Virus replication and high-titered interferon production in human leukocyte cultures inoculated with Newcastle disease virus

The Enhancing Effects of 10% PBS Washout of Holocene Minerals on HuIFN-αN3 Inducing Capacity of NDV ZG1999HDS or Sendai virus (Cantell Strain)

Different strains of Newcastle disease viruses (NDV) or Sendai viruses (SV) are used to induce the production of human leukocyte multi subtype interferon-alpha (HuIFN-αN3). Their inducing capacity can be enhanced in different ways. One includes 10% PBS washout of Holocene minerals (HM). The presented study aims to compare the HuIFN-αN3 inducing capacity of NDV ZG1999HDS or SV (Cantell strain) strain in vitro, and to evaluate the enhancing effect of 10% PBS washouts of HM on both viruses. The NDV strains’ ZG1999HDS interferon inducing capacity (483.23 ± 4.5 pg/mL) was similar to that of the SV (Cantell strain) (584.16 ± 5.9 pg/mL). It was shown that the HuIFN-αN3 inducing capacity of the strain of NDV ZG1999HDS can be strongly enhanced with 10% PBS washout of HM to 3818.21 ± 41.9 pg/mL and 4790.34 ± 33.5 pg/mL with SV (Cantell strain), u. The RP-HPLC analyses of such HuIFN-αN3 induced with the strain of NDV ZG1999HDS show the difference to SV (Cantell strain) induced HuIFN-αN3 in the absence of subtype α14 and the lower level of the subtype α1. The possible ways of such enhancement were also studied and it was postulated that the Fe²⁺ ions from 10% PBS washouts of HM, while stimulating the reactive oxygen species (ROS) and nitric oxide (NO) formation, activate the transcription factor NF- κB and consequently the production of HuIFN-αN3.

Transient activation of the PI3K/Akt pathway promotes Newcastle disease virus replication and enhances anti-apoptotic signaling responses

Viral infection activates a host's cellular phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway, which is involved in cell differentiation, growth, survival, and apoptosis. To elucidate molecular mechanisms in the pathogenesis of Newcastle disease virus (NDV), we demonstrated that NDV transiently activates the PI3K/Akt pathway in chicken cells at an early phase of infection. Its activation was observed as early as 15 min post-infection and gradually weakened after 24 h. Incubating cells with a PI3K inhibitor, LY294002 or wortmannin, prior to NDV infection decreased NDV progeny yields and suppressed Akt phosphorylation at early times post-infection. Akt activation is triggered by NDV-GM or NDV-F48E9 and is abolished by methyl β-cyclodextrin and chlorpromazine. Treatment following NDV-La Sota infection had no obvious effect. However, inhibiting PI3K activation promoted apoptotic responses during an early stage of NDV infection. The pan caspase inhibitor ZVAD-FMK mitigated the reduction in Akt phosphorylation by inhibiting PI3K activation, which indicates the signaling pathway promotes cell survival and, in turn, facilitates viral replication. By suppressing premature apoptosis upon NDV infection, the PI3K/Akt pathway enhances the anti-apoptotic response.

The role of interferons in early pregnancy

The interferons (IFNs) form part of the large family of glycoproteins known as cytokines. They are secreted by host cells as a line of defence against pathogens and certain tumours. IFNs affect cell proliferation and differentiation and also play a very important role in the functioning of the immune system. Miscarriage in both humans has been associated with higher levels of IFN, particularly IFN-γ. However, this cytokine is evidently vital in successful murine pregnancies since it is involved in maintaining the decidual layer in addition to remodelling of the vasculature in the uterus. The effects of IFN on human pregnancies are more difficult to study. Hence, there is still a lot more to be discovered in the hope of reaching a definite conclusion regarding the impact of IFN.

A strategy for high-level expression of soluble and functional human interferon alpha as a GST-fusion protein in E. coli

Escherichia coli is the most extensively used host for the production of recombinant proteins. However, most of the eukaryotic proteins are typically obtained as insoluble, misfolded inclusion bodies that need solubilization and refolding. To achieve high-level expression of soluble recombinant human interferon alpha (rhIFNalpha) in E. coli, we have first constructed a recombinant expression plasmid (pGEX-hIFNalpha2b), in which we merged the hIFNalpha2b cDNA with the glutathione S-transferase (GST) coding sequence downstream of the tac-inducible promoter. Using this plasmid, we have achieved 70% expression of soluble rhIFNalpha2b as a GST fusion protein using E. coli BL21 strain, under optimized environmental factors such as culture growth temperature and inducer (IPTG) concentration. However, release of the IFN moiety from the fusion protein by thrombin digestion was not optimal. Therefore, we have engineered the expression cassette to optimize the amino acid sequence at the GST-IFN junction and to introduce E. coli preferred codon within the thrombin cleavage site. We have used the engineered plasmid (pGEX-Delta-hIFNalpha2b) and the modified E. coli trxB(-)/gor(-) (Origami) strain to overcome the problem of removing the GST moiety while expressing soluble rhIFNalpha2b. Our results show the production of soluble and functional rhIFNalpha2b at a yield of 100 mg/l, without optimization of any step of the process. The specific biological activity of the purified soluble rhIFNalpha2b was equal to 2.0 x 10(8) IU/mg when compared with the WHO IFNalpha standard. Our data are the first to show that high yield production of soluble and functional rhIFNalpha2b tagged with GST can be achieved in E. coli.

Growth of malignant rabbit fibroma virus in lymphoid cells

To understand better the immunosuppressive capacity of malignant rabbit fibroma virus (MV), we characterized MV growth in lymphoid cells. Replication of MV occurs in unstimulated normal spleen cells in vitro and is enhanced by adding T- or B-lymphocyte mitogens. In splenic T-lymphocyte preparations, comparable results are found: virus growth in the absence of mitogen, augmented by adding Con A. Unlike mature T cells, thymic lymphocytes support MV replication only when mitogen is added. When spleen cells from rabbits infected with MV in vivo are removed and cultured without mitogen, MV growth is again observed, with virus titer increasing about 10-fold per day of culture. In spleen cell populations from MV tumor-bearing rabbits, MV grows best in T lymphocytes, moderately in B lymphocytes, and least efficiently in adherent cells. When spleen cells are examined immediately following sacrifice, MV antigens are expressed solely on T lymphocytes from rabbits infected in vivo with MV 7 days previously. However, following overnight incubation in vitro a population of non-T lymphocytes displays cell membrane virus antigens. MV adapts itself somewhat to growth in lymphocytes, showing significantly greater growth in lymphocytes following passage in lymphocytes than is observed for non-lymphocyte-propagated virus. MV-infected lymphocytes also elaborate a factor that enhances MV growth in lymphocytes. Thus, MV replicates preferentially in mature T lymphocytes but will grow well in B cells as well. In vivo infection produces relatively small amounts of recoverable virus. However, when these lymphocytes are cultured in vitro virus replicates very well without added mitogens. These growth patterns may help to understand MV-induced immunologic dysfunction.

Human lymphocyte production of corticotropin and endorphin-like substances: association with leukocyte interferon

Human leukocyte interferon (hIFN-alpha) preparations contain immunologically and biologically recognizable endorphin and corticotropin-like (ACTH-like) activities. The ACTH bioactivity was demonstrable only after pepsin or acid treatment. Highly purified hIFN-alpha was composed of two molecular species of interferon (18,500 and 23,000 daltons). Endorphin activity was associated with both of these molecules. Pepsin treatment of the 23,000-dalton but not the 18,500-dalton hIFN-alpha generated ACTH activity. In acid, the 23,000-dalton hIFN-alpha broke down into the 18,500-dalton form and ACTH (4500 daltons). The ACTH derived from hIFN-alpha by pepsin digestion comigrated with a purified ACTH standard in NaDodSO4/polyacrylamide gel electrophoresis. hIFN-alpha-producing lymphocytes showed positive immunofluorescence after staining with highly specific antisera to ACTH alpha-(1-13) and gamma-endorphin. Essentially 100% of the human peripheral lymphocytes were capable of producing both ACTH and gamma-endorphin-related substances, presumably associated with hIFN-alpha. These results strongly suggest a circuit between the immune and neuroendocrine systems which involves neuroendocrine hormone-like substances, some of which are associated with hIFN-alpha

Replication of poliovirus and measles virus in cultures of human lymphoblastoid and of Burkitt lymphoma cell lines

Poliovirus type 1 replicated in 4 different human lymphoblastoid cell lines (LBL) transformed in vitro by EBV virus or isolated from cases of mononucleosis. Maximum virus titers were reached 2--4 days after inoculation. There was a decrease in percentage of viable cells in the infected cultures but a considerable fraction of cells was not destroyed by virus replication. A persistent low grade replication of virus was observed and demonstrable during 56 days after inoculation in one LBL cell line. Presumably a small fraction of cells supporting virus replication is continuously recruited from refractory cells. No virus propagation was demonstrable in 4 Burkitt lymphoma (BL) cell lines. Measles virus grew efficiently in both types of cell lines. Using indirect immunofluorescent technique poliovirus and measles virus antigen could be demonstrated in the cytoplasm of LBL cells in parallel with disappearance of F-actin containing microvilli.

Interaction between 6/94 virus, a parainfluenza type 1 strain, and unstimulated mouse lymphocytes

6/94 virus was found to grow in unstimulated splenic mouse lymphocytes depleted of monocyte macrophages. Both egg-grown virus and virus produced in mouse macrophage cultures induced the development of hemadsorption and the appearance of new infectious virus in the lymphocyte cultures. An antigenic relative. Sendai virus, on the contrary, was quickly inactivated in these lymphocyte cultures, in agreement with previous reports in the literature. The T lymphocyte population seemed to be the fraction principally involved in the replication of 6/94 virus. The immunization of mice with 6/94 virus and the appearance of high levels of humoral neutralizing antibodies did not inhibit completely the susceptibility of their lymphocytes to the infectious agent.

Human leukocyte interferon: production, purification to homogeneity, and initial characterization

A method of fractionating proteins by high-performance liquid partition chromatography has been developed and used for isolation and purification to homogeneity of one of the species of human leukocyte interferon. The homogeneous interferon exhibited a sharp peak on high-performance liquid chromatography and a single narrow band on sodium dodecyl sulfate/polyacrylamide gel electrophoresis in the presence of 2-mercaptoethanol. Extraction of the gel gave a single sharp peak of antiviral activity coinciding with the protein band. The specific activity of pure interferon was found to be 2--4 X 10(8) units/mg, based on amino acid analysis. The molecular weight is 17,500--18,000.

Human leukocyte interferon purified to homogeneity

One of the species of human interferon produced by incubation of leukocytes with Newcastle disease virus was purified to homogeneity. It exhibited one peak of activity coinciding with a single protein band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

Mechanisms of recovery from Herpesvirus infections -a review

A variety of specific immunological mechanisms have been shown to be effective at neutralizing herpesviruses or destroying herpesvirus infected cells. These include both humoral and cell mediated immune responses or combinations thereof. Thus, it is genarlly accepted that humoral immunity is probably responsible for preventing reinfection whereas cellular immunity, mediated by T lymphocytes or by the interaction of antibody and Fc receptor bearing cells, is more important in recovery from infections. In addition to these specific responses to herpesvirus infection, a number of nonspecific cellular and humoral components have been shown to inhibit the progression of virus replication and therefore, have been implicated in assisting the host in the recovery process. The various interactions and counteractions between the various nonspecific and specific components of the immune response are discussed with respect to their role in recovery from both primary and recurrent disease as well as how they may eventually be manipulated so as to control herpesvirus recrudescent disease.

Neutrophils are mediators of antiviral immunity

The paper presents evidence that polymorphonuclear neutrophils upon stimulation with herpesvirus-induced antigens release a material inhibitory to virus infection. The material does not appear to be identical to type I or II interferon.

Experimental infection of human leukocytes with parainfluenza 1 (6/94) virus

Parainfluenza 1 (6/94) virus replicated in both unstimulated and phytohemagglutinin (PHA)-stimulated human peripheral blood leukocytes (PBL). After exposure of PBL to 6/94 virus at a multiplicity of infection of 1, the presence of viral antigen was demonstrated by immunofluorescence in the cytoplasm of less than 1% of unstimulated PBL and 1 to 5% of macrophages. Small amounts (less than 50 mean egg infective doses per ml in most instances) of cell-free virus were present in 18 of 30 (60%) cell cultures tested from 3 to 8 days postinfection. Cell-free virus peaked 6 days postinfection. Virus replication was enhanced in PHA-stimulated cells. Approximately 1 to 10% of PHA-stimulated PBL contained viral antigen as evidenced by immunofluorescence, and cell-free virus was present in 19 of 25 (76%) of the cell cultures tested from 3 to 8 days postinfection. Paramyxovirus nucleocapsids and tubular aggregates were seen in the cytoplasm of approximately 5% of PHA-stimulated PBL and were visualized only in lymphocytes. No other unusual intracytoplasmic or intranuclear structures were seen.

Studies on the capacity of human tonsillar lymphocyte subpopulations to produce interferon

Tonsillar lymphocytes produced classical interferon (Type I) in response to NDV infection and produced immune interferon (Type II) in response to PHA, PPD or histo-incompatible antigens. Lymphocytes having higher specific gravity and having a greater proliferative response to mitogens or antigens produced more interferon than lymphocytes having lower specific gravity. There was no difference between heavy and light small tonsillar lymphocytes in regard to their sensitivity to the protective effects of interferon. As for the interferon produced in association with a cellular immune response, the peak of interferon production tended to appear earlier than the peak of 3H-TdR incorporation. It is suggested that tonsillar lymphocytes play an important role in human host defense against virus infections.

Antibody-dependent cellular protection against herpes simplex virus dissemination as revealed by viral plauqe and infectivity assays

Mouse nonimmune peripheral blood lymphocytes (PBL) plus antibody to herpes simplex virus inhibited virus dissemination in herpes simplex virus-infected 3T3 cell culture as revealed by development of viral plaque, size of immunofluorescent foci, appearance of polycaryocytes, and viral infectivity appearing in the culture. These nonimmune PBL did not act alone in inibiting virus dissemination, but did act synergistically in combination with antibody. The ratio of PBL to target monolayer cells needed to produce this effect was 20. Splenic lymphocytes had weak activity, whereas thymocytes were without effect, even in the presence of antibody. Neither interferon nor lymphotoxin was detected in this lymphocyte-mediated response. These findings support previous observations, based on cytotoxicity assays, that antibody-dependent cellular immune processes could be important in control of and recovery from herpesvirus infection.

Interferon in Breast Cancer

The interferon production ability by leukocytes in vitro from 37 patients with mammary cancer was studied. The leukocytes were derived from patients between 27 and 80 years of age, 6 months and up to 28 years after removal of the primary tumor. The interferon titer of 34/37 human breast cancer leukocytes was 2–8 times lower than that of 35 normal donor leukocytes and 3 non-neoplastic diseases. No correlation between interferon titers, the patient's age, and the histologic tumor features was observed; however, interferon production was observed to return to normal in those patients who had a long remission period or whose tumors were locally confined. Interferon response of patients under different therapy was modified: radiotherapy affected interferon production more severely than chemotherapy. A tendency for association between the skin DNCB test and interferon response was found. An inverse correlation was observed between interferon titers and the PHA-induced transformation index.

Induction of interferon in ovine and human lymphocyte cultures by mycoplasmas

Mycoplasma pneumoniae, Acholeplasma laidlawii, M. arthritidis, and M. pulmonis were shown to induce interferon in the lymphocyte fraction of ovine peripheral blood leukocytes, but not in the polymorphonuclear leukocyte fraction. Human peripheral blood lymphocytes produced significant levels of interferon in response to infection with M. pneumoniae and M. synoviae. The antiviral substance induced by the mycoplasmas in human lymphocytes was characterized as interferon by the usual criteria.

Produção de interferon ou substância semelhante em culturas EB3 inoculadas com soros humanos contendo antígeno Austrália

Culturas de células EB3, quando inoculadas com soros humanos contendo antígeno Austrália, produzem interferon ou substância semelhante em títulos significativamente mais elevados do que as culturas controle, não inoculadas. As culturas de células EB3 inoculadas com soros humanos negativos para o antígeno Austrália comportam-se de modo idêntico às culturas controle, no que respeita aos títulos de interferon, ou substância semelhante. Sugere-se a possibilidade daquele efeito poder servir de indicador de uma possível interação entre as células EB3 e o antígeno Austrália.

Human interferon therapy for herpes zoster in adults

Of 37 patients with herpes zoster 28 were treated with human exogenous interferon and 9 received only culture medium. The interferon was produced in leukocyte cultures and was given intramuscularly in one daily dose of 1 million units for 5-8 days. In the interferon-treated patients interferon was detectable in serum (peak level 1-5 hours after interferon injections) and in vesicle fluid, and in some patients also in urine samples. Anti-interferon antibodies were not found. Of the 28 interferon-treated patients 8 had a slight temperature increase and 4 showed a transient local reaction. In the interferon treated group of patients the duration of pain was shortened and the development of crust formation was enhanced compared with the control group.

Dye uptake assay: an efficient and sensitive method for human interferon titration

Currently, human interferon (IF) assays are generally performed by plaque reduction or visual cytopathic effect methods. Both are time-consuming, subjective in interpretation, and, in the case of the latter, relatively insensitive. An adaption of the dye uptake method for human IF titration which uses foreskin-derived fibroblasts and vesicular stomatitis virus is described. This assay is reproducible and sensitive (1 unit = 3 international units). By direct comparison, however, it is somewhat less sensitive than the plaque reduction assay (1 unit = 1.1 international units). This assay is especially recommended for use in needed clinical investigations of human IF because of its technical simplicity, allowing efficient handling of large numbers of specimens.

Interferon Induction by the Psittacosis Agent in Guinea Pig Leukocyte Cultures

High titers of interferon were induced by the psittacosis agent in guinea pig leukocyte cultures. Optimal yields of interferon were produced from freshly prepared guinea pig leukocyte cultures containing 4 × 10 6 cells per ml inoculated with a psittacosis/cell multiplicity of 1.0 and incubated at 35 C for 24 hr. Leukocytes obtained from 2- to 4-month-old guinea pigs produced 20 times more interferon than leukocytes from 3- to 4-week-old animals. The biological activity of interferon and the kinetics of its production from psittacosis-infected guinea pig leukocyte cultures were similar to those reported for virus-induced leukocyte interferons.

Transfer of interferon-producing macrophages: new approach to viral chemotherapy

Mice were protected from infection with Semliki Forest virus and encephalomyocarditis virus by the transfer of peritoneal macrophages that were stimulated to produce interferon in vitro by exposure to a nonreplicating virus. This method of therapy was also utilized in animals infected with encephalomy-ocarditis virus after onset of clinical signs. Of these animals 40 percent recovered, but only 9 percent of the control group recovered.

A plaque assay for enumerating antigen-sensitive cells in delayed-type hypersensitivity

A general method is described for enumerating antigen-sensitive lymphocytes obtained from individuals having delayed hypersensitivity, in this case from highly tuberculin-sensitive guinea pigs. The method is based on the observation that resting lymphocytes are generally unable to support replication of RNA viruses, whereas antigen-"activated" lymphocytes can. Lymph node lymphocytes from individual animals were cultured in the presence or absence of tuberculin purified protein derivatives (PPD). After various periods of time, the cells were infected either with Newcastle disease virus or vesicular stomatitis virus, and plated in agar over a monolayer of cells susceptible to the virus. Wherever a lymphocyte yielded infectious virus, a discrete plaque in the monolayer could be seen. The increase in plaques of the antigen-stimulated cells over the background of the control sample was taken as the number of antigen-sensitive cells in the population. When lymphocytes from normal guinea pigs or from guinea pigs immunized to produce only circulating antibody to PPD were similarly tested, no increase in plaque-forming units (PFU) was observed. The average increase in PFU due to antigenic stimulation varied from 1 per 1000 lymphocytes at 24 hr to 16 per 1000 lymphocytes at 96 hr. By employing inhibitors of mitosis (colchicine, vinblastine, and thymidine) it was evident that the increase in PFU at least up to 48 hr was primarily due to initial antigen-reactive cells and not their progeny.

Interferon response of lymphocytes in disorders with decreased resistance to infections

Interferon production was induced by Sendai and Newcastle disease virus in blood obtained from patients with Down's syndrome (eight cases), Fanconi's anaemia (one case), subacute sclerosing panencephalitis (one case), blast cell leukaemia (nine cases), chronic lymphocytic leukaemia (six cases) and control subjects. The titres per millilitre of blood varied greatly, but the interferon response per lymphocyte was comparatively constant in all groups with the exception of chronic lymphocytic leukaemia, where the cells displayed a markedly reduced interferon-producing ability.