Biomedical subjects

S W Barthold

Publications and source records attributed to S W Barthold.

At least 109 records · Page 6Linked to original sources

PubMed1993

Long-term study of cell-mediated responses to Borrelia burgdorferi in the laboratory mouse.

Borrelia burgdorferi infection of disease-susceptible (C3H) and -resistant (BALB) mice resulted in impaired proliferation to both T- and B-cell mitogens up to 30 days after inoculation. Interleukin-2 and -4 production was also impaired, paralleling the T-cell response to concanavalin A. Impaired lymphocyte proliferation could not be attributed to diminished numbers of T or B cells and was found to depend on the lymphoid organ (spleen or lymph node) examined. Prostaglandin production accounted for part of this immune dysfunction. Attempts to assess antigen-specific proliferation to B. burgdorferi were inconsistent, and delayed-type hypersensitivity responses were not detected. Adoptive transfer of T-enriched cells from chronically infected donors failed to prevent infection and disease development in recipient C3H mice. The current study emphasizes caution in the study of B. burgdorferi antigen-specific assays and argues against the role of a vigorous T-cell response in Lyme borreliosis in infected laboratory mice.

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PubMed1993

OspA vaccination of mice with established Borrelia burgdorferi infection alters disease but not infection.

C3H mice were actively immunized with outer surface protein A (OspA) at different intervals after infection with Borrelia burgdorferi to determine the effect of postexposure vaccination on the course of murine Lyme borreliosis. Mice were vaccinated with an OspA-glutathione transferase fusion protein or glutathione transferase (control) in complete Freund's adjuvant; vaccination was followed by two weekly booster injections in incomplete adjuvant. Two weeks after the final booster injection, organs were cultured for B. burgdorferi (blood, spleen, skin, and bladder) and examined for histopathology (joints and hearts). When vaccination was commenced in the early stages (5 to 14 days) of infection, active immunization with OspA partially cleared spirochetes from the bloodstream but did not eliminate them from other tissues or alter the course of joint or heart disease. Commencement of vaccination at 60 days after infection (at which time joint or heart disease is resolving), however, reduced both the number of mice and individual joints with arthritis, a result suggesting an acceleration of the resolution phase of the disease. Postexposure immunization with OspA may partially alter the course of murine Lyme arthritis but does not eliminate infection.

Animals↗

PubMed1993

Enterotropic coronavirus (mouse hepatitis virus) in mice: influence of host age and strain on infection and disease.

The course of enterotropic mouse hepatitis virus (MHV) infection was examined in genetically susceptible (BALB) and resistant (SJL) mice of different ages at inoculation (1, 3, and 12 weeks) and at sequential intervals (1, 2, 3, 5, 10, 20, and 30 days) after oral inoculation with the Y strain of MHV (MHV-Y). Virus was quantified in stomach, upper and lower segments of small intestine, cecum, upper and lower segments of colon, Peyer's patches, mesenteric lymph node, and feces, and tissues were examined microscopically. An infant mouse bioassay was used to quantify virus in all tissues of 3-week-old BALB mice and ascending colons of other mouse groups. MHV-specific serum IgG antibody titers were measured with an enzyme immunoassay, using MHV-S-infected 17 Cl 1 cells as antigen. Lesions were first detectable at 2 days and were most severe in 1-week-old mice and more severe in BALB mice, compared with SJL mice of the same age. Additional BALB mice inoculated at the age of 24 hours developed severe necrotizing enterocolitis, whereas SJL mice inoculated at the age of 24 hours developed lesions equivalent to those in 1-week-old BALB mice. Virus was first detectable at 2 days and virus titers were highest at 2, 3, and 5 days, then diminished on days 10, 20, and 30. Low titers of virus were found in a few mice of different ages and genotypes through day 30. Lesions were most severe and virus titers highest in the ascending colon.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗

PubMed1993

Infectivity, disease patterns, and serologic profiles of reovirus serotypes 1, 2, and 3 in infant and weanling mice.

The oronasal median infectious doses of reovirus serotypes 1, 2, and 3 were established in infant and weanling Sencar mice on the basis of disease expression and seroconversion. Infant mice were susceptible to infection with low doses of all three serotypes, whereas weanling mice were comparatively resistant to infection. Uniform transmission of virus to cagemates or mothers of infants did not occur, indicating low contagiousness of all three virus serotypes. The comparative susceptibility of 2-day-old Sencar mice to disease was examined following oronasal inoculation with reovirus 1, 2, or 3. Tissues were collected on days 3, 5, 7, 9, 14, 16, and 21 after inoculation for virus isolation, histologic examination, and serologic analysis. Disease patterns in infant mice were distinctly different among reovirus serotypes. Reovirus 3 induced severe disease, with focal myocarditis, hepatitis, diffuse encephalitis, and generalized lymphoid depletion, whereas reovirus 1 induced a similar pattern, but much milder disease. In contrast, reovirus 2 induced mild transient enteritis without lesions in other organs. Sera from experimentally infected mice were tested in virus serotype-specific enzyme immunoassays. Cross reactivity of antibody among the three virus serotypes was found, but antibody titers were always highest with the homologous antigen. These studies confirm that infant laboratory mice are susceptible to infection with all three serotypes of virus; weanling mice are comparatively resistant to infection and disease; the viruses induce different patterns of disease in infant mice; and infecting virus serotypes can be distinguished serologically by enzyme immunoassay.

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PubMed1993

Chronic Lyme borreliosis in the laboratory mouse.

C3H/HeJ mice were inoculated intraperitoneally with 10(7) uncloned Borrelia burgdorferi at 4 weeks of age and examined on days 30, 90, 180, and 360. Spirochetes were isolated from multiple tissues at all intervals. Joint and heart disease were present in all mice at 30 days and resolved after 90 days. At 180 and 360 days, some mice had mild recurrent joint and heart disease, and most had peripheral segmental periarteritis. The protein electrophoretic migration of 360-day isolates differed from the original inoculum. The experiment was repeated with C3H/HeN and BALB/cByJ mice inoculated intradermally with 10(4) cloned B. burgdorferi. Characterization of infection and disease at 180 and 360 days were similar to those of the first experiment, but spirochetal proteins of isolates from both intervals displayed no protein variation in electrophoretic mobilities. Spirochetes isolated at 360 days were fully pathogenic in naive mice. Sera from infected mice showed an initial immunoglobulin M response, followed by a sustained immunoglobulin G response, involving IgG1, IgG2a, IgG2b and IgG3, with expanding reactivity against multiple antigens over time. These results indicate that immunocompetent mice sustain persistent infections and develop early acute joint and heart lesions that resolve and then recur intermittently.

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PubMed1993

The cellular and molecular pathogenesis of coronaviruses.

Coronaviruses cause a wide spectrum of diseases in humans and animals but generally fall into two classes, with respiratory or enteric tropisms. Mouse hepatitis virus (MHV) and rat coronaviruses are the viruses most frequently encountered in the laboratory animal setting. This review focuses primarily on the cellular and molecular aspects of MHV pathogenesis. The high mutation and recombination rates of coronaviruses lead to a diverse, ever-changing population of MHV strains. The spike (S) protein is the most variable coronavirus protein and is responsible for binding to cell surface receptors, inducing cell fusion and humoral and cellular immunity. Differences within the S protein of different MHV strains have been linked to their variable tropisms. Since immunity to MHV is strain-specific, seropositive mice can be reinfected with different strains of MHV. Natural infections with MHV are acute, with persistence occurring at the population level, not within an individual mouse, unless it is immunocompromised. Age, genotype, immunologic status of the mouse, and MHV strain influence the type and severity of disease caused by MHV. Interference with research by MHV has been reported primarily in the fields of immunology and tumor biology and may be a reflection of MHV's capacity to grow in several types of immune cells. While many methods are available to diagnose coronavirus infection, serologic tests, primarily ELISA and IFA, are the most commonly used. MHV is best managed on a preventive basis. Elimination of MHV from a population requires cessation of breeding and halting the introduction of naive mice into the population.

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PubMed1992

Elimination of Borrelia burgdorferi from vector ticks feeding on OspA-immunized mice.

Although recombinant outer surface protein A (OspA) of Borrelia burgdorferi protects mice against injected Lyme disease spirochetes, the mode of protection has not yet been explored. Indeed, the efficacy of vaccine-induced immunity against a realistic vector-mediated challenge remains unexplored. Accordingly, we determined whether this immunogen protects mice against spirochetes delivered by nymphal Ixodes dammini ticks. Following challenge by tick bite, no spirochetes could be cultured from immunized mice, and no characteristic histopathology was found. The spirochete was not detected in ticks that fed on immunized animals and was present in virtually all ticks that fed on nonimmunized mice. We conclude that OspA-immunized mice are protected from spirochetal infection, at least in part, because the spirochete is destroyed in the infecting tick.

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PubMed1992

Borrelia burgdorferi strain 25015: characterization of outer surface protein A and vaccination against infection.

Mice vaccinated with outer surface protein A (OspA) from Borrelia burgdorferi strain N40 are protected from challenge with an intradermal syringe inoculum of B. burgdorferi strains N40, B31, and CD16. Vaccination experiments were done to determine if protection extended to strains 297 and 25015. We now show that OspA-N40 immunized mice are protected against challenge with strain 297, isolated from the cerebrospinal fluid of a patient with neuroborreliosis, but not against challenge with strain 25015, isolated from a tick in Millbrook, NY. The OspA gene from strain 25015 was therefore cloned and sequenced. The deduced OspA-25015 protein sequence differs from OspA-N40 at 40 of 273 amino acids. Furthermore, mice vaccinated with rOspA-25015 are protected from challenge with strain 25015 but not against strain N40. The results extend the usefulness of OspA as a vaccine candidate, but indicate that OspA can vary among strains of B. burgdorferi and that vaccination of mice with OspA-N40 does not protect against intradermal challenge with an inoculum of 10(4) strain 25015 spirochetes.

Amino Acid Sequence↗

PubMed1992

Responses of mice to murine coronavirus immunization.

Oral and/or intranasal inoculation of susceptible mouse genotypes with the JHM strain of mouse hepatitis virus (MHV-JHM) consistently results in T cell dysfunction as reflected by in vitro proliferative responses to mitogens or allogeneic cells. One approach to examining the mechanism responsible for the observed functional T cell suppression is to determine whether virus replication is required for its induction. To this end, mice were inoculated oronasally with MHV-JHM that was inactivated with short-wave ultraviolet light, beta-propiolactone or psoralen. Mice were also inoculated with live MHV-JHM after recovery from homotypic or heterotypic MHV infection. Spleen cells from BALB mice inoculated oronasally with inactivated MHV-JHM yielded extremely variable in vitro proliferative responses after concanavalin A stimulation. MHV-susceptible mice exposed oronasally or intraperitoneally to virus inactivated by any of the minimum effective treatments failed to seroconvert. Immunization with psoralen-treated virus intraperitoneally in Freund's complete adjuvant or oronasally failed to protect from live virus challenge, but survivors had elevated virus-specific serum IgG antibody titers compared to mock-immunized controls at two weeks post-challenge. Spleen cells from mice that were challenged after recovery from homotypic live virus infection did not exhibit the profound in vitro T cell suppression normally observed during the acute stage of primary infection. In contrast, MHV-JHM challenge of mice vaccinated with heterotypic live MHV-S resulted in significantly depressed in vitro T cell function. The combined data suggest that either virus replication or exposure to more concentrated antigen may be required for induction of the dramatic T cell dysfunction that occurs as a consequence of MHV-JHM infection as well as for a detectable MHV-specific humoral response.

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PubMed1992

Passively acquired challenge immunity to enterotropic coronavirus in mice.

Maternally-derived passive immunity of infant mice to challenge infection with enterotropic coronavirus mouse hepatitis virus strain Y (MHV-Y) was studied. Pups born to both naive and immune dams, but nursed by naive foster dams, were susceptible to infection, while naive or immune pups nursed by immune foster dams were protected. The MHV infectious dose was identical among naive pups inoculated at 1, 2, 3, or 4 weeks of age. Pups nursing immune dams resisted infection when inoculated at 1, 2, or 3 weeks of age. Three week old pups were protected only if they were allowed access to their immune dams. Pups born to MHV immune dams 4 in consecutive litters acquired equal MHV IgG titers in serum and whey and were all protected against challenge infection. Only pups actively ingesting immune whey at the time of or within two hours after virus inoculation were effectively protected. Pups born to dams immunized by oral inoculation with live MHV acquired both MHV-specific IgA and IgG in their whey, while pups born to dams immunized with killed virus acquired only IgG. Both IgA and IgG, but not IgG alone, were required for complete protection.

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PubMed1992

Viremic dissemination of mouse hepatitis virus-JHM following intranasal inoculation of mice.

Using a sensitive infant mouse bioassay to detect infectious virus, the pattern of mouse hepatitis virus (MHV) JHM dissemination in blood and other tissues was examined during the first 5 days following intranasal inoculation. MHV replicated in nasal turbinates of both susceptible BALB and resistant SJL mice from days 1 through 5, but BALB mice had higher titers on days 1 and 2. Viremia was detectable on days 1 through 5 in BALB mice, but only on days 3 and 5 in SJL mice. Transient virus replication occurred in the lungs of both mouse genotypes at 1 and 2 days, then ceased. This correlated with more consistently demonstrable virus in blood collected from the left atrium of the heart, compared to jugular vein, portal vein and right atrial blood. Virus was associated equally with the plasma and cellular fractions of blood on day 3, but was primarily in the buffy coat of the cellular fraction on day 5. Interferon-alpha/beta was detected in serum and spleen, but not liver or brain of BALB mice or in any tissue of SJL mice. BALB serum and spleen interferon was first detected at 36 h, peaked between 48 and 72 h, and was undetectable by 108 h. The distribution of virus in nose, cervical, axillary and mesenteric lymph nodes, spleen, Peyer's patch, thymus, bone marrow and liver was examined at 1, 2, and 3 days. The resulting pattern suggested lymphatic spread of virus to cervical lymph node and mesenteric lymph node as pathways of dissemination in addition to viremia.

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PubMed1992

Nonspecific proliferative responses of murine lymphocytes to Borrelia burgdorferi antigens.

Proliferative responses of naive splenocytes to Borrelia burgdorferi antigens from mice susceptible (C3H) and resistant (BALB) to Lyme borreliosis were investigated. B. burgdorferi spirochetes and recombinant outer surface proteins, OspA and OspB, were found to induce nonspecific proliferation of naive splenocytes from both strains of mice. Cell purification studies localized nonspecific proliferation to the B cell-enriched fraction. B. burgdorferi, OspA, and OspB were found to induce IgM and IgG synthesis in vitro. The mitogenic effect of B. burgdorferi was dissimilar to that of lipopolysaccharide (LPS), in that B cells from C3H/HeJ mice (LPS-unresponsive) responded at levels comparable to those from C3H/HeNCrlBr mice. These results emphasize the need for caution in the study of antigen-specific proliferation for B. burgdorferi.

Animals↗

PubMed1992

Roles of OspA, OspB, and flagellin in protective immunity to Lyme borreliosis in laboratory mice.

Vaccination with recombinant outer surface protein A (OspA) has been shown to protect mice from infection with Borrelia burgdorferi, the Lyme disease agent. To determine whether antibodies to B. burgdorferi proteins other than OspA are involved in protective immunity, antibodies to OspA were removed from protective anti-B. burgdorferi serum; the residual serum was still protective. Absorption of OspA and OspB antibodies from anti-B. burgdorferi serum eliminated the protective effect. Therefore, active immunization experiments were performed to determine the roles of OspB and flagellin in protective immunity and to determine whether protective immunity induced by OspA is dose dependent. Active immunization with recombinant OspA protected mice from infection with an inoculum of 10(4) spirochetes, but this protection could be overcome with a challenge of 10(7) spirochetes; OspB protected mice from infection with an inoculum of 10(3) spirochetes but was insufficient to fully protect against 10(4) organisms; and immunization with flagellin had no protective effect. These studies suggest that OspA and OspB, but not flagellin, play roles in protective immunity to spirochete infection.

Animals↗

PubMed1992

Long-term protection of mice from Lyme disease by vaccination with OspA.

Mice vaccinated with recombinant outer surface protein A (OspA) have been shown to be protected from infection with Borrelia burgdorferi, the agent of Lyme disease, when sacrificed 14 days after challenge with an intradermal inoculum of the spirochete. To determine whether infection was not merely delayed and that protection was long-lasting, we sacrificed vaccinated mice 60, 120, and 180 days after challenge; and to determine whether vaccinated mice retained their immune state over long periods, we challenged mice with B. burgdorferi 60, 90, 120, and 150 days after vaccination. The results of both groups of experiments show that the mice remained free from infection and disease and extend the usefulness of OspA as a vaccine candidate for Lyme borreliosis.

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PubMed1992

The putative E5 open reading frame of cottontail rabbit papillomavirus is dispensable for papilloma formation in domestic rabbits.

In the cottontail rabbit papillomavirus (CRPV)-rabbit system, recombinant CRPV DNA can induce papillomas. This investigation was undertaken to evaluate whether the E5 open reading frame (ORF) of CRPV is required for papilloma formation. The CRPV genome we utilized, CRPV-WA, was sequenced in the E5 region and was found to contain one deletion, two insertions, and one transition mutation compared with CRPV-KS, the CRPV genome that has been fully sequenced. Despite these differences, an intact E5 ORF is preserved, supporting the notion that this gene may serve a biological function. One frameshift and two in-frame mutations were constructed in the small region of the 5' end of the E5 ORF that follows the E2 stop codon and precedes the L2 ORF. Several hundred rabbit skin sites were inoculated with each DNA preparation with a jet injector to test the ability of three CRPV E5 mutant DNAs to induce papillomas. In vivo results showed that each of the mutants induced papillomas, and biochemical analysis demonstrated that the E5 mutations present in DNA inocula were retained in the papillomas. The frequency of papilloma formation, however, was generally lower with each of the CRPV E5 mutants than with wild-type CRPV DNA, particularly so for the E5 frameshift mutant, suggesting that although the recognized E5 ORF is not required in domestic rabbits for the induction of papillomas by CRPV DNA, it may facilitate their formation.

Amino Acid Sequence↗

PubMed1992

Carditis in Lyme disease susceptible and resistant strains of laboratory mice infected with Borrelia burgdorferi.

The clinical and pathologic evolution of cardiac Lyme disease was evaluated in four-week-old susceptible C3H/He (C3H) and resistant C57Bl/6 (B6) mice on days 3, 6, 10, 15, 30, 60, and 90 after intradermal inoculation with Borrelia burgdorferi strain N40. Culture, DNA polymerase chain reaction, in situ nucleic acid hybridization, immunoperoxidase histochemical analysis, and silver stain were used to detect spirochetes. Spirochetes were first detected by culture on day 6 in two of four C3H mice. The hearts of all mice of both genotypes were culture positive by day 10 and infection persisted through day 90. The spirochetes had a predilection for connective tissue in the heart base, especially around the aorta, epicardium of the upper ventricles and atria, myocardial interstitium, and endocardium. Carditis was first detectable on day 10, reaching a maximum severity on day 15, then resolved, except for persistence of periaortic lymphoplasmacytic infiltrates through day 90 in C3H mice and through day 60 in B6 mice. The C3H mice developed more severe disease than the B6 mice, and this was associated with the earlier appearance, greater numbers, and later clearance of spirochetes in C3H mice. Electrocardiographs of infected and control mice revealed bradycardia and tachycardia in many C3H mice, but in very few B6 mice. Serum creatinine phosphokinase levels did not become elevated at any interval.

Animals↗

PubMed1992

Lyme borreliosis in genetically resistant and susceptible mice with severe combined immunodeficiency.

The evolution of Lyme borreliosis was examined in genetically resistant C.B-17 and susceptible C3H/He(C3H) mice homozygous for the severe combined immune deficiency (scid) gene, or their immunocompetent counterparts. The C.B-17, C.B-17-scid, C3H, and C3H-scid mice were inoculated intradermally with 10(4) Borrelia burgdorferi and examined on days 14, 21, 30, 45, and 60 after inoculation. Spirochetemia was detected through 30 days, but was cleared in all groups by 45 days. Kidney and brain were inconsistently culture positive, but spleen and ear punch samples were positive in most mice. Immunocompetent C.B-17 and C3H mice seroconverted with equivalent IgG titers to B. burgdorferi, while C.B-17-scid and C3H-scid mice did not seroconvert. Arthritis occurred in nearly all joints examined in all genotypes on day 14, was of equal severity among C.B-17, C.B-17-scid, and C3H mice, but was more severe in C3H-scid mice. By days 30 and 45, arthritis began to resolve in immunocompetent mice, with C3H mice having more severe disease than C.B-17 mice. Arthritis persisted in C.B-17-scid and C3H-scid mice. Carditis occurred to an equal degree in all groups on day 14, remained active in scid mice, but regressed in immunocompetent mice at later intervals. Many spirochetes were visualized with silver stain in inflamed synovial tissues of scid mice, and were present in other tissues in smaller numbers. These studies show that specific immunity is not involved in arthritogenesis or genetically determined susceptibility to arthritis, but is involved in arthritis and carditis regression.

Animals↗

PubMed1992

Duration and strain-specificity of immunity to enterotropic mouse hepatitis virus.

We examined the duration and strain-specificity of immunity to enterotropic mouse hepatitis virus (MHV). Two strains of enterotropic MHV (MHV-Y and MHV-RI) were determined to be distinct virus strains by serum neutralization and by enzyme immunoassay. BALB/cByJ mice immunized by oral infection with either MHV-Y or MHV-RI developed serum MHV IgG titers that remained stable for more than 6 months. The animals were protected from reinfection with the homologous virus strain at 1 and 6 months after an initial immunizing infection, based on intestinal histology and polymerase chain reaction for a 375-base-pair segment of the membrane glycoprotein gene. Immunity was also fully protective against challenge with the heterologous strain 1 month after initial immunization and partly protective after 6 months. Maternally-derived passive immunity prevented MHV infection in 1-week-old pups challenged with the homologous strain of MHV, and pups challenged with the heterologous virus strain were partially protected.

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