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Biomedical subjects

T Mikami

Publications and source records attributed to T Mikami.

At least 451 records · Page 25Linked to original sources
PubMed1992

Detection of anti-gag antibodies of feline immunodeficiency virus in cat sera by enzyme-linked immunosorbent assay.

Using gag protein of feline immunodeficiency virus (FIV) expressed in Escherichia coli, an enzyme-linked immunosorbent assay (ELISA) system was developed for detection of antibodies to FIV gag protein in cat sera. With serum samples from cats experimentally infected with several strains and an infectious molecular clone of FIV, increases of the antibody titers to FIV gag protein were observed in all cases by the ELISA at early stage of infection. When we examined a total of 415 field cat sera which were previously tested by an indirect immunofluorescence assay (IFA), 9 (12.9%) out of 70 IFA positive sera were judged as negative by the ELISA. However, all 3 serum samples tested among the 9 IFA positive sera had antibodies to gp130 but not to p26 by a radioimmunoprecipitation assay. The results indicated that some IFA positive sera did not have antibodies to the p26 though they have antibodies to other proteins specific for FIV.

Animals↗
PubMed1992

Molecular characterization and heterogeneity of feline immunodeficiency virus isolates.

We have molecularly cloned the complete genomic DNA of TM2 strain of feline immunodeficiency virus (FIV) isolated in Japan and compared its nucleotide and the deduced amino acid sequence with those of previously described U.S. isolates, FIV Petaluma and FIV PPR. The infectious molecular clone of FIV TM2 is different from FIV Petaluma in host cell range; the clone can not infect Crandell feline kidney cells which were permissive for FIV Petaluma. The amino acid sequence homologies, in gag, pol, and env genes between FIV TM2 and Petaluma were 90%, 87%, and 81%, respectively. On the other hand, comparative analysis of each gene between FIV Petaluma and PPR showed 96,95, and 85%, respectively. These results suggested that the genomic diversity was present among FIV strains isolated from geographically distant areas. Interestingly, tat- and rev-like short open reading frames contained inframe stop codons in the FIV Petaluma but not in the FIV TM2.

Amino Acid Sequence↗
PubMed1992

Glycoprotein-specific immune response in canine herpesvirus infection.

Sera from dogs which were infected with canine herpesvirus (CHV) were analyzed for their serological reactivities against virus-specific glycoproteins (gps). By sequential immunoblot analysis using sera from experimentally infected dogs, it was found that the antibody response to gp 145/112 appeared first followed by responses to gp47 and gp80. In addition, all sera from naturally infected dogs which showed neutralizing activity to CHV reacted with gp 145/112, whereas 77% and 70% reacted with gp47 and gp80, respectively. Furthermore, some of the sera also cross-neutralized feline herpesvirus type 1 (FHV-1) and reacted with gp 143/108 of FHV-1, indicating that gp 145/112 of CHV induced cross-neutralizing antibody response to FHV-1.

Animals↗
PubMed1992

Expression of feline immunodeficiency virus gag gene in Escherichia coli.

The gag gene of a Japanese feline immunodeficiency virus (FIV) isolate, designated as FIV TM 2, was expressed in Escherichia coli as a fusion protein with TrpE. Using this expressed protein, an enzyme-linked immunosorbent assay was developed for detection of antibodies to FIV gag protein in feline sera. With serum samples from a cat experimentally infected with FIV, it was demonstrated that the period of seroconversion detected by this method corresponded to that by Western blotting.

Cloning, Molecular↗
PubMed1992

Synthesis of sulfonate analogs of bile acids.

Sulfonate analogs of C23 and C24 bile acids were synthesized from norcholic, norchenodeoxycholic, norursodeoxycholic, nordeoxycholic, norhyodeoxycholic, cholic, deoxycholic, hyodeoxycholic, and lithocholic acids. The principal reactions used were (1) reduction of the bile acids with NaBH4 to the corresponding bile alcohols, (2) selective tosylation of the terminal hydroxyl group, (3) iodination of the tosyl esters with NaI, and (4) treatment of the iodides with Na2SO3 to form the sulfonate analogs of the bile acids. The sulfonate analogs showed polarity similar to that of taurine-conjugated bile acids on thin-layer chromatography. The carbon 13 nuclear magnetic resonance spectral data for the sulfonate analogs were tabulated.

Bile Acids and Salts↗
PubMed1992

The restriction endonuclease map of Marek's disease virus (MDV) serotype 2 and collinear relationship among three serotypes of MDV.

A BamHI, EcoRI, and XhoI restriction endonuclease map of Marek's disease virus (MDV) serotype 2 (MDV2) DNA was constructed by double-digest analyses of 28 cloned BamHI and 11 cloned EcoRI fragments of MDV2 DNA, followed by hybridization tests of these cloned BamHI DNA fragments with electrophoretically separated digests of MDV2-infected cell DNA. On this map, MDV2 genome consisted of two segments which have unique regions inserted between two inverted repeat regions as observed in MDV serotype 1 and 3 genomes. Further, the DNA homology among three serotypes of MDV was examined by hybridization under less stringent conditions using cloned BamHI fragments of MDV2 DNA. Most of the MDV2 fragments located within the unique regions hybridized with MDV serotype 1 and 3 DNAs, indicating the presence of the collinear relationship among three serotypes. In addition, MDV2 DNA fragments which hybridized with the DNA fragments encoding MDV1 gp57-65 (or A antigen) or MDV1 gp100, gp60, gp49 (or B antigen) were identified and these fragments of serotypes 1 and 2 found to be collinear.

Animals↗
PubMed1992

Sequences within the feline immunodeficiency virus long terminal repeat that regulate gene expression and respond to activation by feline herpesvirus type 1.

We constructed a series of deletion mutants of feline immunodeficiency virus (FIV) long terminal repeat (LTR) to identify the regions that regulate gene expression and are responsive to trans-activation of FIV LTR by feline herpes-virus type 1 (FHV-1). We demonstrated that sequences between -124 and -79, and between -21 and -32 (relative to the cap site) are essential for gene expression of FIV in Felis catus whole fetus 4 (fcwf-4) cells. Further, we demonstrated that the sequence between -63 and -23 responds to trans-activation of FIV LTR by FHV-1 in fcwf-4 cells.

Animals↗
PubMed1992

Major core proteins, p24s, of human, simian, and feline immunodeficiency viruses are partly expressed on the surface of the virus-infected cells.

We have previously shown the expression of human immunodeficiency virus type 1 (HIV-1) major gag protein, p24, on the surface of persistently HIV-1-infected cells by using murine monoclonal antibodies (mAb). We now report that the cell surface gag p24 antigen expression is a universal phenomenon among HIV-1, simian immunodeficiency virus (SIV), and feline immunodeficiency virus (FIV). The mAbs prepared by immunization with purified HIV-1 particles were used as antibodies cross-reactive to HIV-1 and SIVagmp24 antigens. The mAbs to FIV p24 were raised against the gag precursor 50 kDa protein of FIV, which was expressed by Baculovirus vector. The p24 antigen expression on the cell surface was detectable in certain combinations of virus-host cell systems in all of these viruses. Since these p24 regions of the animal viruses seem to play as important a role in cell-mediated immunity as that of HIV-1, the p24 applicability as a candidate epitope for vaccine development could be evaluated in those animals.

Animals↗
PubMed1992

Production of feline immunodeficiency virus in feline and non-feline non-lymphoid cell lines by transfection of an infectious molecular clone.

An infectious molecular clone of the TM1 strain of feline immunodeficiency virus (FIV) was transfected into each of one feline (CRFK), two simian (COS and Vero) and two human (SW480 and HeLa) non-lymphoid cell lines, and virus production was assayed on feline T lymphoblastoid MYA-1 cells by monitoring reverse transcriptase activity. Infectious virus was produced in CRFK, Vero and HeLa cells, but not in COS and SW480 cells. When the basal promoter activity of the FIV long terminal repeat (LTR) was examined in these cell lines by using a chloramphenicol acetyltransferase assay, the activity correlated with the virus production in each cell line. Furthermore, when the activity of the FIV LTR was compared with those of three primate lentivirus LTRs, the highest activity in all the cell lines examined was produced by the LTR of simian immunodeficiency virus from African green monkey (SIVAGM), suggesting that it has a wide expression range. In COS and SW480 cells, the activity of the FIV LTR was much lower than that of the SIVAGM LTR. These results indicate that, whereas the primary block to FIV infection of certain cells may occur at the cell surface, the FIV LTR may also participate in controlling virus replication, as an intracellular mechanism.

Animals↗
PubMed1992

Highly conserved epitope domain in major core protein p24 is structurally similar among human, simian and feline immunodeficiency viruses.

Linear B cell epitopes were mapped on the major core protein p24 of human immunodeficiency virus type 1 (HIV-1), simian immunodeficiency virus (SIVAGM) and feline immunodeficiency virus (FIV) using a fusion protein-based method and murine monoclonal antibodies reactive against the p24 antigens expressed on the surface of HIV-1- and FIV-infected cells. The results suggest that the sites identified here are encoded at similar positions in the three virus genomes and consist of highly conserved epitopes, which could exhibit immunodominance.

Amino Acid Sequence↗
PubMed1992

Identification of a feline immunodeficiency virus gene which is essential for cell-free virus infectivity.

Feline immunodeficiency virus (FIV) contains at least three small open reading frames (ORFs) in the genome, in addition to the three structural genes. Two of these ORFs (putative vif and ORF-A) have unknown functions. Northern (RNA) blot analysis of mRNAs from an FIV-infected cell line showed that the putative-vif-specific mRNA was expressed as a 5.2-kb species. To examine the function of the putative vif gene, we constructed mutants carrying a deletion in either the vif-like gene or the rev gene from an infectious molecular clone of FIV. Although the vif mutant produced virion-associated reverse transcriptase at a normal level upon transfection, cell-free virus prepared from the transfected cells could not infect feline CD4+ cells. The infectivity of the vif mutant, however, was demonstrated in a coculture of the transfected cells and feline CD4+ cells. We conclude that FIV contains the vif gene, which is structurally and functionally similar to that of the primate lentiviruses.

Base Sequence↗
PubMed1992

Expression of the Marek's disease virus (MDV) homolog of glycoprotein B of herpes simplex virus by a recombinant baculovirus and its identification as the B antigen (gp100, gp60, gp49) of MDV.

A gene encoding a homolog of glycoprotein B of herpes simplex virus (gB homolog) has been identified on the Marek's disease virus (MDV) genome (L. J. N. Ross, M. Sanderson, S. D. Scott, M. M. Binns, T. Doel, and B. Milne, J. Gen. Virol. 70:1789-1804, 1989); however, the molecular and immunological characteristics of the gene product(s) are still not clear. In the present study, the gB homolog of MDV was expressed in insect cells by a recombinant baculovirus, and it was characterized to determine its molecular and antigenic properties. The expressed recombinant protein had three molecular sizes (88 to 110, 58, and 49 kDa) and was recognized by antisera from chickens inoculated with each of the three serotypes of MDV. By immunofluorescence analysis, it was shown that the protein was expressed in the cytoplasm and on the surface of the recombinant baculovirus-infected cells. The gB homolog of MDV was processed similarly to pseudorabies virus and varicella-zoster virus with respect to cleavage and the intramolecular disulfide bond between the cleaved products. Interestingly, the expressed protein reacted with monoclonal antibody M51, specific to the B antigen (gp100, gp60, gp49) of MDV, although the locations of the gene encoding the B antigen and of the gene encoding the gB homolog were reported to be different. Moreover, competitive experiments revealed that anti-gB homolog serum and monoclonal antibody M51 recognized the same molecules. From these results, the gB homolog and the B antigen of MDV seem to be the same glycoprotein.

Animals↗
PubMed1992

Altered cell tropism and cytopathicity of feline immunodeficiency viruses in two different feline CD4-positive, CD8-negative cell lines.

Two interleukin-2-dependent feline CD4-positive and CD8-negative cell lines, MYA-1 and the newly established FeL-039, were used as host cells for infection with feline immunodeficiency virus (FIV). All FIV strains used, the Petaluma strain and several new isolates, were highly cytopathic to MYA-1. In contrast, the kinetics of FIV replication in FeL-039 differed greatly depending on the strain tested, i.e., noninfectious strain, highly cytopathic strain, and less cytopathic strain producing a persistent state for a long period. It appears, therefore, that cell tropism for FIV differed with each FIV strain tested even in T-cell lines showing similar cell surface phenotypes. Cytopathicity of FIV is evidently due to both the FIV strain and the host T cell.

Animals↗
PubMed1992

Experimental models of acute and chronic sialoadenitis in the guinea pig.

Acute and chronic sialoadenitis were induced in ovalbumin-immunized guinea pigs by a single or repeated (once a day for 5 days) instillation of antigen into the parotid gland via the parotid duct. The acute sialoadenitis was characterized by infiltration of inflammatory polymorphonuclear leukocytes and the chronic one, by extensive tissue destruction together with infiltration of mononuclear leukocytes. In acute sialoadenitis, myeloperoxidase activity in the parotid gland, which was a marker of accumulation of neutrophils, was elevated, but in the chronic stage, it returned nearly to the control level. This observation is in accord with the histological findings that infiltrating cells in acute and chronic sialoadenitis were mainly polymorphonuclear and mononuclear leukocytes, respectively. Although cyclophosphamide suppressed the inflammation, both in acute and chronic sialoadenitis, indomethacin exerted its anti-inflammatory effect only in the acute stage. Our experimental models of acute and chronic sialoadenitis were easy to prepare, and had a high incidence. As the typical features of inflammatory development from acute to chronic phases were observed in these models, these models may be useful for studying the mechanism of the chronic course in immunologically induced inflammation and the effects of drugs on each phase and the chronic course of inflammation.

Acute Disease↗
PubMed1992

Monoclonal antibodies to feline lymphocyte membranes recognize the leukocyte-common antigen (CD45R).

By immunization of BALB/c mice with a feline T lymphoblastoid cell line, MYA-1 cells, two types of lymphocyte-specific monoclonal antibodies (mAbs) were obtained. The 220/205/190 kd protein defined by 2F11 mAb is highly expressed on the surface of MYA-1 cells and another feline T lymphoma cell line, FL74 cells. The protein is also expressed on normal feline thymocytes, splenocytes and feline peripheral blood mononuclear cells (PBMCs). Another mAb, 17B10, caused similar results as those of 2F11 except for its low reactivity with FL74 cells. The second type of mAb, 15B3, defined the 220 kd protein. The reactivities of this mAb with MYA-1 cells, FL74 cells, PBMCs and feline splenocytes were lower than the former two mAbs, and did not react to feline thymocytes. On the other hand, 17B10 and 15B3 defined partial populations of MYA-1 and FL74 cells recognized by 2F11. The cells defined by the 2F11 and 17B10 are all leukocytes in spleen and lymph node. In contrast, 15B3 defined most of the cells in B cell area and partially in T cell area. These results suggested that 2F11 and 17B10 recognized the specific antigen of 220/205/190 kd of the leukocyte-common antigen (L-CA) family, CD45R, with different epitopes, and that 15B3 defined the distinct antigen of 220 kd on CD45R.

Animals↗
PubMed1992

A new rat mutant with chronic conjugated hyperbilirubinemia and renal glomerular lesions.

A new mutant strain of inbred Sprague Dawley rats with autosomal recessive hyperbilirubinuria, were studied by biochemical, histologic, and ultrastructural methods. The plasma bilirubin concentration in the homozygote was significantly higher than that of the heterozygote, and about 80% of the bilirubin was conjugated. Plasma BSP and ICG clearance were both severely delayed in the homozygote. Plasma BSP elimination kinetics suggested that the pathophysiologic defect was not hepatic uptake or storage but rather in secretion into bile. Histopathology of the liver demonstrated brown pigment in the hepatocytes that appeared to be lipofuscin. The electron microscopic features of the hepatic pigment resembled those of the Dubin-Johnson syndrome. Homozygote histopathology also revealed glomerular lesions with mesangial expansion and proliferation in the kidneys. Immunohistologic studies disclosed mesangial granular deposition of IgG, IgA, and to a lesser degree, IgM and C3. These renal changes resembled those of IgA nephropathy. The spontaneous hyperbilirubinuric rat (EHBR) may be a useful animal model for studying constitutive conjugated hyperbilirubinemia, bilirubin metabolism, cholestasis, and glomerulonephropathy subsequent to hepatic dysfunction.

Animals↗