. Methyl gallate may interact with virus proteins and alter the adsorption and penetration of the virion.

The effect of prenatal chlordane exposure on the delayed hypersensitivity response of BALB/c mice

Previous studies in our laboratory have indicated that in utero chlordane exposure caused a significant enhancement in the survival of the offspring to influenza virus infection. Further studies, reported here, show that the non-specific delayed type hypersensitivity (DTH) response to oxazolone at 100 days of age, but not at 30 days of age, was significantly depressed. In contrast, the Con A-induced blastogenic response of spleen cells from chlordane-treated offspring was not depressed and was, in fact, significantly enhanced. However, neither the response to PHA nor to LPS mitogens was significantly altered. In utero exposure to chlordane significantly depressed the mixed lymphocyte reactivity (MLR) of spleen cells from male offspring, whereas females showed no significant alteration of MLR. The significant depression of the DTH and MLR responses supports our previous reports of enhanced survival of influenza virus infection following in utero exposure to chlordane, since active DTH contributes to the pathology of influenza virus infection in mice. The normal or enhanced T-cell mitogen response suggested that the chlordane-induced depression of DTH and MLR was not due to overt toxicity to T-cells.

Methyl gallate, methyl-3,4,5-trihydroxy-benzoate, is a potent and highly specific inhibitor of herpes simplex virusin vitro. I. Purification and characterization of methyl gallate fromSapium sebiferum

A potent anti-herpetic compound was identified and purified to homogeneity from the leaves ofSapium sebiferum by plaque reduction assay using herpes simplex virus type 2. The chemical structure of the purified compound was determined by mass spectroscopy and proton and carbon-13 nuclear magnetic resonance as methyl gallate, methyl-3,4,5-trihydroxybenzoate. This is the first demonstration that methyl gallate is a potent anti-herpetic compoundin vitro, present in high concentration in the leaves ofS. sebiferum, a Chinese folk medicine for shingles.

Influenza type a virus infection of mice exposed in utero to chlordane; survival and antibody studies

Previous studies carried out by others have shown that in utero exposure of mice to chlordane effects a significant depression of cell-mediated immunity (CMI) at 100 days of life without adversely affecting the humoral immune system. In the studies reported herein we assessed the effect of in utero exposure to various doses of chlordane on the response of 38-day-old mice to influenza type A virus infection in terms of relative levels of mortality, mean day of death, and the levels of antiviral antibody in the primary and secondary immune response to the virus. In utero exposure to chlordane effected enhanced survival to influenza type A virus infection relative to mock-treated animals. No significant differences were noted in the mean day of death of chlordane-treated and mock-treated mice. A significant enhancement in the levels of antiviral antibody was noted in the chlordane-treated female mice but not male mice in both the primary and secondary immune response to the virus.

Cytotoxic T-lymphocyte and NK responses in mice treated prenatally with chlordane.

It has been reported previously that BALB/c mice, treated in utero with chlordane, showed increased survival to influenza A/PR/8/34 [H1N1] (influenza) virus as young adults. To determine the possible role of cell-mediated immunity (CMI) on this effect, cytotoxic T-lymphocyte (CTL) and natural killer (NK) cell activities were assessed on chlordane-exposed offspring at 100 and 200 days post partum. The CTL response of these offspring showed no significant change from that obtained from their sex- and age-matched control counterparts exposed prenatally to the vehicle. NK responses of chlordane-exposed female offspring were significantly higher at 100 days of age but not at 200 days of age. Although male offspring that were exposed to chlordane prenatally showed no difference in NK cell activity at 100 days of age, NK cell activity was significantly less in chlordane-treated animals than controls at 200 days of age. Thus, prenatal treatment of mice with chlordane had varying effects on the NK cell activity of adult offspring, depending on the sex and age of the animal. It is concluded that the previously reported increase in survival to influenza is due to a resolution of the infection by normal CTL and NK cell activities coupled with a decrease in delayed-type hypersensitivity (DTH)-mediated pathology.

The effect of prenatal chlordane exposure on specific anti-influenza cell-mediated immunity

Previous studies in our laboratory have documented that in utero chlordane exposure caused a significant enhancement in the survival of the offspring to influenza A virus infection, and a depressed delayed type hypersensitivity (DTH) response to oxazolone. To correlate these 2 effects, we assayed influenza A virus-specific DTH response, and found that it was significantly decreased in chlordane-treated offspring. Virus-specific T-cell blastogenesis was also assayed in chlordane-treated animals. No significant differences due to the chlordane treatment were found in virus-specific T-cell blastogenesis, suggesting that the DTH depression did not result from a paucity of antigen-reactive T-cells. To determine whether enhanced survival was due, in part, to the effects of chlordane on virus replication, rather than on immunological alteration alone, the kinetics of influenza virus replication in the lungs of chlordane- and vehicle-treated animals were determined. In utero chlordane treatment caused no significant differences in in vivo virus replication. These data suggest that increased survival was due to a decrease in virus-specific DTH and its associated pathology.

Regular articleLong-term alteration of adult bone marrow colony formation by prenatal chlordane exposure

Female mice were treated with either 0, 4, or 8 mg of chlordane per kilogram body weight daily for 18 days during pregnancy. The offspring of these mice were assayed for bone marrow hematopoietic activity at 100 and 200 days of age. Hematopoietic activity was evaluated for in vitro granulocyte-macrophage colony-forming units (GM-CFU) and in vivo spleen CFU (CFU-S). The consistent finding was a significant depression both of the numbers of bone marrow GM-CFU and of the CFU-S in offspring exposed to either 4 or 8 mg/kg chlordane even at 100 and 200 days after cessation of treatment. Prenatal treatment with chlordane did not affect the number of recoverable viable bone marrow cells at either of these time points. Ontological development was selectively affected by chlordane exposure, since subchronic (18 day) treatment of adult mice did not significantly alter bone marrow GM-CFU or CFU-S levels. These data suggest that the decreased delayed-type hypersensitivity reactions noted previously in mice exposed to chlordane prenatally may be due to a change in the functional capacity of myeloid lineage cells rather than altered T cell function.

Alteration of fetal liver colony formation by prenatal chlordane exposure

Female mice were treated with 0 or 8 mg/kg chlordane daily for 18 days during pregnancy. The fetuses of these mice were assayed for fetal liver hematopoietic activity at 18 days gestational age. Hematopoietic activity was evaluated for in vitro granulocyte-macrophage colony-forming units (GM-CFU) and in vivo spleen CFU (CFU-S). The consistent finding was a significant depression of the numbers of both fetal liver GM-CFU and CFU-S without a change in liver cellularity in fetuses exposed to 8 mg/kg chlordane. These data show that the damage to stem cells that persists into adult life as a result of chlordane exposure, as reported earlier by Barnett et al. (1990) Fundam. Appl. Toxicol. 14, 688-695, occurred during the fetal period.

Influenza type a virus infection of suckling mice pre-exposed to insecticide carrier

Suckling CD-1 outbred mice exposed topically to insecticide carrier (IC), a mixture of emulsifiers and solvent, were rendered less sensitive to infection with lethal doses of influenza type A/PR8/34 (H0N1) virus than untreated and mock-treated control mice. Decreased sensitivity to influenza type A/PR8/34 virus infection was evidenced by a significant increase in the mean percent survival of the mice. In addition, a 10- to 100-fold reduction in the 50% lethal titer of the stock virus was observed in IC-treated mice relative to untreated mice. Decreased sensitivity was virus dose related and occurred within a dose range of 2 to 8 X LD50. No decrease in mortality rate was observed as a function of exposure to IC.

Effect of emulsifiers on influenza type a virus infection, in vivo and in vitro studies

Results of in vitro studies carried out by other investigators suggest that insecticide emulsifiers enhance the replication of animal viruses possessing a single-stranded RNA genome. Based on this observation and on epidemiological findings, it has been postulated that insecticide emulsifiers and related compounds may be etiologically involved in Reyes syndrome. Reyes syndrome is an enigmatic pernicious disease of childhood causally associated with an antecedent viral infection, usually influenza, and putatively associated with exposure to environmental chemicals. The present study was carried out to assess the effects of emulsifiers on infection in vivo with influenza type A virus, a virus possessing a single-stranded RNA genome, using the suckling mouse as host, and in vitro using a susceptible line of mammalian cells. Three coded emulsifiers retrospectively identified as Atlox 3409F, Toximul MP8, and Triton X-100 were assayed at concentrations of 1.0, 2.5, 5.0, and 10.0 ppm. None of the emulsifiers enhanced the plaquing efficiency of influenza A/PR/8/34 (HON1) virus in Madin-Darby canine kidney cells (less than a twofold increase), nor did percutaneous application of these emulsifiers at a concentration of 21 parts per thousand in peanut oil enhance the lethality of influenza A/PR/8/34 (HON1) virus infection. Indeed, peanut oil alone, and in combination with the emulsifiers, lowered lethality relative to mice that were treated percutaneously in parallel with physiologic saline.