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J V Osterman

Publications and source records attributed to J V Osterman.

At least 19 recordsLinked to original sources
PubMed1985

Identification of strain-specific and group-reactive antigenic determinants on the Karp, Gilliam and Kato strains of Rickettsia tsutsugamushi.

Hybridoma antibodies (Hab) were prepared against the Karp, Gilliam and Kato strains of Rickettsia tsutsugamushi and were examined for homologous and heterologous reactivity using an indirect immunofluorescence assay. Strain-specific Hab demonstrated homologous IFA titers ranging from 1/320 to 1/1,280 and did not react (less than 1/10) with the heterologous strains. The cross-reactive Hab generally reacted equally with all three strains in the scrub typhus group; however, there were some Hab that reacted with only one of the two heterologous strains tested. The Hab also were examined in enzyme-linked immunosorbent assays with scrub typhus antigens eluted from SDS-polyacrylamide gels. Most Hab reacted with either one or several of the six eluted antigens detected with a polyclonal immune serum. It was also observed that strain-specific and cross-reactive Hab sometimes reacted with the same antigen, suggesting the existence of multiple antigenic determinants in one electrophoretic peak. The data suggest that strain-specific Hab can be used in the indirect immunofluorescence assay to identify isolates of R. tsutsugamushi without the cross-reactions usually observed with polyclonal antisera, and that they are useful probes for detection and analysis of rickettsial antigens.

Antibodies, Bacterial↗
PubMed1985

Rickettsiae and hosts.

Protective immunity to Rickettsia tsutsugamushi in a murine model is dependent upon the development of cell mediated immunity, as demonstrated by lymphocyte transfer, production of lymphokines and -interferon by thymus-derived lymphocytes, activation of macrophages by lymphokines and demonstration of delayed-type hypersensitivity response following exposure to these organisms. Infection of mice with small numbers of Rickettsia typhi inoculated by a peripheral route leads to a more complex pattern of immune development, with a distinction between resistance to local and systemic infection. Nevertheless, thymus-derived lymphocytes and activated macrophages play a major role in modulating pathogenesis of infection, and delayed-type hypersensitivity responses are evident. Spotted fever group rickettsiae also elicit a cell-mediated response in rodents, and protection against Rickettsia conorii infection has been achieved by adoptive transfer of thymus-derived lymphocytes from immune animals. Limited studies with Rickettsia akari suggest that activation of mouse macrophages is critical to host survival following infection with this organism.

Animals↗
PubMed1984

Susceptibility of inbred mice to rickettsiae of the spotted fever group.

A mouse strain susceptible to lethal infection with Rickettsia conorii was required for testing vaccine efficacy and for studying the immunology and pathogenesis of infection. Among 20 strains of inbred mice inoculated intraperitoneally with the Malish strain of R. conorii, the C3H/HeJ mouse strain was the most susceptible, with a 50% lethal dose of approximately 10 PFU. Infection of all mouse strains resulted in a measurable antibody response; the highest titers correlated with the greatest degree of rickettsial replication as measured by plaque assay of infected spleen homogenates. Inoculation of C3H/HeJ mice with 5.0 log10 organisms of strain Malish by the subcutaneous route did not result in lethal infection. The Casablanca and Moroccan strains of R. conorii were not lethal for C3H/HeJ mice and, in addition, produced plaques in L-929 cells morphologically distinct from those produced by the Malish strain. The only other spotted fever group rickettsia tested which produced a lethal infection in C3H/HeJ mice was Rickettsia sibirica. Sublethal infection with any of the spotted fever rickettsiae tested protected against lethal infection with R. conorii. These data established a lethal challenge system for examining the protective efficacy of spotted fever immunogens and presented evidence of biological variation among strains of R. conorii.

Animals↗
PubMed1983

Gamma-irradiated scrub typhus immunogens: development of cell-mediated immunity after vaccination of inbred mice.

Mice immunized with three injections of gamma-irradiated Karp strain of Rickettsia tsutsugamushi were evaluated for the presence of cell-mediated immunity by using delayed-type hypersensitivity, antigen-induced lymphocyte proliferation, and antigen-induced lymphokine production. These animals also were evaluated for levels of circulating antibody after immunization as well as for the presence of rickettsemia after intraperitoneal challenge with viable Karp rickettsiae. After immunization with irradiated Karp rickettsiae, a demonstrable cell-mediated immunity was present as evidenced by delayed-type hypersensitivity responsiveness, lymphocyte proliferation, and production of migration inhibition factor and interferon by immune spleen lymphocytes. Also, a reduction in circulating rickettsiae was seen in mice immunized with irradiated rickettsiae after challenge with 1,000 50% mouse lethal doses of viable, homologous rickettsiae. All responses except antibody titer and reduction of rickettsemia were similar to the responses noted in mice immunized with viable organisms. Antibody levels were lower in mice immunized with irradiated rickettsiae than in mice immunized with viable rickettsiae. Furthermore, mice that were immunized with viable rickettsiae demonstrated markedly lower levels of rickettsemia after intraperitoneal challenge compared with either mice immunized with irradiated rickettsiae or nonimmunized mice.

Animals↗
PubMed1983

Development of specific and cross-reactive lymphocyte proliferative responses during chronic immunizing infections with Rickettsia tsutsugamushi.

The development of antigen-responsive lymphocytes was followed in mice immunized with the Gilliam, Karp, or Kato strains of Rickettsia tsutsugamushi by utilizing an in vitro lymphocyte proliferation assay. Subcutaneous immunization with viable rickettsiae of all three strains resulted in the appearance of lymphocytes in the spleen responding to irradiated tissue culture-grown rickettsiae used as stimulating antigens. Although all animals demonstrated antigen-induced proliferation elicited by homologous antigen by 14 days after immunization, the time of peak responsiveness varied, depending on the strain of rickettsiae used for immunization. In all cases, peak proliferative responses occurred at a time after immunization that was after the previously reported time after immunization at which resistance to rechallenge was observed. Reactivity to heterologous strains of R tsutsugamushi developed roughly in parallel with homologous reactivity in Karp- and Gilliam-immunized mice, with a marked degree of heterologous reactivity evident. Kato-immunized mice demonstrated greater reactivity to heterologous antigens early in the development of antigen reactivity and demonstrated a somewhat greater degree of cross-reactivity, relative to homologous responses, than the other groups. It was found that nylon wool-nonadherent immune cells, if cultured with antigen and adherent cells obtained from normal spleens or peritoneal exudates, responded in culture. The thymus-derived lymphocyte nature of the responding cell was further suggested when treatment of immune spleen cells with anti-Thy 1.2 serum and complement eliminated antigen response.

Animals↗
PubMed1982

Host defenses in experimental scrub typhus: delayed-type hypersensitivity responses of inbred mice.

Delayed-type hypersensitivity responses of inbred mice during the course of lethal and chronic infections with strains of Rickettsia tsutsugamushi were evaluated by using the influx of radiolabeled cells into antigen-injected ears. Congenic strains of C3H mice, which previously have been shown to be resistant (C3H/RV) or sensitive (C3H/HeDub) to lethal intraperitoneal infection with the Gilliam strain of rickettsiae, both expressed delayed-type hypersensitivity early in the course of infection (5 to 7 days). The sensitive C3H/HeDub mice, however, exhibited a marked decline in reactivity just before death. In contrast, reactivity of C3H/RV mice remained high through day 9 and declined slowly through day 15 after infection. Similar results were obtained when BALB/c mice were infected with either the Karp or the Gilliam strain of rickettsiae, which produce a lethal or nonlethal infection, respectively, in this strain of mice. Rechallenge of C3H/RV mice elicited a rapid increase in reactivity, suggesting a secondary memory response. To analyze delayed-type hypersensitivity during chronic infection, C3H/HeDub mice were immunized by subcutaneous infection with the Gilliam strain of R. tsutsugamushi, and both delayed-type hypersensitivity reactivity and resistance to intraperitoneal challenge were examined. Delayed-type hypersensitivity reactivity developed slowly and peaked at 21 days postimmunization, which correlated with resistance to intraperitoneal challenge. Delayed-type hypersensitivity reactivity declined thereafter, but resistance to intraperitoneal challenge remained through 28 days postimmunization. Delayed-type hypersensitivity reactivity increased after secondary challenge at 28 days, again suggesting antigen memory generated by primary immunization. Transfer of delayed-type hypersensitivity reactivity was accomplished by using immune thymus-derived splenic lymphocytes isolated with nylon-wool columns. Abrogation of the ability of immune spleen cells to transfer delayed-type hypersensitivity reactivity after treatment with anti-Thy 1.2 alloantiserum and complement further supported the view that delayed-type hypersensitivity responses to scrub typhus rickettsiae were mediated by thymus-derived lymphocytes.

Animals↗
PubMed1982

Role of macrophages in innate and acquired host resistance to experimental scrub typhus infection of inbred mice.

Mechanisms of innate resistance to infection with the Gilliam strain of Rickettsia tsutsugamushi were examined using congenic strains of mice resistant (C3H/RV) or susceptible (C3H/He) to intraperitoneal infection. Both strains of mice were resistant to infection with 1,000 50% mouse lethal doses of rickettsiae if given intravenously. In both systems rickettsial replication occurred after intravenous infection, as evidenced by an increase in rickettsial numbers in the spleens of infected animals, followed by a decrease in rickettsiae to low levels by day 14 postinfection. Administration of the antimacrophage agents silica and carrageenan to C3H/He mice intravenously rendered these animals susceptible to lethal infection. Neither irradiation nor silica given individually rendered C3H/RV mice susceptible to intravenous infection. However, if silica and irradiation were given together, a lethal infection occurred after intravenous infection. C3H/RV mice became susceptible to lethal infection after sublethal doses of irradiation only if they were infected intraperitoneally. Administration of silica or carrageenan had no effect on the outcome of intraperitoneal infection of these mice with Gilliam rickettsiae. These data suggest that both strains of mice share innate resistance mechanisms to intravenous infection that consist of fixed macrophages. Resistance of C3H/RV mice to intraperitoneal infection, in contrast, apparently was dependent only on an irradiation-sensitive process.

Animals↗
PubMed1982

Rocky Mountain spotted fever in areas of high and low prevalence: survey for canine antibodies to spotted fever rickettsiae.

Antibodies to Rickettsia rickettsii were detected by indirect immunofluorescence in sera from 149 of 467 dogs (32%) examined from 4 military installations located in Kentucky, North Carolina, Pennsylvania, and Virginia. The prevalence at individual installations ranged from 4.3% at Fort Knox, Ky, to 63.4% at Fort Bragg, NC. Most of the seropositive dogs were in the working and sporting groups of dogs. The difference in antibody prevalence between sexes was not significant. Serologic responses were related to R rickettsii infection, although antibodies to R montana also were detected in a few of the sera. Comparison of serodiagnostic methods indicated that the indirect fluorescent antibody test was more sensitive than was the indirect hemagglutination test for obtaining survey data on the prevalence of Rocky Mountain spotted fever in the area.

Animals↗
PubMed1981

Host defenses in experimental scrub typhus: inflammatory response of congenic C3H mice differing at the Ric gene.

Two strains of C3H mice differed in their susceptibility to lethal infection with Rickettsia tsutsugamushi strain Gilliam. Adult C3H/RV mice were markedly more resistant to lethal infection than C3H/HeDub mice, and both were histocompatible as assessed by mixed-lymphocyte cultures and graft-versus-host responses. The inflammatory response of susceptible C3H/HeDub mice to intraperitoneal infection was evident approximately 5 days postinfection, and the magnitude of the cellular influx increased until death of the animal. The inflammation consisted of an early polymorphonuclear leukocyte response, followed by a mononuclear cell influx which persisted until death of the animal. The C3H/RV mice evidenced similar kinetics of cell influx, but the inflammatory response was significantly reduced in magnitude, and the response of C3H/RV animals to Gilliam was predominantly mononuclear in nature, with little influx of polymorphonuclear leukocytes into the peritoneal cavity. C3H/RV mice were rendered susceptible to Gilliam infection by induction of a nonspecific inflammation with thioglycolate if given 3 days after infection. Conversely, treatment of C3H/HeDub mice with indomethacin, an anti-inflammatory agent, prolonged survival after infection with Gilliam. The results of this study indicate that genetic resistance to Gilliam is not due simply to a greater host response to infection or, conversely, that susceptibility is due to a host response quantitatively lacking in a cellular component necessary for antirickettsial immunity.

Animals↗
PubMed1981

Antigens of scrub typhus rickettsiae: separation by polyacrylamide gel electrophoresis and identification by enzyme-linked immunosorbent assay.

Antigens of plaque-purified Rickettsia tsutsugamushi strains Gilliam, Karp, and Kato were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and were analyzed by an enzyme-linked immunosorbent assay. Six antigens were identified in each of the three prototype strains; in strain Gilliam, these antigens were located in the cell envelope fraction of the organisms. Reactivity of these isolated antigens with homologous or heterologous immune sera indicated that different macromolecules existed in all three strains, although they exhibited very similar mobilities during electrophoresis. Antigens of strain Gilliam reacted equally well with antibodies directed against Gilliam, Karp, or Kato rickettsiae. However, strains Karp and Kato each had two distinct antigens which did not react with heterologous antisera. R. tsutsugamushi antigens retained immunogenicity after electrophoresis, and antisera raised against them reacted with intact organisms and exhibited specificity in reactions with isolated antigens.

Antibodies, Bacterial↗
PubMed1980

Host defenses in experimental rickettsialpox: genetics of natural resistance to infection.

The genetic basis for natural resistance to lethal infection with Rickettsia akari was studied in over 25 inbred strains, inbred hybrids, and outbred stocks of mice. Inbred mice infected intraperitoneally with the Kaplan strain of R. akari demonstrated three levels of response, susceptible (C3H/HeJ), intermediate (A/HeJ, A/J, A/WySn, BALB/cDub, BALB/cJ, and SJL/J), and resistant (AKR/J, AL/N, BALB/cAnN, BALB/cNCr1BR, C3H/HeN, C57BL/6J, C57L/J, CBA/J, DBA/2J, and SWR/J). No correlation was evident between the six H-2 haplo-types tested and susceptibility to Kaplan infection. Four outbred mouse stocks, Dub: (ICR), Wrc:(ICR), Caw:(CF1), and Mai:(S) were all resistant. The F1 inbred hybrids of resistant X resistant (AKD2F1/J), resistant X intermediate (CB6F1/U), intermediate X intermediate (CAF1/J), and resistant X susceptible (C3D2F1/J) parents were all resistant. The F2 and parental backcross generations of C3H/HeJ and DBA/2J hybrids yielded ratios of resistant to susceptible mice that suggested resistance was under multigeneic control. Susceptible mice (C3H/HeJ) were capable of mounting an immune response, since prior infection with the avirulent Hartford strain of R. akari rendered them resistant to subsequent lethal challenge with the Kaplan strains.

Animals↗
PubMed1980

Gamma-irradiated scrub typhus immunogens: analysis for residual, replicating rickettsiae.

Scrub typhus immunogens that received inadequate gamma radiation contained residual, viable rickettsiae. The presence of these organisms in the host was masked by the rapid immune response elicited by the large number of inactivated rickettsiae. Transfer of homogenized spleen cells from immunized mice to normal syngeneic recipients provided a sensitive technique for the detection of these viable, replicating organisms.

Animals↗
PubMed1980

Host defenses in experimental rickettsialpox: resistance of C3H mouse sublines.

Eight sublines of C3H mice were tested for their resistance to lethal infection with Rickettsia akari,. strain Kaplan. C3H/HeJ mice were unique in their susceptibility to approximately one plaque-forming unit of rickettsiae. This lack of resistance is apparently due to a mutation in the mouse strain which occurred after 1950.

Animals↗
PubMed1980

Somatic cell hybrids of canine peritoneal macrophages and SV40-transformed human cells: derivation, characterization, and infection with Ehrlichia canis.

Somatic cell hybrids were obtained by fusion of canine peritoneal macrophages and SV40-transformed human skin fibroblasts. A cell line (WRH-2) was established from a single isolated hybrid clone. The WRH-2 cell line has been serially passaged 60 times and has a population doubling time of approximately 24 hours. Karyotypic analysis showed the modal number of chromosomes to be 80, with a selective segregation of canine chromosomes. Expression of incorporated canine DNA was substantiated by cellular enzyme activities and antigen expression. The susceptibility of 5% to 7% of WRH-2 cells to Ehrlichia canis infection was associated with phagocytic properties of these cells. Magnetic separation of phagocytic cells after ingestion of carbonyl iron resulted in a significant enhancement of the phagocytic population with a concomitant increase in the percentage of cells susceptible to ehrlichial infection. Serial passage of the selected subpopulation of hybird cells, however, resulted in a rapid diminution in the percentage of phagocytic cells.

Animals↗
PubMed1980

Host defenses in experimental scrub typhus: mapping the gene that controls natural resistance in mice.

Natural resistance of mice to lethal ifections of Rickettsia tsutsugamushi, strain Gilliam, is controlled by a single, autosomal, dominant gene, which we have designated Ric, with r and s representing the resistant nd susceptible alleles, respectively. Using three sets of recombinant inbred mouse strains (BXD, BXH, and BXJ), the Ric locus was mapped to Chromosome 5 closely linked to the retinal degeneration (rd) locus. This linkage was confirmed by a backcross analysis. Based on the RI strains and the C57BL/6Ty-le congenic strain (the only proven Ric-rd cross-over), we estimate the recombination frequency between Ric and rd to be 0.015. Three presumptive Ric-rd recombinants detected among 93 backcross mice may represent caes of incomplete penetrance of the resistance allele rather than recombination. Analyis of th C57BL/6JTy-le congenic strain indicates that Ric is proximal to rd on Chromosome 5. If so, the correct gene order is Pgm-1-W-Ric-rd-Gus.

Animals↗