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C J Gauntt

Publications and source records attributed to C J Gauntt.

At least 37 records · Page 2Linked to original sources
PubMed1991

Anti-Coxsackievirus B3 neutralizing antibodies with pathological potential.

Adolescent CD-1 mice inoculated with coxsackievirus B3 (CVB3m) will develop acute myocarditis with focal lesions by 7 days post-inoculation (p.i.). Administration of murine sera containing anti-CVB3m-neutralizing antibodies into CVB3m-inoculated mice at 3 days p.i. will exacerbate myocarditis, suggesting the presence of pathological antibodies. To study potential pro-inflammatory properties of virus-induced antibodies, a panel of anti-CVB3m-neutralizing monoclonal antibodies (mAbs) was generated. Several studies demonstrated shared epitopes between CVB3m particles and cultured murine cardiac or neonatal skin fibroblasts: (1) one or more mAbs bound to cultured cardiac fibroblasts; (2) several mAbs can participate in complement-mediated lysis of neonatal skin fibroblasts; and (3) at least one mAbs stimulated synthesis of a macrophage chemoattractant from cultured neonatal skin fibroblasts. Injection of one mAb in three doses, each of about 5 micrograms, into adolescent male CD-1 mice induced focal myocarditic lesions which were similar to CVB3m-induced lesions. One mAb induced a diffuse interstitial hypercellularity in most mice and two mAbs did not induce detectable cardiopathology. These data suggest that some anti-CVB3m neutralizing idiotypes (antibodies) which initially can provide protection via virus clearance mechanisms can also bind to cross-reacting epitopes on normal tissues. Binding of antibodies to normal heart tissues could stimulate proinflammatory reactions by several mechanisms and sustain myocarditis.

Animals↗
PubMed1991

Autoimmune determinants of rheumatic carditis: localization of epitopes in human cardiac myosin.

Rheumatic carditis is a sequela of group A streptococcal throat infection. Although the pathogenic mechanisms which lead to heart damage in acute rheumatic fever (ARF) are not well understood, autoimmune processes have been implicated, involving molecular mimicry between streptococci and the human heart. We have studied the immunological cross-reactions between the group A Streptococcus and human heart to understand their molecular and immunological basis. Human and mouse monoclonal antibodies (mAb) and affinity-purified anti-myosin antibodies from acute rheumatic fever sera were characterized and shown to cross-react with group A streptococcal M protein and myosin. Studies of proteolytic fragments of human cardiac myosin identified sites of cross-reactivity in the rod region of the myosin heavy chain. Murine monoclonal antibodies cross-reactive with streptococcal M protein and myosin recognized epitopes located in the S2 and light meromyosin (LMM) subfragments of the heavy chain. None of the cross-reactive monoclonal antibodies recognized the S1 subfragment. One broadly cross-reactive monoclonal antibody was highly cytotoxic for heart cells in vitro and reactive with the LMM fragment. The data suggest that the cross-reactive epitopes recognized by these antibodies are conformational, dependent upon their alpha-helical structures, and potentially damaging to host tissues.

Antigens, Bacterial↗
PubMed1991

Differential effects of myocarditic variants of Coxsackievirus B3 in inbred mice. A pathologic characterization of heart tissue damage.

The histopathologic features reflecting the influence of virus genotype and host differences on myocarditis were evaluated in six inbred mouse strains (C57BL/6, B10.D2, BALB/c, DBA/2, A/J, and C3H/HeJ) inoculated with four respective variants of coxsackievirus B3 (CVB3-CG, -SH, -ST, or -NR). The most severe and most prevalent histologic lesions occurred after infection with CVB3-SH or -CG variants, regardless of mouse strain. In general, C57BL/6 mice showed the lowest susceptibility to myocarditis while A/J or C3H/HeJ animals had the highest susceptibility, whether early (7 days) or late (21 days) after CVB3 inoculation. Lesion size and calcification depended to an extent on disease severity, but calcification in the C3H/HeJ myocardium was notably sparse. Lesions clustered distinctly in the midthird of the ventricular wall in some animals, particularly in DBA/2 mice. Extensive pericarditis occurred exclusively in BALB/c and DBA/2 animals and predominated over the right ventricle anterolaterally. Virus titer in the heart did not account for disease susceptibility among mouse strains. These characteristics reflect differences in pathogenicity and are important considerations in the study of mechanisms in CVB3-induced myocarditis in mice.

Animals↗
PubMed1990

Molecular detection and identification of enteroviruses using enzymatic amplification and nucleic acid hybridization.

Analysis of enteroviral genomes has revealed that the 5' nontranslated region is highly conserved, providing consensus sequences for the design of oligonucleotides which should anneal to most, if not all, human enteroviral RNAs. We designed and used a pair of such generic primers to enzymatically amplify cDNA from coxsackievirus group B types 1 through 6, poliovirus types 1 through 3, 4 coxsackievirus A types, and 29 echoviruses. The polymerase chain reaction (PCR) products generated with these enteroviral primers were analyzed by agarose gel electrophoresis, Southern blotting, or slot blot hybridization. A genotype-specific PCR was used to detect coxsackievirus B3, to the exclusion of other enteroviruses, by using a coxsackievirus B3 genome-specific primer pair that was derived from sequences coding for part of a capsid protein. A technique is demonstrated by which individual genotypes, for which no sequence information is known, can be identified by high-criterion hybridization analysis following amplification with generic enterovirus PCR primers.

Base Sequence↗
PubMed1990

Echovirus 22 is an atypical enterovirus.

Although echovirus 22 (EV22) is classified as an enterovirus in the family Picornaviridae, it is atypical of the enterovirus paradigm, typified by the polioviruses and the coxsackie B viruses. cDNA reverse transcribed from coxsackievirus B3 (CVB3) RNA does not hybridize to genomic RNA of EV22, and conversely, cDNA made to EV22 does not hybridize to CVB3 genomic RNA or to molecular clones of CVB3 or poliovirus type 1. EV22 cDNA does not hybridize to viral RNA of encephalomyocarditis virus or to a molecular clone of Theiler's murine encephalomyelitis virus, members of the cardiovirus genus. The genomic RNA of EV22 cannot be detected by the polymerase chain reaction using generic enteroviral primers. EV22 does not shut off host cell protein synthesis, and the RNA of EV22 is efficiently translated in vitro in rabbit reticulocyte lysates. Murine enterovirus-immune T cells recognize and proliferate against EV22 as an antigen in vitro, demonstrating that EV22 shares an epitope(s) common to enteroviruses but not found among other picornaviruses.

Animals↗
PubMed1987

Murine natural killer cells limit coxsackievirus B3 replication.

Previous indirect evidence suggested that natural killer (NK) cells play a role in coxsackie virus B3 serotype 3, myocarditic variant (CVB3m)-induced myocarditis by limiting virus replication. In this study, we present direct evidence that NK cells can limit CVB3m replication both in vitro and in vivo. Virus titers are lowered in primary murine neonatal skin fibroblast (MNSF) cultures incubated with activated splenic large granular lymphocytes (LGL) taken from mice 3 days postinoculation of CVB3m, a time of maximal NK cell activity. The antiviral effect of this cell population is diminished by complement-mediated lysis with the use of anti-asialo GM1 antiserum but not with anti-Lyt-2 monoclonal antibody. Neither interferon nor anti-CVB3m-neutralizing antibody was detected in these cultures. Although activated LGL initiate lysis within CVB3m-infected MNSF in vitro within 3 hr of addition, they do not lyse uninfected MNSF cultures. CVB3m replication is required for expression of surface changes on MNSF that result in lysis by NK cells because cell cultures treated with compounds that prevent CVB3m replication are not killed by LGL. LGL also do not lyse MNSF cultures inoculated with UV-inactivated virus. Mice inoculated with activated LGL and subsequently challenged with CVB3m had reduced titers of virus in heart tissues in comparison to titers of CVB3m in heart tissues of mice not given LGL. The antiviral activity of the LGL preparation was abolished by prior treatment with anti-asialo GM1 antiserum plus complement but not by prior treatment with anti-Lyt-2 monoclonal antibody and complement. These data suggest that NK cells can specifically limit a nonenveloped virus infection by killing virus-infected cells.

Animals↗
PubMed1987

In situ immune autoradiographic identification of cells in heart tissues of mice with coxsackievirus B3-induced myocarditis.

In adolescent CD-1 male mice inoculated with a myocarditic coxsackievirus B3 (CVB3m) acute focal lesions containing necrotic myocytes, infiltrating mononuclear cells, and fibroblasts develop. With the use of an in situ immune autoradiographic method with rat monoclonal antibodies (MAb) and an 35S-labeled antibody, viral antigens were detected outside of lesions. Macrophages, T lymphocytes, and natural killer (NK) cells were identified within myocarditic lesions during the acute phase of the disease. Macrophages detected by anti-Mac-1 MAb were in focal areas within myocarditic lesions on Days 4-7 after inoculation. T lymphocytes were detected in myocarditic lesions on Days 4-10, with MAb to Thy-1 and Lyt-1 antigens showing diffuse reaction patterns, suggesting random distribution of these cells in lesions. Focal areas of reactivity were detected with MAbs to L3T4 and Lyt-2 antigens, suggesting clusters of helper and cytotoxic/suppressor T lymphocytes, respectively. NK cells were presumptively detected by asialo GM1 surface marker in lesions at all times. The presence of activated NK cells in lesions was confirmed by assay of mechanically dissociated heart tissues on Day 8. These data describe the temporal sequence and identity of leukocytes entering into CVB3-induced focal myocarditic lesions during the acute phase of disease in CD-1 mice.

Animals↗
PubMed1986

Involvement of natural killer cells in coxsackievirus B3-induced murine myocarditis.

The role of natural killer cells in the temporal development of coxsackievirus B3-induced myocarditis in adolescent CD-1 male mice was examined. Inoculation of purified CVB3m induced maximum NK cell activity in the splenic populations at 3 days postinoculation (p.i.) as assessed by lysis of YAC-1 cells; maximum virus titers in heart tissues were also found at day 3 p.i. Mice depleted of NK cells after injection of anti-asialo GM1 antiserum i.v. had decreased NK cell activity, increased CVB3m titers in heart tissues, and exacerbated myocarditis. Although lesion number was not increased in heart tissues of the latter mice, lesions in these mice exhibited increased myocyte degeneration and dystrophic calcification above that found in lesions of mice inoculated with CVB3m only. No alteration in interferon titers were observed in CVB3m-infected mice treated with anti-asialo GM1 antiserum as compared with normal CVB3m-infected mice. Measurements of splenic NK cell activity in mice inoculated with doses of 10(2) to 10(8) PFU of CVB3m per mouse or UV-irradiated virus suggest that replication of CVB3m is required for NK cell activation. An amyocarditic variant of CVB3m (ts5R) was shown to replicate in heart tissues and to elicit NK cell activity comparable to that elicited by CVB3m. Therefore, the data suggest that NK cell activation depends on virus replication and that these cells provide some protection against CVB3m-induced myocarditis by limiting virus replication in heart tissues.

Animals↗
PubMed1986

Coxsackievirus group B replication in cultured fetal baboon aortic smooth muscle cells.

All six coxsackievirus B (CVB) serotypes replicated to various extents in fetal baboon aortic smooth muscle cells (SMC) in culture. CVB3 and CVB4 replicated to the highest titers and induced no cytopathology at the level of light microscopy. Maximum yields of CVB3 were produced between 12 and 24 hr postinoculation. Up to 15% of SMC cells became infected, as determined by immunofluorescence assays with anti-CVB3 antiserum, yet overall cell division in infected cultures did not differ from infected SMC cultures. Electron microscopy of CVB3-inoculated SMC cultures revealed changes in some cells: viruslike particles, secondary lysosomes containing dense bodies, and peripheral nuclear chromatin condensation. CVB3 replicated well in SMC passages up to the eighth, but did not replicate in eleventh-passage cells. Because of the cardiotropic and myotropic potential of this virus and its ability to replicate in aortic SMC with associated ultrastructural alterations, CVB3 (and other CVB) should be further examined as an etiologic agent(s) that could induce atherosclerosis.

Animals↗
PubMed1986

Coxsackievirus B3 infection alters plasma membrane of neonatal skin fibroblasts.

Replication of coxsackievirus B3 occurred for days in cultures of murine neonatal skin fibroblasts in the absence of cytopathology and resulted in alteration of the plasma membrane. Dual immunofluorescence studies showed that the lectin Ulex europaeus agglutinin I bound only to cells producing viral capsid antigens. Cultures of coxsackievirus B3-inoculated murine neonatal skin fibroblasts showed maximum binding of this lectin at 72 h postinoculation. These data show that in a nonlytic infection a picornavirus can alter the surface of an infected cell.

Animals↗
PubMed1986

Effects of viral infection on contraction of the diaphragm in mice.

Isometric contractile properties of isolated phrenic nerve-diaphragm muscle preparations were used to study the effects of picornavirus infections on diaphragm muscle function. Properties of muscles from virus-inoculated and control mice were similar during brief contractions. However, when subjected to a series of fatiguing contractions by indirect or direct stimulation, muscles of mice inoculated with a paralytic variant of encephalomyocarditis (EMC) virus showed a greater rate of fatigue and a reduced capacity to recover from fatigue than did muscles from uninoculated control mice or muscles from mice inoculated with a nonparalytic coxsackievirus B3 (CVB3). Mice paralyzed by EMC virus infection had high titers of virus in the brain and similar titers of virus in diaphragm muscle as found in diaphragm muscles of CVB3-inoculated mice. The results indicate that EMC virus infection of mice leads to increased fatigability of the diaphragm muscle and that there are both neural and muscular components of this enhanced fatigue.

Animals↗
PubMed1985

Cellular immune responses in mice challenged with an amyocarditic variant of Coxsackievirus B3.

An amyocarditic variant of a temperature-sensitive (ts) mutant derived from the parent myocarditic variant Coxsackievirus B3 (CVB3m) was studied in a murine model of CVB3m-induced myocarditis to assess virus-induced antigens and their possible role in the disease process. Amyocarditic variant ts5R induced a heart tissue antigen(s), extractable by hypertonic KC1, which inhibited migration of peritoneal exudate cells from CVB3-inoculated myocarditic mice in an agarose droplet cell-migration-inhibition assay. The ts5R variant was amyocarditic at inoculum doses of 10(3) to 10(8) plaque-forming units per mouse, but in cyclophosphamide-immunosuppressed mice, ts5R induced myocarditis. Viable ts5R served as a vaccine and protected mice against CVB3m-induced myocarditis. Murine neonatal skin fibroblasts (MNSF) infected with either virus served as in vitro targets and were lysed by splenic cytotoxic T lymphocytes from mice inoculated with either virus variant. ts5R and CVB3m replicated to similar titers in murine neonatal skin fibroblasts (MNSF) at 24 hr postinoculation (pi), but differences in titers were found by 72 hr pi. Levels of natural killer cell activities in spleens of ts5R-inoculated mice were slightly lower than in spleens of CVB3m-inoculated mice at 7 days pi. The data suggest that viral induction of new antigens on target cells and viral induction of specific cytotoxic T lymphocytes that recognize these antigenic changes do not always result in induction of myocarditis.

Animals↗
PubMed1985

Ameliorating effect of IFN-beta and anti-IFN-beta on coxsackievirus B3-induced myocarditis in mice.

A significant reduction in the number of virus-induced myocardial lesions was effected by administration of murine interferon beta (IFN-beta) or polyriboinosinic: polyribocytidylic acid copolymer (pI:pC) at -24, 0, or 24 h but not 72 h postinoculation (p.i.) of coxsackie-virus B3 (CVB3) to adolescent CD-1 mice. Inoculation of interferon at any of the four times did not reduce virus titers in heart tissues at three or seven days p.i., but inoculation of pI:pC at -24, 0, or 24 h p.i. significantly reduced virus titers. Administration of anti-murine IFN-beta at 72 h p.i. significantly reduced myocarditic lesion numbers. The results suggest that there are two identifiable times after CVB3 inoculation in which interferon may play a role in CVB3-induced myocarditis: a very early time (+/- 24 h of virus entry) in which the presence of interferon is beneficial to the animal and a later time (72 h p.i. of virus) in which absence of interferon is beneficial to the animal. In vitro studies on the effects of IFN-beta or anti-IFN-beta antiserum on replication of CVB3 in permissive primary cultures of murine neonatal skin fibroblasts show that this virus is sensitive to the antiviral action of interferon which is produced in infected cultures.

Animals↗
PubMed1985

Antimyocarditic activity of the guanine derivative BIOLF-70 in a coxsackievirus B3 murine model.

Prophylactic administration of a nontoxic dose of 9-[[2-benzyloxyl-1-(benzyloxymethyl)ethoxy]methyl]-6-chlo roguanine (BIOLF-70) to mice reduced the number of myocarditic lesions induced by coxsackievirus B3 (CVB3). BIOLF-70 exhibited minimal antiviral activity against CVB3 in HeLa cells and murine neonatal skin fibroblasts and minimally reduced CVB3 yields in heart tissues. The drug had no effect on serum anti-CVB3 neutralizing antibody titers and did not induce the production of interferon. Flow microfluorometric analyses of splenic lymphocytes taken from BIOLF-70-treated, CVB3-inoculated mice at 7 days postinoculation showed that the proportion of T lymphocytes was increased, as measured by fluorescent staining of Thy-1 and Lyt-2 surface markers, compared with the proportion of T lymphocytes in splenic cells from virus-inoculated or BIOLF-70-treated or normal groups of mice. Splenic lymphocytes from BIOLF-70-treated, CVB3-inoculated mice showed reduced cytotoxic activity against CVB3-infected target fibroblasts. Splenic cells from BIOLF-70-treated, CVB3-inoculated mice had slightly higher natural killer cell activity than did those from the other three groups of mice, which had comparatively similar levels of natural killer cell activity. The data suggest that BIOLF-70 exerts antimyocarditic activity perhaps by some antiviral activity in heart tissues and by immunomodulatory mechanisms which appear to involve T suppressor or T cytotoxic lymphocyte subpopulations and natural killer cells.

Animals↗
PubMed1985

Coxsackievirus group B antibodies in the ventricular fluid of infants with severe anatomic defects in the central nervous system.

Ventricular fluids from four of 28 newborn infants who were initially seen with severe congenital anatomic defects in the central nervous system contained neutralizing antibody to at least one serotype of coxsackieviruses group B. Two of the four infants with anti-coxsackieviruses group B antibody in the ventricular fluid did not have a detectable level of the same antibody(ies) in their serum. The ventricular fluid of one of the infants had immunoglobulin M neutralizing antibody directed against coxsackievirus B6. Of 11 mother-infant pairs that had neutralizing antibody to coxsackieviruses group B in both sera, nearly half had antibodies directed against more than one serotype. These data suggest the possibility of an association between congenital infections with coxsackieviruses group B and rare severe CNS defects.

Antibodies, Viral↗