Humoral antibody response in animals infected with virulent rinderpest virus

Humoral antibody responses in cattle or rabbits infected with virulent rinderpest virus or lapinised rinderpest virus respectively were assessed. Rinderpest specific antibodies could be first detected 6 days post-infection. No correlation could be established between antibody response and the course of the disease in infected animals during the early stages of infection. The animals with fatal infection either did not respond or had a transient antibody response. A gradual increase in antibody titre from 7 days post-infection was observed in animals which ultimately recovered.

Effect of ammonium chloride on multiplication of rinderpest virus in Vero cells

Ammonium chloride, a lysosomotropic weak base, inhibited replication of rinderpest virus in Vero cells. The inhibition of replication was dose-dependent and the minimum effective dose of ammonium chloride was determined as 5-10 mmol/l. The fusion efficiency and the yield of both cell-free and cell-associated virus were reduced in the presence of the inhibitor. Western blot analysis of rinderpest virus-infected Vero cells revealed that synthesis of two virus-induced polypeptides were affected by the presence of ammonium chloride.

Interferon-inducible gene expression in HL-60 cells: effects of the state of differentiation

The promyelocytic leukemia line HL-60 can be terminally differentiated in vitro to either monocyte/macrophages or granulocytes. We used this cell line to test whether the state of differentiation of a cell changes its response to interferon (IFN). The characteristics of expression of several IFN-alpha- and IFN-gamma-inducible genes in undifferentiated and differentiated HL-60 cells were examined. p67, an IFN-gamma-inducible protein, was induced similarly in three cell types, whereas another IFN-gamma-inducible protein, p56, was induced strongly only in undifferentiated cells. In contrast, two isozymes of 2,5(A)-synthetase were induced better in differentiated cells in response to either IFN. Several IFN-alpha-inducible mRNAs, e.g., 561, 6-16, 1-8, and 2A, were induced much more strongly in granulocytes than in macrophages or in undifferentiated cells. Electrophoretic mobility shift assays using the IFN-stimulated response element of gene 561 and nuclear extracts of IFN-alpha-treated cells revealed the appearance of one complex and the disappearance of another one, concomitant with differentiation of the cells to granulocytes. These observations suggest that expression of IFN-inducible genes in HL-60 cells is regulated by trans-acting factors whose activity changes with the state of differentiation of the cells. Our study may have implications in the optimal clinical use of IFNs. Inducing cellular differentiation may augment the efficacy of IFNs as antitumor agents.

Role of protein phosphorylation in activation of interferon-stimulated gene factors

Possible involvement of protein phosphorylation in interferon (IFN)-mediated activation of IFN-stimulated gene factor 3 (ISGF3) was investigated. For this purpose, in vivo experiments with specific inhibitors of protein kinases and in vitro experiments with protein phosphatases were carried out. In HeLaM cells, 2-aminopurine, an inhibitor of double-stranded RNA-dependent protein kinase, blocked the induction of ISGF3 gamma subunit but not the activation of ISGF3 alpha subunit. A series of experiments using combinations of protein and RNA synthesis inhibitors and 2-aminopurine indicated that the block elicited by 2-aminopurine was at the level of ISGF3 gamma mRNA synthesis. Activation of ISGF3 alpha, although insensitive to 2-aminopurine, was completely blocked by 10 nM staurosporine, an inhibitor of protein kinase C. On the other hand, even 500 nM staurosporine did not block the induction of ISGF3 gamma. Incubation of cytoplasmic or nuclear extracts of IFN-treated HeLaM cells in vitro with alkaline phosphatase completely eliminated their ability to form the ISGF3 complex but not the ISGF1 complex. Treatment with acid phosphatase, on the other hand, changed the electrophoretic mobility of the ISGF3 complex but did not obliterate it. Complementation experiments revealed that ISGF3 alpha was the alkaline phosphatase-sensitive component of the complex. These results suggest that a protein kinase C-mediated phosphorylation step is involved in ISGF3 alpha activation and a 2-aminopurine-sensitive component is involved in ISGF3 gamma mRNA induction.

Inhibition of interferon-inducible gene expression by adenovirus E1A proteins: block in transcriptional complex formation

Infection with wild-type adenovirus 5, but not with a mutant lacking the E1A gene, prevented the induction by interferon (IFN) alpha of chloramphenicol acetyltransferase (CAT) activity in HeLaM cell lines that had been permanently transfected with chimeric CAT reporter genes driven by the transcriptional regulatory regions of the IFN-responsive genes 561 and 6-16. Similar inhibition of IFN-inducible CAT activity was observed in cells that were cotransfected with the same reporter genes and plasmids expressing either the E1A 289- or 243-amino acid protein. These proteins also prevented the induction of CAT activity by IFN-gamma from a cotransfected HLA-DR alpha-CAT gene. Experiments with E1A mutants mapped the inhibitory activity to amino acid residues 38-65 of these proteins. In a HeLa cell line permanently expressing the E1A 289-amino acid protein, the replication of vesicular stomatitis virus and encephalomyocarditis virus was not inhibited by IFN-alpha, suggesting a global blockade of IFN responses. In accord with this theory, induction of 561, 1-8, and (2'-5')oligoadenylate synthetase mRNAs by IFN was blocked in these cells at the transcriptional level. The observed transcriptional inhibition could be attributed to the lack of formation of the crucial IFN-stimulated gene factor 3 (ISGF3) transcriptional complex. As shown by mobility shift assays, this complex was not formed in the nuclear extracts of IFN-treated adenovirus-infected cells or IFN-treated E1A-producing cells. These nuclear extracts were deficient in both ISGF3 alpha and ISGF3 gamma subunits. However, they did not block the formation of ISGF3 complex from exogenously added components.

Cloning, sequencing, and expression of two murine 2'-5'-oligoadenylate synthetases. Structure-function relationships

2'-5'-oligoadenylate synthetases constitute a multimember family of interferon-inducible enzymes which need double-stranded RNA as an obligatory cofactor. We have isolated cDNA clones for two new murine synthetases. These two clones, 9-2 and 3-9, encoded proteins of 414 and 363 amino acid residues, respectively, out of which the amino terminal 346 residues were almost identical. They were also very similar to the corresponding regions of human synthetases E16 and E18. On the other hand, the carboxyl-terminal 68 residues of clone 9-2 had no homology with the carboxyl-terminal residues of E18. These murine clones had only 67% amino acid identity with the previously isolated murine synthetase clone L3. 9-2 and 3-9 proteins were expressed efficiently by in vitro transcription and translation of cDNA clones containing the synthetase coding regions preceded by the 5'-untranslated region of the vesicular stomatitis virus NS gene. These in vitro synthetized proteins bound to double-stranded RNA and catalyzed the synthesis of 2'-5' oligoadenylates. A nested set of deletion mutants of the 9-2 clone was produced by restriction digestion and polymerase chain reaction. Functional testing of the corresponding truncated proteins revealed that a region between amino acid residues 104 and 158 was necessary for binding to double-stranded RNA and a region between residues 320 and 344 was necessary for enzyme activity. Moreover substitution of the lysine residue at position 333 by arginine did not affect the enzyme activity.

Enhancement of expression of exogenous genes by 2-aminopurine. Regulation at the post-transcriptional level

In human and mouse cell lines, expression of exogenous genes was enhanced by treatment with 2-aminopurine (2-AP). Chloramphenicol acetyltransferase (CAT) and neomycin phosphotransferase activities were increased by up to 50-fold upon 2-AP treatment of cells permanently transfected with genes encoding these enzymes. Neomycin phosphotransferase activity was also increased by this treatment in cells infected with a retroviral vector carrying the neomycin phosphotransferase gene. 2-AP-mediated increase in CAT activity was observed in various cell lines which had been permanently transfected with chimeric CAT genes containing transcriptional regulatory elements of the interferon-inducible genes 6-16 and 561, SV40 early genes, mouse mammary tumor viral gene, or metallothionein II gene. The increase in the cellular CAT enzymatic activity was due to an elevated level of CAT protein. The 2-AP-mediated enhancement of CAT expression was operative at the translational level; the rate of transcription of CAT mRNA or its steady-state level was affected only marginally. The translational up-regulation by 2-AP was restricted to the genes introduced from outside; there was no gross change in the rate of synthesis of other cellular proteins.

Gene induction by interferons: functional complementation between trans-acting factors induced by alpha interferon and gamma interferon

HeLaM is a variant cell line in which the transcriptional induction of many genes by alpha interferon has special characteristics (Tiwari et al., Mol. Cell. Biol. 8:4289-4294, 1988). The same characteristics were also displayed for induced transcription of a permanently transfected chimeric gene containing the interferon-stimulated response element of gene 561. For understanding the molecular basis of the special requirements of HeLaM cells, an analysis of the interferon-stimulated gene factors (ISGF) was undertaken. By using gel shift assays, it was shown that the activation of ISGF3 by alpha interferon treatment of HeLaM cells had characteristics identical to those of induced transcription: inhibition by 2-aminopurine and the need for ongoing protein synthesis which was obviated by pretreating the cells with gamma interferon. Upon mixing in vitro the cytoplasmic fraction of gamma interferon-treated HeLaM cells with that of cells treated with alpha interferon and cycloheximide, active ISGF3 was reconstituted, presumably through complementation of two components, ISGF3 gamma and ISGF3 alpha, present in the two respective fractions. Because, unlike other cells, untreated HeLaM cells did not contain detectable levels of either component, we could induce them individually and study their independent properties. Induction of ISGF3 gamma but not of ISGF3 alpha needed ongoing protein synthesis and was blocked by 2-aminopurine. Once induced, ISGF3 gamma was active for 24 h and was present in both the nuclear and cytoplasmic fractions. Activated ISGF3 alpha, on the other hand, did not translocate to the nucleus in the absence of ISGF3 gamma, and in the cytoplasm its activity decayed within 2 h of its activation. In reference to our working model, all of the above observations indicate that ISGF3 gamma is the product of signal 1 and ISGF3 alpha is the product of signal 2.

Biochemical evidence for mediatory role of 5-hydroxytryptamine in the uterotonic action of prostaglandin F2oc

5-Hydroxytryptamine (5-HT) is reported to be involved in endogenous prostaglandin (PG)--modulated as well as exogenous PG-induced pharmacological activities including oxytocic effect of PGE1 PGE2oc Biochemical parameters were undertaken for further studies into the possible role of 5-HT in the uterotonic effect of PGF2oc on isolated oestronised rat uterus. The results substantiate the involvement of endogenous 5-HT in the uterotonic effect of PGF2oc.

Identification of the gene homologous to HSV major DNA binding protein in the BHV-1 genome

By means of Southern blot hybridisation using a cloned herpes simplex virus (HSV) major DNA binding protein (MDBP) gene as probe, the putative MDBP gene of BHV-1 was located within the Hind III G fragment which mapped between 0.352 and 0.381 map units of the BHV-1 genome. Moreover, an antiserum raised to HSV MDBP precipitated a 120kD polypeptide in a radio-immunoprecipitation test.

Epidermal growth factor and phorbol ester regulate prolactin gene expression via distinct pathways

Previous studies, involving phosphorylation of cytoplasmic proteins and localization of DNA regulatory elements, have suggested that epidermal growth factor (EGF) and 12-O-tetradecanoylphorbol-13-acetate (TPA) have similar actions on prolactin (PRL) gene expression by pituitary (GH) cells. However, little is presently known about whether the actions of these two factors involve common gene-distal intermediates. In the present study, we have employed two approaches to examine this question. Chronic exposure of GH3 cells to TPA, which strongly down-regulates protein kinase C activity, completely inhibited acute TPA stimulation of transient expression of a transfected PRL promoter construct ((-187)PRL-CAT), but did not inhibit EGF stimulation of either accumulation of endogenous PRL mRNA or of expression of (-187)PRL-CAT. Furthermore, the acute stimulatory effects of EGF and TPA on expression of (-187)PRL-CAT were additive. Each of these observations implies that EGF and TPA have gene-distal actions on PRL gene expression that are at least partially non-overlapping.

Calcium induction of the mRNAs for prolactin and c-fos is independent of protein kinase C activity

Ca2+ is a strong regulator of the expression of a limited number of eukaryotic genes, including prolactin and c-fos. However, little is known about the cellular signal transduction pathways involved in the action of this ion on specific gene expression. The Ca2+-dependent enzyme protein kinase C has been implicated in other transcriptional pathways regulating the prolactin and c-fos genes. We therefore employed down-regulation of protein kinase C in rat pituitary cells to investigate whether this enzyme is involved in Ca2+ regulation of expression of either of these genes. Exposure of Ca2+-deprived GH3 cells to this ion in the presence of the Ca2+ channel modulator Bay K8644 yielded large increases in the mRNAs for both prolactin and c-fos. Incubation of cells with the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) yielded a 7- to 15-fold decrease in the enzymatic activity of C kinase assayed in vitro, but little or no effect on Ca2+ stimulation of cellular levels of either mRNA. The latter observation was apparently not due simply to an inability of TPA to down-regulate the gene-regulatory activity of kinase C in intact GH3 cells, since this phorbol ester blocked the stimulation by platelet-derived growth factor of cellular levels of c-fos mRNA. TPA treatment also yielded no significant effect on the kinetics of the Ca2+-stimulated accumulation of either mRNA, implying that kinase C is not required at any stage of the Ca2+ induction of these two genes.

Purification and properties of an angiotensin-binding protein from rabbit liver particles

An angiotensin II-binding protein was purified more than 8000-fold after solubilization from rabbit liver particles with digitonin. The procedure comprised fractionation with ammonium sulfate, chromatography on DEAE-cellulose and Affi-Gel 501, gel filtration through Sephacryl S-200, and chromatography with hydroxylapatite. The purified preparation exhibited Kd and Bmax values of 6.7 nM and 8.4 nmol of angiotensin II bound/mg protein. The latter figure represents more than 60% of the theoretical value calculated for a protein of Mr 75,000 as estimated for the major protein component by gel electrophoresis. The purified preparation displayed comparable or slightly higher affinities for various angiotensin antagonists and angiotensin III than that for angiotensin II, whereas angiotensin I as well as the hexapeptide and smaller carboxy-terminal fragments were less tightly bound. Binding of angiotensin II by the isolated protein was highly dependent upon the presence of p-chloromercuriphenylsulfonic acid and also required ethylene diaminetetraacetic acid which could be almost completely replaced by ethylene glycol bis(beta-aminoethyl ether) N,N'-tetraacetic acid but not by o-phenanthroline.

Detection of goat pox antigen and antibody by the counter immunoelectrophoresis test

The counterimmunoelectrophoresis (CIE) test was standardised for the detection of goat pox antigen and antibody using inactivated antigens. The chloroform inactivated and live antigens were equally sensitive for detection of goat pox precipitins. The precipitinogens of goat pox virus (GPV) were found to be soluble in nature. The CIE test was quick as well as more sensitive than the agar gel precipitation test for detection of GPV antibody/antigen. The CIE employing inactivated antigen has been used for the first time in the detection of GPV antibodies/antigens.

Single radial hemolysis test for the detection of rinderpest antibody

The single radial hemolysis [SRH] test was employed for detection of rinderpest antibodies in post-vaccinated serum samples as also in serum samples from animals recovered from rinderpest infection. The results were compared with counterimmunoelectrophoresis [CIE] and serum neutralisation [SN] tests. The CIE test was found to be more sensitive than SRH but because of ease and simplicity SRH can also be used for monitoring antibody development after vaccination.

Introduction of bacterial components in postadsorbed plasma during adsorption with Staphylococcus aureus

In vitro plasma adsorption over either protein A-positive Staphylococcus aureus Cowan I (SAC) or protein A-negative S. aureus Wood 46 (SAW) led to leaching of bacterial biomolecules in the postadsorbed plasma. Presence of bacterial moieties was demonstrated in the postadsorbed plasma by more than one method: (1) using radiolabeled bacteria for adsorption with plasma and detecting radioactivity in the postadsorbed plasma, (2) gel filtration of pre- and post-adsorbed plasmas over Sephadex G-200 column and detecting additional peak(s) in the postadsorbed plasma, and (3) immunoelectrophoretic analysis of pre- and postadsorbed plasmas and their column fractions against rabbit anti-SAC antisera and demonstrating new precipitin bands in postadsorbed plasma. Using an extracorporeal plasma adsorption procedure in mongrel dogs, with radiolabeled SAC as the adsorbent, we have demonstrated the presence of radioactivity in both the adsorbed and filtered (0.2 micron) blood entering into the body, and the adsorbed blood that passed out of the body to reenter into the extracorporeal circuit. These data suggest that components of S. aureus origin enter into the host circulation during both in vitro and ex vivo plasma adsorption, although the exact nature of those extracted staphylococcal components remains unknown. This observation is of much significance since it can possibly help elucidate the mechanism of tumor regression observed following perfusion of plasma over SAC or SAW, followed by its reinfusion to the host.

Rescue of rats from large dose cyclophosphamide toxicity using protein A

Cyclophosphamide (Cy) is widely used as an effective cytotoxic drug, but its use is limited because of its toxicity. In this report, we describe for the first time the ability of purified protein A (P) of Staphylococcus aureus to reduce Cy-induced toxicity in rats. Protein A-treated animals recover quickly from the toxic effects of Cy. The antitumor property of Cy is not reduced in the P + Cy group. In fact, the latter showed a persistent decrease in tumor volume compared with the Cy group. Protein A may prove to be an effective agent in increasing the therapeutic index of Cy.

Antibody response of cattle to rinderpest vaccine

Antibody production was studied in cattle infected with rinderpest vaccine virus. Vaccinated cattle produced both IgM and IgG serum antibodies. The IgG antibodies were mainly those of IgG2 subclass. No IgA antibody response was detected in vaccinated animals.

Detection of rinderpest antibodies

Rinderpest antibodies were detected by employing the fluorescent antibody test (FAT) and the immunoperoxidase test (IPT) and the results were compared with the counterimmuno electrophoresis test (CIE). FAT was found to be the most sensitive in detecting post-vaccinal antibodies followed by IPT and CIE tests.

Inhibition of rat mammary tumor growth by purified protein A--a potential anti-tumor agent

Intravenous inoculations of purified Protein A of Staphylococcus aureus Cowan I cause significant (p less than 0.01) regression of di-methyl-benz-anthracene (DMBA)-induced mammary adenocarcinomas in Sprague-Dawley rats. Direct tumor cell counts of treated tumors showed fewer (p less than 0.005) viable tumor cells than did tumors from untreated controls. Plasma immunoglobulin G concentration showed a significant (p less than 0.05) increase compared to that of controls. However, the concentration of immune complexes and percentages of T-rosettes did not change. Peripheral blood mononuclear cells (PBMNC) from treated animals showed increased cytotoxicity (p less than 0.005) compared to that of controls. Plasma of treated animals potentiated PBMNC cytotoxicity (p less than 0.05) and showed increased antibody and complement-mediated cytotoxicity (p less than 0.025). The exact mechanism of protein A-induced potentiation of anti-tumor immune reactivities leading to tumoricidal response is not known. However, our data are suggestive of the involvement of both cellular and humoral immunity of the host in the tumor regressive phenomenon.

Effects of L-ascorbic acid supplementation on dieldrin toxicity in rats

Chronic dieldrin administration to rats (5 mg/kg/day) produced pathological changes in liver and kidney tissues. Dieldrin treated rats showed high levels of liver ascorbic acid and increased activities of inorganic pyrophosphatase in brain and glucose-6-phosphatase in liver. The activities of Mg2+-ATPase in liver and acetylcholinesterase in brain were decreased under toxic doses of dieldrin. L-Ascorbic acid supplements in treated animals could partially prevent the pathological alterations, as observed histologically in liver and kidney tissues. Administration of this vitamin could also prevent alterations in some enzyme activities produced by toxic dieldrin doses.

Effect of dieldrin on rat liver plasma membrane enzymes

Dieldrin, an organochlorine insecticide, when administered orally to male albino rats at a dose of 5 mg/kg body weight/day for 15 days inhibits the enzyme Mg2+ -ATPase and stimulates the activity of 5'-nucleotidase and NADH-dehydrogenase in liver plasma membrane. L-ascorbic acid supplementation offers some protection in relation to the inhibition of Mg2+ -ATPase.

Role of the host in the chemotherapy of infectious diseases

The use of a washed-cell system to study the factors controlling the synthesis of alkaline phosphatase and neomycin by Streptomyces fradiae has shown that calcium and magnesium salts are stimulatory, with maximal synthesis of both achieved with a combination of these salts. Among all the carbon sources studied, only arabinose induces alkaline phosphatase synthesis, whereas glucose and other carbon sources inhibit the synthesis of the enzyme. Asparagine is a very good inducer of enzyme and neomycin synthesis, with lysine and alanine having lower stimulatory effects. The appearance of alkaline phosphatase is due to de novo protein synthesis as demonstrated by the inhibition of its synthesis in the presence of chloramphenicol. There is a good correlation between the synthesis of alkaline phosphatase and neomycin biosynthesis.