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K A Schat

Publications and source records attributed to K A Schat.

At least 19 recordsLinked to original sources
PubMed2005

Classification of Marek's disease viruses according to pathotype: philosophy and methodology.

The concept of pathotype in Marek's disease (MD) probably dates from the recognition of a more virulent form of the disease in the late 1950s (Benton & Cover, 1957). Distinctions between MD virus strains were further expanded with the description of the vv pathotype in the early 1980s and of the vv+ pathotype in the 1990s. Pathotype designations reflect important biological properties that correlate with the break-through of vaccinal immunity in the field. However, pathotyping methods applied by various laboratories have not been uniform, preventing critical comparison of results. Better uniformity of pathotyping procedures is desirable.The Avian Disease and Oncology Laboratory (ADOL) method is based on induction of lymphoproliferative lesions in vaccinated chickens. This method has been used to pathotype more than 45 isolates and is the basis for the current pathotype classification of MD virus strains. Its limitations include requirements for a specific type of chickens (15x7 ab+), large numbers of animals, and a statistical method to compare lesion responses to those of JM/102W and Md5 control strains. Because of these limitations, it has not been and is not likely to be used in other laboratories. Comparability in pathotyping can be improved by the comparison of field isolates with standard prototype strains such as JM/102W, Md5 and 648A (American Type Culture Collection) or their equivalents. Data may be generated by different in vivo procedures that measure tumour induction, neurological disease (both neoplastic and non-neoplastic lesions), or solely non-neoplastic criteria (such as lymphoid organ weights or virus replication). Methods based on neoplastic criteria, especially when generated in MD-immunized chickens, will probably correlate most closely with that of the ADOL method and be most relevant to evolution of MD virus in the field. Based on data from several trials, a modification of the ADOL method that utilizes fewer chickens and can be conducted with commercial specific pathogen free strains is proposed. The modified method is based on "best fit" comparisons with prototype strains, and is expected to provide results generally comparable with the original method. A variety of other alternative criteria (see earlier) are also evaluated both for primary pathotyping and as adjuncts to other pathotyping methods. Advantages and disadvantages of alternative methods are presented.

Animals↗
PubMed2005

Isolation of Marek's disease virus: revisited.

Splenocytes from chickens infected with low-passage stocks of Marek's disease virus (MDV) RB-1B, a very virulent (vv) strain and vv+ RK-1 were used to compare the efficacy of chick kidney cells (CKC), chicken embryo fibroblasts (CEF) and chicken embryo kidney cells (CEKC) for virus isolation. CKC were superior to CEF and CEKC. MDV foci were present at 4 days post infection in CKC but not until 6 days post infection in CEF or CEKC. Virus yield was higher in CKC than in CEF or CEKC at 6 days post infection. Passage of RB-1B in CKC yielded a significantly higher virus increase than with CEF or CEKC. The same was true for RK-1 comparing CKC with CEKC. Interestingly, RK-1-infected CEF were negative or had very low number of foci in passage 1, but virus yield increased 500-fold to 600-fold on passage in CKC, CEF, and CEKC. Recommendations on procedures for successful virus isolation are provided.

Animals↗
PubMed2004

Detection of chicken anemia virus in the gonads and in the progeny of broiler breeder hens with high neutralizing antibody titers.

Previous evidence for the presence of chicken anemia virus (CAV) in the gonads of immune specific-pathogen-free chickens raised the question whether this occurs also in commercial breeders. The presence of CAV was investigated by nested PCR in the gonads and spleens of hens from two 55- and 59-week-old, CAV-vaccinated (flocks 2 and 3), and two 48- and 31-week-old non-vaccinated broiler breeder flocks (flocks 1 and 4). In addition, lymphoid tissues of 20-day-old embryos from these hens were also investigated for the presence of CAV. CAV was detected in the gonads and of 5/6 and 11/22 of the vaccinated hens and in some hens also in the spleen alone. Embryos from 7/8 and 5/18 of these hens were positive. In the non-vaccinated flocks, CAV was detected in the gonads of 11/34 and 10/10 hens in flocks 1 and 4, respectively. In addition, 11 birds in flock 1 had positive spleens. CAV DNA was detected in 3/11 and 2/10 of their embryos. CAV-positive gonads and embryos were detected in samples from hens with moderate as well as high VN antibody titers. Vaccinated chickens positive for CAV in the gonads and in their embryos had VN titers ranging from >1:512 to <1:2048. In non-vaccinated chickens, the VN titers of CAV positive chickens ranged from 1:128 to 1:4096. These results demonstrate that CAV genome can remain present in the gonads of hens in commercial broiler breeder flocks even in the presence of high neutralizing antibody titers that have been associated with protection against CAV vertical transmission. It also suggests that transmission to the progeny may occur irrespectively of the level of the humoral immune response in the hens.

Animals↗
PubMed2004

Chicken infectious anemia virus: an example of the ultimate host-parasite relationship.

Chicken infectious anemia virus (CIAV) is a resistant and ubiquitous virus of chickens causing disease in young chickens and immunosuppression in all birds. This paper reviews the current knowledge of CIAV with a focus on new findings indicating that immunosuppressive effects have not been fully appreciated, especially as they relate to the development of antigen-specific cytotoxic T cells. A more complete understanding of the immunosuppressive effects of CIAV emphasizes the need for better vaccines, especially for the broiler industry. In addition, a new model is proposed for the control of viral replication in the reproductive tract of specific-pathogen-free chickens, which may be latently infected. This model suggests that virus transcription is controlled by viral enhancer and repressor elements, which are regulated by different hormones. As a consequence, CIAV has a well-adapted relationship with its host, avoiding immune detection, ensuring passage of virus to the next generation, and eliciting limited pathology to the host.

Animals↗
PubMed2002

Interactions of poult enteritis and mortality syndrome-associated reovirus with various cell types in vitro.

An avian reovirus, ARV-CU98, has recently been isolated from poults experiencing poult enteritis and mortality syndrome (PEMS). To further understand ARV-CU98 and its role in PEMS, the current study investigates interactions of ARV-CU98 with various cell types in vitro. When macrophages, B cells, T cells, and liver cells of chicken or turkey origin were co-incubated with ARV-CU98, only cells of liver origin demonstrated cytopathic effects, the presence of viral antigen, and reduced metabolic activity over time. Furthermore, distinctive pockets of viral particles were evident in electron microscopic examination of a chicken hepatocellular carcinoma (LMH) cell line, but not in a chicken macrophage cell line (MQ-NCSU) co-incubated with virus. Additional evidence of viral replication in LMH, cells but not MQ-NCSU cells was demonstrated by the presence of two viral bands (43 and 145 kD size) in cell lysates from LMH cells exposed to ARV-CU98. Although not capable of being infected by ARV-CU98, MQ-NCSU cells do appear to be activated by the virus since IL-1 mRNA expression is increased in MQ-NCSU cells 2 h after addition of the virus. LMH cells exposed to the virus demonstrate a decrease in IL-1 mRNA expression by 8 to 10 h after addition of the virus, perhaps corresponding to the initiation of infection by the virus. In conclusion, this study demonstrates that ARV-CU98 actively infects and replicates in LMH cells, but not in lymphocytes or macrophages, suggesting that the liver may be a target and site of replication of ARV-CU98 in poults experiencing PEMS.

Animals↗
PubMed2001

Cellular responses in chickens treated with IFN-alpha orally or inoculated with recombinant Marek's disease virus expressing IFN-alpha.

Mammalian type I interferons (IFN-alpha/beta) are potent mediators of innate antiviral immune responses, in particular through enhancement of natural killer (NK) cell cytotoxicity. Recently, chicken IFN-alpha (ChIFN-alpha) has been identified and shown to ameliorate Newcastle disease virus (NDV) infection when given to chickens at relatively high concentrations in the drinking water. In this report, the effect of recombinant ChIFN-alpha (rChIFN-alpha) on NK cell cytotoxicity was examined using (51)Cr-release assays. NK cell cytotoxic activity was also analyzed following inoculation with attenuated Marek's disease virus (MDV) serotype 1 strain R2/23 and a recombinant MDV (parent strain R2/23)-expressing ChIFN-alpha [rMDV(IFN-alpha)]. Treatment of chickens with high doses of rChIFN-alpha in the drinking water significantly decreased NK cell cytotoxicity compared with untreated chickens over a 7-day period. Inoculation of chickens with R2/23 significantly decreased NK cell cytotoxicity as well, whereas the rMDV(IFN-alpha) had no effect on NK cell cytotoxicity. Treatment of chicken embryo cell cultures with rChIFN-alpha inhibited replication of the very virulent MDV RB-1B strain in vitro, and oral treatment of chickens with rChIFN-alpha reduced MDV R2/23 replication in vivo.

Administration, Oral↗
PubMed2000

Expression of cytokine genes in Marek's disease virus-infected chickens and chicken embryo fibroblast cultures.

The role of cytokines in the pathogenesis and immunity of Marek's disease (MD), a herpesvirus-induced T-cell lymphoma in chickens, is poorly understood. Two different experiments were used to examine the potential role of particular cytokines in the pathogenesis and immune responses of MD. First, chicken embryo fibroblasts (CEF) were stimulated with lipopolysaccharide (LPS) and/or recombinant chicken interferon-gamma (rChIFN-gamma) and used to develop techniques for examining transcription of IFN-alpha, IFN-gamma, inducible nitric oxide synthase (iNOS), interleukin (IL)-1beta, IL-2, IL-6 and IL-8 by reverse transcription-polymerase chain reaction (RT-PCR). Addition of LPS and/or rChIFN-gamma resulted in the up-regulation of mRNA for iNOS, IL-1beta and IL-6, while IFN-gamma was up-regulated by LPS alone. IL-2 was down-regulated by the treatments. Second, to determine the effects of Marek's disease herpesvirus (MDV) infection on cytokine transcription in vivo, chickens were infected with MDV at 21 days of age and examined at 7 days post-infection (p.i.) (exp. 1) or were infected with MDV at 1 day of age and examined from 3 to 15 days p.i. (exp. 2). In MDV-infected chickens, IFN-gamma transcription was up-regulated as early as 3 days p.i. until the termination of the experiment at 15 days p.i., while iNOS and IL-1beta were up-regulated between 6 and 15 days p.i. Infection of 1-day-old chicks increased levels of mRNA for IFN-gamma and iNOS between 16- and 64-fold at 9 days p.i. These results suggest that IFN-gamma and iNOS may play an important role in the pathogenesis of MD.

Animals↗
PubMed2000

Distribution of chicken anaemia virus in the reproductive tissues of specific-pathogen-free chickens.

The specific-pathogen-free (SPF) flocks of chickens maintained by the Department of Microbiology and Immunology at Cornell University became infected, inadvertently, with chicken anaemia virus (CAV), as demonstrated by seroconversion. Chickens from five flocks representing three different strains were examined for the presence of CAV using nested PCR. Virus was detected in ovaries, infundibula, vas deferentia, testes and spleens. Ovaries were positive in 38 to 72% of the hens in four flocks with 13 to 56 birds examined per flock. Interestingly, the ovaries were often the only positive tissues, while a few hens had only positive spleens. In roosters, the vas deferens was positive in 30 to 79% of the birds with 5 to 19 birds examined per flock; the vas deferens was the only positive tissue in 20 to 37%. Individual cells in the theca externa and rare epithelial cells in the infundibular epithelium were positive for CAV by in situ PCR. Positive cells were not detected in testes or vas deferentia. The SH-1 strain of CAV was isolated from these tissues and partially sequenced. Only minor sequence differences were found compared to CIA-1 and Cux-1. Embryos from matings between persistently infected dams and sire had CAV-positive cells in mesenchyme near the developing vertebral column. The data show that CAV persists in the reproductive tissues far longer than previously thought, and that it can be vertically transmitted from persistently infected birds.

Amino Acid Sequence↗
PubMed2000

Transactivation of latent Marek's disease herpesvirus genes in QT35, a quail fibroblast cell line, by herpesvirus of turkeys.

The QT35 cell line was established from a methylcholanthrene-induced tumor in Japanese quail (Coturnix coturnix japonica) (C. Moscovici, M. G. Moscovici, H. Jimenez, M. M. Lai, M. J. Hayman, and P. K. Vogt, Cell 11:95-103, 1977). Two independently maintained sublines of QT35 were found to be positive for Marek's disease virus (MDV)-like genes by Southern blotting and PCR assays. Sequence analysis of fragments of the ICP4, ICP22, ICP27, VP16, meq, pp14, pp38, open reading frame (ORF) L1, and glycoprotein B (gB) genes showed a strong homology with the corresponding fragments of MDV genes. Subsequently, a serotype 1 MDV-like herpesvirus, tentatively name QMDV, was rescued from QT35 cells in chicken kidney cell (CKC) cultures established from 6- to 9-day-old chicks inoculated at 8 days of embryonation with QT35 cells. Transmission electron microscopy failed to show herpesvirus particles in QT35 cells, but typical intranuclear herpesvirus particles were detected in CKCs. Reverse transcription-PCR analysis showed that the following QMDV transcripts were present in QT35 cells: sense and antisense meq, ORF L1, ICP4, and latency-associated transcripts, which are antisense to ICP4. A transcript of approximately 4.5 kb was detected by Northern blotting using total RNA from QT35 cells. Inoculation of QT35 cells with herpesvirus of turkeys (HVT)-infected chicken embryo fibroblasts (CEF) but not with uninfected CEF resulted in the activation of ICP22, ICP27, VP16, pp38, and gB. In addition, the level of ICP4 mRNA was increased compared to that in QT35 cells. The activation by HVT resulted in the production of pp38 protein. It was not possible to detect if the other activated genes were translated due to the lack of serotype 1-specific monoclonal antibodies.

Animals↗
PubMed2000

Inhibitory effects of nitric oxide and gamma interferon on in vitro and in vivo replication of Marek's disease virus.

The replication of Marek's disease herpesvirus (MDV) and herpesvirus of turkeys (HVT) in chicken embryo fibroblast (CEF) cultures was inhibited by the addition of S-nitroso-N-acetylpenicillamine, a nitric oxide (NO)-generating compound, in a dose-dependent manner. Treatment of CEF culture, prepared from 11-day-old embryos, with recombinant chicken gamma interferon (rChIFN-gamma) and lipopolysaccharide (LPS) resulted in production of NO which was suppressed by the addition of N(G)-monomethyl L-arginine (NMMA), an inhibitor of inducible NO synthase (iNOS). Incubation of CEF cultures for 72 h prior to treatment with rChIFN-gamma plus LPS was required for optimal NO production. Significant differences in NO production were observed in CEF derived from MDV-resistant N2a (major histocompatibility complex [MHC], B(21)B(21)) and MDV-susceptible S(13) (MHC, B(13)B(13)) and P2a (MHC, B(19)B(19)) chickens. N2a-derived CEF produced NO earlier and at higher levels than CEF from the other two lines. The lowest production of NO was detected in P2a-derived CEF. NO production in chicken splenocyte cultures followed a similar pattern, with the highest levels of NO produced in cultures from N2a chickens and the lowest levels produced in cultures from P2a chickens. Replication of MDV and HVT was significantly inhibited in CEF cultures treated with rChIFN-gamma plus LPS and producing NO. The addition of NMMA to CEF treated with rChIFN-gamma plus LPS reduced the inhibition. MDV infection of chickens treated with S-methylisothiourea, an inhibitor of iNOS, resulted in increased virus load compared to nontreated chickens. These results suggest that NO may play an important role in control of MDV replication in vivo.

Aging↗
PubMed1998

Cytotoxic T lymphocyte response in chickens immunized with a recombinant fowlpox virus expressing Marek's disease herpesvirus glycoprotein B.

Previously, we demonstrated that cytotoxic T lymphocytes (CTLs) from MHC: B19B19 and MHC: B21B21 chickens inoculated with a non-oncogenic Marek's disease virus (MDV) vaccine strain, SB-1/12 can lyse syngeneic reticuloendotheliosis virus (REV)-transformed cell lines expressing MDV pp38 or gB genes. In this study, we report the characterization of MDV gB-specific CTLs in chickens immunized with recombinant fowlpox virus expressing MDV gB gene (rFPV-gB). Spleen cells from rFPV-gB inoculated chickens (MHC: B19B19), depleted for CD4+, CD8+, TCR gamma delta+, TCR alpha beta 1+ or TCR alpha beta 2+ cells were used as effector cells in chromium release assays. Effector cells depleted of CD8+ or TCR alpha beta 1+, but not CD4+, TCR gamma delta+ or TCR alpha beta 2+ markedly reduced the percentage of specific release (%SR). Compared to the %SR caused by the SB-1/12-sensitized CTLs, the %SR caused by rFPV-gB-sensitized CTLs was low, but statistically significant. This is a first report on the induction of MDV gB-specific CD8+ CTLs in chickens immunized with rFPV-gB vaccine.

Animals↗
PubMed1998

Open reading frame L1 of Marek's disease herpesvirus is not essential for in vitro and in vivo virus replication and establishment of latency.

Two mutant CV1988 Marek's disease virus (MDV) strains were developed in which a part of ORF L1 was replaced by lacZ with the SV40 early promoter. These mutant strains, CVIL1LacZ-A and -B, were inoculated into chickens to test the hypothesis that ORF L1 is involved in the induction and/or maintenance of latency. Mutant virus could be reisolated from lymphocytes obtained from chickens during both the lytic and latent phase of infection, indicating that ORF L1 is not essential for the induction and/or maintenance of latency or the reactivation from latency. Beta-galactosidase-positive lymphocytes were detected during the latent infection demonstrating that the SV40 early promoter can be active in recombinant MDV strains during latent infection. Although the insertion of lacZ was stable in cell culture, recombination within lacZ and the BamHI-L fragment was observed during in vivo infection.

Animals↗
PubMed1997

Characterization of Marek's disease herpesvirus-specific cytotoxic T lymphocytes in chickens inoculated with a non-oncogenic vaccine strain of MDV.

Previously we have reported that reticuloendotheliosis virus (REV)-transformed cell lines expressing Marek's disease virus (MDV) genes pp38, meq or gB were lysed by syngeneic MDV-specific splenocytes from major histocompatibility complex (MHC):B9B19 and MHC:B1B21 chickens. In contrast, REV-transformed cell lines expressing the MDV gene ICP4 were only lysed by syngeneic MDV-specific splenocytes from MHC:B21B21 chickens. In this study we report that this syngeneic cell-mediated immune response is induced by cytotoxic T lymphocytes (CTL). Splenocytes from MDV vaccine strain, SB-1 inoculated MHC:B19B19 and MHC:B21B21 chickens, depleted for CD4+, CD8+, TCR gamma delta +, TCR alpha beta 1+ and/or TCR alpha beta 2+ cells, were used as effector cells in chromium-release assays. Effector cells depleted of CD8+ or TCR alpha beta 1+, but not TCR gamma delta + or TCR alpha beta 2+, markedly reduced the MDV-specific release. Depletion of CD4+ effector cells did not influence the specific release significantly. This is the first report on identification of virus-specific CD8+ CTL in chickens inoculated with a non-oncogenic vaccine strain of MDV.

Animals↗
PubMed1996

Syngeneic Marek's disease virus (MDV)-specific cell-mediated immune responses against immediate early, late, and unique MDV proteins.

Marek's disease (MD) infection has been controlled effectively by vaccination using nononcogenic and/or attenuated oncogenic Marek's disease virus (MDV) vaccines. Thus far, there is little knowledge on the role of cell-mediated immune (CMI) responses during MDV infection or vaccination. To elucidate the importance of MDV proteins in CMI responses, the pp38, Meq, ICP4, or ICP22 genes of an oncogenic strain, GA and the gB, ORF A, A41, or L1 genes of a highly oncogenic strain, RB1B were stably transfected into reticuloendotheliosis virus (REV)-transformed lymphoblastoid cells, CU-91 (MHC: B19B19) and CU-205 (MHC: B21B21). Cell lines positive for MDV gene transcription and/or protein expression were used in a standard 4-hr chromium release assay. Effector cells for this assay were obtained from splenocytes of chickens infected with the oncogenic strain, JM-16/13 or the nononcogenic vaccine strain, SB-1/12. Cell lines expressing MDV pp38, Meq, or gB were lysed by syngeneic but not allogeneic MDV-sensitized splenocytes obtained from chickens of B19B19 and B21B21 haplotypes. However, syngeneic CMI responses against ICP4 were detected only in B21B21 chickens. CMI responses were not detected against B19B19 and B21B21 cell lines expressing A41, L1, ORF A, or ICP22. This report suggests that syngeneic CMI responses against pp38, Meq, ICP4, and gB of GA and RB1B strains, respectively, can be induced in chickens inoculated with JM16/13 or SB-1/12. The difference in CMI response to ICP4 in genetically susceptible (B19B19) and genetically resistant (B21B21) chickens may be an important factor in genetic resistance.

Animals↗
PubMed1996

A hypervariable region in VP1 of chicken infectious anemia virus mediates rate of spread and cell tropism in tissue culture.

Chicken infectious anemia virus (CIAV) is a unique infectious agent with an amino acid composition that has been found to be remarkably conserved even in isolates from different parts of the world. We have characterized field isolates of CIAV which vary significantly in terms of their abilities to replicate in culture, demonstrating a biological difference between isolates. Two sublines of MDCC-MSB1 cells that differ in their abilities to support CIAV were identified. In the MSB1(S) subline the CIA-1 isolate of CIAV was found to be less cytopathogenic than the prototype Cux-1(C) isolate; the MSB1(L) subline, which supports Cux-1(C) replication, was found to be nonpermissive for CIA-1. Alignments of the VP1 sequences of previously examined isolates with those of the field isolates CIA-1 and L-028 and the culture-adapted ConnB isolate revealed a previously unreported hypervariable region spanning amino acid positions 139 to 151. Chimeras of Cux-1(C) and CIA-1 were constructed to examine the potential for this region to affect cytopathogenicity. Transfer of a 316-bp region of Cux-1(C) open reading frame 1 into CIA-1 produced a virus with a cytopathogenic profile typical of Cux-1(C), indicating that one or both of the amino acid differences at positions 139 and 144 affect the rate of replication or the spread of infection. Transfection experiments with additional chimeras indicated that the inability of CIA-1 to replicate in MSB1(L) cells is mediated by a larger region of the genome which contains the hypervariable region in addition to upstream amino acid differences. Analysis of chimeras excluding the entire region of open reading frame 1 suggested the presence of a secondary mediator in the progression of infection in culture that was localized to a region containing a single nucleotide difference which results in amino acid differences in both VP2 (V-153) and the nuclear localization signal of VP3 (C-118). Immunofluorescence assays indicated an increased cytoplasmic distribution of VP3 and a general lack of VP3-associated apoptotic bodies in infections of CIA-1 and chimeras containing V-153 or C-118, as opposed to a primarily nuclear distribution and association with well-formed apoptotic bodies in Cux-1(C)-infected cells.

Amino Acid Sequence↗
PubMed1994

Enhanced expression of the Marek's disease virus-specific phosphoproteins after stable transfection of MSB-1 cells with the Marek's disease virus homologue of ICP4.

Phosphoprotein pp38, coded for by the BamHI-H fragment of the Marek's disease herpesvirus (MDV) genome is expressed in tumor cells and tumor cell lines. pp38 is associated with two other phosphoproteins, pp41 and pp24, and can be detected in a small percentage of tumor cells by indirect immunofluorescence assays (IIFA). The importance of MDV ICP4 for the regulation of pp38 expression was examined in the following MSB-1-derived cell lines stably transfected with the selection plasmid pNL1 [MDCC-CU221 (CU221)], pNL1 and the BamHI-A fragment of MDV DNA containing ICP4 (CU224), MDV ICP4 inserted in antisense direction in the eukaryotic expression vector pXT1 (CU222), or ICP4 in sense direction in pXT1 (CU223) or cotransfected with pNL1 and EcoRI-linearized BamHI-A MDV DNA (CU225, -237, -243, -244). IIFA analysis showed that CU223 had a markedly increased expression of pp38, while CU224 had a slightly increased expression. No changes were noted in CU221 or CU222, while expression of pp38 was decreased in CU225, -237, -243, and -244. Radioimmunoprecipitation assays demonstrated that the expression of all three phosphoproteins was enhanced in CU223. Steady-state transcriptional analysis showed that CU223 had increased levels of pp38-specific (1.9 and 3.3 kb) and ICP4-specific (10.0 kb) transcripts.

Animals↗
PubMed1994

Characterization of Marek's disease virus BamHI-A-specific cDNA clones obtained from a Marek's disease lymphoblastoid cell line.

A cDNA library was constructed from poly(A)+ RNA fractions obtained from a Marek's disease (MD) lymphoblastoid cell line, MDCC-CU41, in which viral gene expression is very limited. Three independent groups (1, 2, and 3) of MD virus (MDV)-specific clones were obtained, which were mapped in the inverted repeat region of the BamHI-A fragment of the MDV genome. Northern blot analysis showed that probes prepared from these cDNA clones hybridized with several transcripts of different sizes in poly(A)+ RNA of MDCC-CU41, although the amounts of these transcripts were relatively small compared to those in MDV lytically infected cells. Moreover, a small open reading frame, which can encode a 94-amino-acid protein, was identified in the A41 cDNA clone (Group 3). By RNase protection assays, the 1.2-kb Group 3 transcriptional unit has been defined. In indirect immunofluorescent antibody assays, antiserum against the bacterially expressed fusion protein, glutathione S-transferase-A41, reacted specifically with the cytoplasmic regions of MDV (strain RB1B)-infected chick kidney cells. However, MDCC-CU41 did not contain a detectable level of the protein determined by these methods.

Amino Acid Sequence↗