Cytokine response to the RSV antigen delivered by dendritic cell-directed vaccination in congenic chicken lines.

Systems of antigen delivery into antigen-presenting cells represent an important novel strategy in chicken vaccine development. In this study, we verified the ability of Rous sarcoma virus (RSV) antigens fused with streptavidin to be targeted by specific biotinylated monoclonal antibody (anti-CD205) into dendritic cells and induce virus-specific protective immunity. The method was tested in four congenic lines of chickens that are either resistant or susceptible to the progressive growth of RSV-induced tumors. Our analyses confirmed that the biot-anti-CD205-SA-FITC complex was internalized by chicken splenocytes. In the cytokine expression profile, several significant differences were evident between RSV-challenged progressor and regressor chicken lines. A significant up-regulation of IL-2, IL-12, IL-15, and IL-18 expression was detected in immunized chickens of both regressor and progressor groups. Of these cytokines, IL-2 and IL-12 were most up-regulated 14 days post-challenge (dpc), while IL-15 and IL-18 were most up-regulated at 28 dpc. On the contrary, IL-10 expression was significantly down-regulated in all immunized groups of progressor chickens at 14 dpc. We detected significant up-regulation of IL-17 in the group of immunized progressors. LITAF down-regulation with iNOS up-regulation was especially observed in the progressor group of immunized chickens that developed large tumors. Based on the increased expression of cytokines specific for activated dendritic cells, we conclude that our system is able to induce partial stimulation of specific cell types involved in cell-mediated immunity.

Is the anti-sarcoma and anti-viral cytokine "plasma factor" a novel chicken Y-box protein?

A line of research beginning in the early 1960s with the observation that West Nile virus and, later, several strains of rabies virus could inhibit the development of the Rous sarcoma virus-induced tumor in the wing-web of chicken (a "sarcoma-blockade") eventually culminated in the characterization of a 14-kDa circulating anti-sarcoma and anti-viral activity christened "plasma factor" (PF) which, unlike the interferons, inhibited the replication of diverse RNA-containing viruses, but not of any DNA-containing viruses. The possibility that this 14 kDa protein represented a novel antiviral cytokine has been strengthened by analysis of partial amino acid sequencing data which suggest that this 14-kDa cytokine may correspond to the 127-amino acid-long chicken YB2-like protein (Locus: XP_423576) deduced very recently from the genomic sequencing of chicken. Biologically, proteins of the Y-box family (such as chicken YB1 and YB2) not only bind DNA and thus regulate transcription but also bind single-stranded RNA in a sequence-specific and reversible manner, repress viral RNA translation, inhibit retroviral transformation of chicken fibroblasts, and are known to regulate transcription of human immunodeficiency virus and hepatitis B virus. Taken together, the available data point to a novel anti-viral cytokine with a novel mechanism of action.

v-src oncogene-specific carboxy-terminal peptide is immunoprotective against Rous sarcoma growth in chickens with MHC class I allele B-F12.

B(12) haplotype of the inbred chicken line CB (B12/B12) contains, like the bulk of chicken MHC(B) haplotypes, only a single dominantly expressed class I molecule (B-F). The peptide binding motifs for this major B-F12 molecule in chickens of Rous sarcoma regressor line CB (B12/B12) have been determined. Using stringent and relaxed motifs, several peptides were found in the v-src molecule of the PR-RSV-C, but most of these peptides are identical with that of endogenous c-src. Only the v-src C-tail peptide(517-524) (LPACVLEV) contains critical anchor amino acids (valine at positions 5 and 8) and shows a sequence different from the corresponding c-src peptide. This v-src C-tail peptide up-regulates expression of the B-F12 class I molecule on PBL, as assessed by FACS analysis, and stimulates T cell proliferation in a [3H]thymidine uptake assay. A protective effect of the immune response to LPACVLEV against RSV challenge was demonstrated in CB (B12/B12) chickens immunised with peptides encapsulated in liposomes.

DNA vaccination against v-src oncogene-induced tumours in congenic chickens.

DNA vaccination is particularly efficient for induction of cytotoxic T-lymphocyte (CTL) response. In our experiments, we used MHC(B) congenic chicken lines CB and CC (regressors and progressors of v-src-induced tumours, respectively) and a mutated, non-oncogenic v-src gene construct as the DNA vaccine. A high degree of vaccine protection against oncogenic v-src challenge was achieved in the CB line chickens. CTL response was demonstrated in vitro and by adoptive transfer of immune cells to the syngeneic host and to the CC line chickens rendered tolerant to CB cells. In the CC line chickens we observed tumour growth retardation after a low-dose DNA vaccination administered to immature recipients while higher amounts of DNA vaccine in immunocompetent chickens exerted an enhancing effect.

Protective effects of type I and type II interferons toward Rous sarcoma virus-induced tumors in chickens.

Growth of tumors induced by Rous sarcoma virus (RSV) is controlled by alleles at the major histocompatibility complex locus in chickens, indicating that immunological host defense mechanisms play a major role. We show here that the resistance phenotype of CB regressor chickens can be partially reverted by treating the animals with a monoclonal antibody that neutralizes the major serotype of chicken type I interferon, ChIFN-alpha. Injection of recombinant ChIFN-alpha into susceptible CC progressor chickens resulted in a dose-dependent inhibition of RSV-induced tumor development. This treatment was not effective, however, in CC chickens challenged with a DNA construct expressing the v-src oncogene, suggesting that the beneficial effect of type I interferon in this system resulted from its intrinsic antiviral activity and probably not from indirect immunmodulatory effects. By contrast, recombinant chicken interferon-gamma strongly inhibited tumor growth when given to CC chickens that were challenged with the v-src oncogene, indicating that the two cytokines target different steps of tumor development.

A recombinant fowlpox virus expressing the envelope antigen of subgroup A avian leukosis/sarcoma virus.

A recombinant fowlpox virus (FPV) was constructed by inserting cloned sequences from Schmidt-Ruppin subgroup A avian sarcoma virus coding for the viral envelope (env) antigen into a nonessential region of FPV DNA downstream from a synthetic promoter. Sera from chickens hyperimmunized with the recombinant FPV neutralized the infectivity of the homologous subgroup A virus (RCASBP/AP) but only weakly neutralized the infectivity of Rous sarcoma virus, another subgroup A avian leukosis virus. Similarly, vaccination of 1-day-old chicks with this recombinant FPV protected against infection with RCASBP/AP virus but not against infection with another subgroup A Rous-associated virus (RAV-1). These results show that such a recombinant FPV can be used to protect chickens against avian leukosis virus and confirm previous observations that a type-specific antigenic variability existed within the subgroup A avian leukosis/sarcoma virus group.

Vaccination with a low-oncogenic strain of Rous sarcoma virus prevents visceral tumors in chickens.

The oncogenic potential of different strains of Rous sarcoma virus (RSV) varies significantly in two Mhc(B) congenic chicken lines CB and CC and in their F1 hybrids with the unrelated inbred line IA. The Bryan high-titer pseudotype of RSV of antigenic subgroups D and B (BH-D, and BH-B) was highly oncogenic, eliciting mostly fatal, progressively growing tumors. Visceral tumor formation and erythroblastosis were seen after challenge with BH-B in CB and CC chickens, but not in their F1 hybrids with IA. Tumor regression induced by a low-oncogenic RSV strain PR-C elicited a protective immunity capable of preventing not only the progressive growth of challenge tumors at the site of inoculation, but also visceral tumor formation and erythroblastosis.

Avian retroviral recombinant expressing foreign envelope delays tumour formation of ASV-A-induced sarcoma.

An avian recombinant retrovirus expressing subgroup A envelope glycoprotein antigenicity, RAV-0-A1, significantly delayed sarcoma induction in chickens after challenge with ASV-A. When tumours were formed, significantly smaller tumours resulted. The mechanism of protection does not appear to be interference mediated, since virus was not detected in the chickens. Protection was correlated with both neutralizing and complement-dependent cytotoxic antibodies (CDCA).

Nonspecific immunoprotection against Rous sarcoma tumor in chicks.

An enzyme treated preparation of saprophytic Mycobacterium phlei, referred as NSI, when administered intramuscularly has been found to protect the chicks against Rous Sarcoma Virus induced tumor. A protection level of 35.4%, 24.1% and 21.2% were observed when challenged on 10th, 20th and 30th day post NSI inoculation. The tumor growth inhibitory-activity of NSI was significant (P less than 0.01). Both, systemic and intralesional administration of NSI exhibited significant tumorostatic activity (P less than 0.05). NSI stimulated the cell mediated immune response to specific as well as to nonspecific Rous sarcoma antigen. These studies indicated the immunopreventive activity of NSI against Rous sarcoma tumor which had an immunogenic basis.

Resistance of chickens to Rous sarcoma virus challenge following immunization with a recombinant avian leukosis virus.

An attenuated recombinant avian leukosis virus (ALV) produced by recombinant DNA techniques was examined for its ability to provide resistance to Rous sarcoma virus (RSV) challenge. Specific-pathogen-free chicken embryos (18-day incubation) and hatched chicks inoculated with recombinant ALV produced significantly smaller tumors than sham-inoculated controls upon challenge with RSV 2 weeks postinoculation; inoculation with RAV-1 produced similar results. Specific-pathogen-free hens inoculated with recombinant ALV produced viral-protein-specific antibody that was transmitted to 100% of the progeny, as detected by enzyme-linked immunosorbent assay. Progeny of the inoculated hens produced significantly fewer tumors than sham-inoculated controls upon challenge with RSV at hatch, indicating that maternal antibody may be a factor in resistance to tumor development.

[Virus-inhibiting properties of the carbonyl-conjugated pentaene roseofungin]. / Virusingibiruiushchie svoistva karbonil-kon'iugirovannogo pentaena rozeofungina.

The antiinfluenza activity of roseofungin, a polyenic macrolide antibiotic was studied in vitro on surviving fragments of the chick embryo chorionallantoic membranes and in ovo on growing chick embryos. It was shown that the antibiotic activity against influenza A and B viruses was sufficiently high. The activity of roseofungin against influenza A virus did not differ from that of remantadin, the most active inhibitor of influenza virus reproduction. However, the activity of roseofungin against influenza B virus was an advantage of this antibiotic over remantadin, which had practically no effect on this virus type. A statistically significant protective effect of roseofungin (p less than 0.05) was shown on the animals with experimental influenza. The study on the antiviral activity of roseofungin against the DNA-containing variolovaccine virus revealed that it markedly inhibited the plague reduction. Roseofungin had a pronounced inhibitory effect on cell neoplastic transformation induced by the RNA-containing oncogenic virus of Rous sarcoma.

[Para-immunity after oral antigen administration]. / Paramunität nach oraler Antigen-Applikation.

The term "Paramunity" summarizes all non-pathogen specific mechanisms of the defence against infections in man and animal, such as phagocytosis, interference, antibiosis, activation of the lymphopoietic cell system and of lysosomal enzymes, stimulation of humoral factors etc. Examples for the induction of a paramunity are described. After an oral or inhalatory administration of polyvalent vaccines prepared from inactivated bacteria to mice, the rate of phagocytosis of the peritoneal or alveolar macrophages increased significantly. An oral application of inactivated dyspepsia coli bacteria, caused in mice a partial protection against a challenge with a strain of Rous-sarcoma. After a tenfold oral paramunization with the polyvalent vaccine "Dodecoral" consisting of 12 heat-inactivated strains of enterobacteriaceae, mice were protected against an oral infection with the parapoliomyelitis virus Col-SK.

Effect of interferon on multiplication of avian sarcoma virus B77 in duck embryo fibroblasts.

The effect of interferon on the multiplication of the avian sarcoma virus B77 in duck embryo fibroblasts was studied. The interferon used for this purpose as induced in duck embryo fibroblasts by high multiplicities of reovirus serotype 3 (strain Dearing) and purified to a specific activity of at least 2 x 10(7) units/ml (estimated to be at least 10% pure). Treatment of duck embryo fibroblasts transformed with B77 virus with as little as 50 units/ml of this interferon caused a rapid inhibition of the release of virus particles, and a decrease in the specific infectivity of the virus particles that were released of about six-fold. The protein composition of virus particles released from normal and interferon-treated duck embryo fibroblasts was not detectably different. Examination of the nature of the virus-specified proteins, as determined by precipitation with specific antisera, synthesized at various times after treatment of transformed duck embryo fibroblasts with 300 units/ml of interferon revealed the following major changes: i. a more than 5-fold increase in the amount of a protein with a molecular weight of about 100,000 (P100) precipitated by antiserum to reverse transcriptase. This increase was paralleled by a decrease in the amount of the gag-pol precursors Pr190 and Pr180, but the amount of the alpha and beta subunits of reverse transcriptase was not altered by interferon treatment. ii. An at last 3-fold increase in the amount of cell-associated gag proteins. iii. A two- to ten-fold decrease in the amount of a protein with an apparent molecular weight of 76,000, in all likelihood Pr76, precipitated by antiserum to gp85. The primary cause of the interferon-induced inhibition of virus particle release appears to be inability of Pr76 to associate with gPr95/gp85 in plasma cell membranes.

A survey of non-specific cross-protective immunities induced by avian retroviruses.

Reticuloendotheliosis virus strain T (REV-T) induced immunity in chicks to challenge by representative subgroup members of the avian leukosis-sarcoma virus (ALSV) complex. Immunity levels were compared to determine the extent of antigenic relation between REV-T and the ALSV complex. Reciprocal studies using ALSV subgroup members and pheasant viruses as immunogens and REV-T as challenge were also performed. It was concluded that reciprocity of immunity is not equal between the viruses studied, nor is immunity directly related to the virus-neutralizing-antibody levels induced by immunization with the viruses studied. In some cases, the levels of cross-protection demonstrated may be a sign of the induction of antibodies to common or similar tumor-specific surface antigens rather than complete antigenic identity between REV-T and the ALSV members used; in others, virus-neutralizing antibodies may be a sign of partial identity between some proteins of REV-T and ALSV subgroup members.

Biohazards of investigations on the transmissible spongiform encephalopathies.

There is considerable current interest in the agents that cause the spongiform encephalopathies: scrapie, transmissible mink encephalopathy, kuru, and Creutzfeldt-Jakob disease (CJD). The unusual properties of these agents, their elusiveness, and their pathogenicity for humans (in the cases of kuru and CJD) make these agents interesting subjects of investigation but also make imperative a consideration of their potential biohazards in the laboratory. In view of both the potential pathogenicity of these agents and the potential hazards of many laboratory procedures, a series of physical containment levels, each of which corresponds to a range of composite risk factors, are suggested. The estimated composite risk factor used is a function of the potential pathogenicity or relative risk factor of the agent and the potential hazard of a laboratory procedure. The lowest risk factors (1 to 2+) correspond to levels of containment similar to those recommended by the Center for Disease Control for class II microorganisms, while the highest risk factors (5 to 8+) correspond to levels similar to those for class III microorganisms. The use of such a biohazard ranking system aids in a rational approach to selection of equipment and procedures.

Inhibitory effects of an aromatic retinoid (Ro 10-9359) on viral tumorigenesis.

Prophylactic treatment of hamsters and chickens with an aromatic retinoid (Ro 10-9359) inhibited Rous sarcoma virus (RSV) tumorigenesis. Retinoid administration to chickens with RSV-induced tumors resulted in tumor regression and/or confinement to the primary site. The retinoid also exerted a therapeutic effect on Shope virus papilloma development in the skin of rabbits.

BCNU and steroids in the viral-induced dog brain tumor.

Schmidt-Ruppin strain of Rous Sarcoma was inoculated intracerebrally into 27 newborn beagle dogs. Fourteen days after viral inoculation, 13 of the dogs were given intravenous BCNU (1 mg/kg). The other 14 were given the same volume of intravenous saline in a randomized, double-blinded fashion. Ninety percent of all dogs developed intracranial tumors. Radionuclide (mercury 197) brain scans were done on each dog at 2-week intervals. Median survival was 113 days in the BCNU group and 115 days in the placebo group (P > .99). Unequivocally positive radionuclide brain scans were detected in 5 dogs treated with BCNU and in 2 of the controls. There were no gross or microscopic differences at autopsy between treated and nontreated animals. BCNU, as given in this animal brain tumor model, did not demonstrate any oncolytic effect. An improvement in sequential brain scans was detected in 2 other dogs in response to Dexamethasone, which was given in a double-blinded, cross-over controlled fashion. Computerized tomography clearly demonstrated the tumor in two cases.

Chemical modification and immunogenicity of membrane fractions from mouse tumour cells.

A crude membrane fraction isolated from mouse tumour cells was treated with various chemicals. The effects on the immunogenicity of the membrane sample were tested in syngeneic mice for tumour protection, using a challenge dose of 10(5) viable tumour cells. Best protection was obtained after immunization of mice with a membrane sample modified with dimethylsulphate. Up to 60% of the animals remained tumour free, and the tumour-bearing animals showed a greatly increased mean survival time. The post-challenge sera contained no detectable amounts of cytotoxic antibodies. The membrane sample isolated from tumour cells which had been modified with dimethylsulphate showed less immunogenicity than the modified cells or the membrane fraction from unmodified cells.

Effects of prophylactic treatment with the methanol extraction residue fraction of tubercle bacilli (MER) on the development of Rous sarcomas of chickens following challenge with the Rous sarcoma virus.

Three-month-old chickens were treated with the methanol extraction residue fraction of tubercle bacilli (MER) under different conditions, and subsequently challenged with living Rous sarcoma virus. The birds developed progressively growing sarcomas following viral challenge. A substantial proportion of the hosts which had been pretreated with MER under optimal circumstances (38 to 58%) showed complete and long-lasting regression of the neoplasms, and the survival of many of the animals that did succumb to progressively growing tumors was prolonged. An absolute condition for prophylactic efficacy of MER treatment in this model system was injection of the agent into the same body area (wing) into which subsequent viral challenge was introduced. The quantity of MER employed and the timing of the prophylactic administration were also decisive variables.

Immunogenicity of tumour cells modified with various chemicals.

Mouse tumour cells were treated with various chemical modifiers. The number of modifying groups per cell was determined with labelled reagents. The effects of the different modifying groups on the immunogenicity of the tumour cells was tested in syngeneic mice for tumour protection using a challenge dose of viable cells at 1000 or 10,000 time LD100. Best protection was obtained after immunization of animals with tumour cells modified with dimethylsulphate or acetic anhydride, or with glutardialdehyde-fixed cells treated with a carbodiimide and methylamine. Up to 40% of the animals remained tumour-free. The other animals exhibited a greatly increased mean survival time. The post-challenge sera showed no detectable amounts of antibodies against the tumour cells.