Patterns of immunoenhancement and suppression induced by Chlamydia trachomatis in vivo and in vitro

We investigated the cycle of immune enhancement and suppression seen in mice infected with Chlamydia trachomatis by using in vivo and in vitro model systems. BALB/c mice injected intravenously with chlamydia reveal a three- to seven-fold increase in numbers of plaque-forming cells producing antibodies against sheep red blood cells (SRBC), when immunized with SRBC 0 to 5 days after chlamydia infection. When mice are injected with SRBC 10 to 15 days after initial chlamydia infection, the specific anti-SRBC plaque-forming cell response is suppressed two- to three-fold. In vitro, low numbers (2 to 5 X 10(6) bacteria/ml) of chlamydia stimulate potent proliferative responses by B lymphocytes while high numbers (25 X 10(6) bacteria/ml) of bacteria generate strong, general T suppressor activity. This model has important implications for regulation of immune responses that arise at different times during chlamydial infections, as well as for the potential effectiveness of chlamydial vaccines.     

Promotion of Stomatal Opening by Indoleacetic Acid and Ethrel in Epidermal Strips of Vicia faba L

Indole-3-acetic acid (IAA), at concentrations of 0.01 to 1.0 millimolar, and ethephon (0.3% v/v Ethrel) promote stomatal opening when applied to epidermal peels of Vicia faba L. in light or dark. The effect of ethylene is seen by 30 minutes and maximal opening (over two times that of untreated controls) occurs after only 60 to 90 minutes in the light. Stomatal opening by IAA and Ethrel in both light and dark is prevented by 0.14 millimolar AgCl. It is suggested that the effect of added IAA, but not that of light, is linked to ethylene production. The possible role of ethylene in stomatal opening during fungal infection is discussed. The stomates of Vicia faba provide a new system to study the effects of ethylene on certain membrane-regulated processes.     

Chlamydia trachomatis (L2 serovar) can be bound, ingested and destroyed by differentiated but not by undifferentiated human promyelocyte cell line HL-60

As a model system for analysing interactions between chlamydiae and myeloid cells and their precursors, we have studied binding, ingestion and destruction of Chlamydia trachomatis (L2 serovar) by the human promyelocytic cell line HL-60. HL-60 cells were induced by phorbol myristate acetate (PMA) and dimethyl sulphoxide (DMSO) to differentiate along either the macrophage or the granulocyte pathway, respectively. Using an immunofluorescence assay and electron microscopy, we have shown that induced (differentiated) HL-60 cells, but not uninduced (undifferentiated) HL-60 or other cell lines treated with PMA or DMSO, exhibit increased binding, ingestion and elimination of C. trachomatis; these activities are associated with specific histochemical and antigenic markers of myeloid differentiation. These results suggest that myeloid cells acquire the ability to interact with and kill chlamydiae during cell development.     

Enzymatic Protein Carboxyl Methylation in Rat Posterior Pituitary: Neurophysins in Rapid-Turnover Pool Determine Methyl Accepting Capacity

In vitro stimulation of intact rat posterior pituitary by either veratridine or K+ depolarization results in the concomitant release of neurophysins and in a decrease (70-80%) in their carboxyl methylation as measured either with L-[methyl-3H]methionine in the intact lobes after stimulation or in their homogenates with [methyl-3H]S-adenosyl-L-methionine and purified protein carboxyl methyltransferase. A similar reduction in neurophysin methylation (60%) was observed when the arrival of newly synthesized neurophysins at the posterior pituitary was blocked by colchicine. Experimental data indicate that the reduction in neurophysin content of the lobes after 12 h of colchicine treatment (less than 7%) or after in vitro stimulation (about 10%) cannot account for the marked reduction in neurophysin methylation. The results suggest that the granule pool characterized by rapid turnover of neurophysins probably represents the major source of methyl acceptor proteins in the lobe. In spite of the marked reduction in neurophysin methyl accepting capacity observed after stimulation, there was no parallel increase in methyl accepting capacity of the released neurophysins. We propose that a neurophysin subfraction that might be associated with the membrane of releasable granules participates in the methylation reaction in situ.     

Cytotoxic and cytolytic activity of nonadecafluoro-n-decanoic acid on Acholeplasma laidlawii.

We studied the interactions between the perfluorinated fatty acid nonadecafluoro-n-decanoic acid (NDFDA) and the cell wall-less procaryote Acholeplasma laidlawii, which were cultured in an identical medium base but with different serum supplements. When grown in mycoplasma media supplemented with PPLO serum fraction (Difco Laboratories, Detroit, Mich.), A. laidlawii was rapidly killed by low concentrations of toxicant (less than 1.0 mM). At higher concentrations (greater than 10 mM), NDFDA treatment appeared to lyse cells. A. laidlawii cells grown in horse serum-supplemented mycoplasma media were both killed and lysed at the same NDFDA concentration (greater than 10 mM). These data suggest that this perfluorinated fatty acid can be cytotoxic and cytolytic to mycoplasmas. Changes in active concentrations occurred in parallel with changes in growth medium serum supplementation, which is known to alter mycoplasma membrane composition. We propose that NDFDA interacts with the membranes of A. laidlawii cells, resulting in cell death or cell lysis or both.     

Liver glutathione S-transferase polymorphism in Japanese and its pharmacogenetic importance

Summary A total of 168 autopsy liver extracts from Japanese individuals were examined for the glutathione S-transferase (GST) isozymes by means of starch gel electrophoresis. The gene frequencies of GST1^*1, GST1^*2, and GST1^*0 in Japanese were 0.252, 0.057, and 0.691, respectively. GST1^*3 was detected as a rare variant allele. The incidence of GST1 0 in 41 liver biopsy samples from patients suffering from various liver diseases was investigated using polyacrylamide gel isoelectric focusing. The GST1 0 phenotype was found more frequently in livers with hepatitis and carcinoma than in control livers. The isozymes coded by different GST loci were partially purified and characterized to study their biochemical properties. The apparent Km values with 1-chloro-2,4-dinitrobenzene (CDNB) as substrate for the isozymes at the GST1, GST2, GST3, and GST4 loci were 604, 1345, 776 and 591 M, respectively.     

Cloning and expression of a functional fucose-specific lectin from an orange peel mushroom, Aleuria aurantia

Aleuria aurantia lectin (AAL) shows sugar-binding specificity for L-fucose. A λgt11 expression library was constructed from A. aurantia poly(A) RNA and screened with a polyclonal antiserum directed against AAL. An immunopositive clone carrying 1.3-kb EcoRI fragment was obtained. The fragment encoded AAL, but lacked a nucleotide sequence corresponding to the two amino-terminal amino acids. The 5′-terminal part of the fragment was replaced with a chemically synthesized DNA fragment and inserted into an expression vector to yield a plasmid pKA-1. Escherichia coli carrying pKA-1 expressed functional AAL and the recombinant AAL showed the same immunological properties as those of natural AAL.