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At least 307 records · Page 17Linked to original sources

Antigenic variation in rabies and rabies-related viruses: cross-protection independent of glycoprotein-mediated virus-neutralizing antibody.

Immunization experiments with vaccines prepared from the PM and ERA strains of rabies virus demonstrated that in mice, only ERA vaccine primes for an anamnestic response to the rabies-related strain Duvenhage (DUV6); in rabbits, both ERA and PM vaccines induced immunologic memory to DUV6 virus. In mice, ERA vaccine, but not an equal concentration of PM vaccine, conferred protection against a lethal challenge infection with DUV6 virus. This result indicated that the protective activity correlated with the vaccine's ability to induce immunologic memory. A vaccine prepared from a sequentially selected, neutralization-resistant, multiple-variant virus conferred protection against challenge with the parental strain, a result indicating that antigenic variation of the glycoprotein may not be the sole factor in determining the relative efficacy of rabies prophylaxis. We found no correlation between titers of neutralizing antibody and mortality rates in mice immunized with purified glycoprotein from these viruses.

Animals↗

Expression and characterization of genetically engineered human immunodeficiency virus-like particles containing modified envelope glycoproteins: implications for development of a cross-protective AIDS vaccine.

Noninfectious human immunodeficiency virus type 1 (HIV-1) viruslike particles containing chimeric envelope glycoproteins were expressed in mammalian cells by using inducible promoters. We engineered four expression vectors in which a synthetic oligomer encoding gp120 residues 306 to 328 (amino acids YNKRKRIHIGP GRAFYTTKNIIG) from the V3 loop of the MN viral isolate was inserted at various positions within the endogenous HIV-1LAI env gene. Expression studies revealed that insertion of the heterologous V3(MN) loop segment at two different locations within the conserved region 2 (C2) of gp120, either 173 or 242 residues away from the N terminus of the mature subunit, resulted in the secretion of fully assembled HIV-like particles containing chimeric LAI/MN envelope glycoproteins. Both V3 loop epitopes were recognized by loop-specific neutralizing antibodies. However, insertion of the V3(MN) loop segment into other regions of gp120 led to the production of envelope-deficient viruslike particles. Immunization with HIV-like particles containing chimeric envelope proteins induced specific antibody responses against both the autologous and heterologous V3 loop epitopes, including cross-neutralizing antibodies against the HIV-1LAI and HIV-1MN isolates. This study, therefore, demonstrates the feasibility of genetically engineering optimized HIV-like particles capable of eliciting cross-neutralizing antibodies.

AIDS Vaccines↗

Cross-protective aspects of glucosyltransferase antigens in the hamster caries model.

1) Glucosyltransferase serotypes a and g are closely related antigenically but are more distantly related to GTF of serotype c, based on assays of inhibition of total glucan synthesis. 2) Local immunization with GTF from serotype c S. mutans reduces the colonization, caries, and lesions caused by infection with the homologous strain compared with sham injected controls. 3) Local immunization with GTF of serotype c S. mutans reduces the colonization, caries, and lesions caused by infection with S. mutans of serotype g (strain 6715).

Animals↗

Gamma-irradiated influenza A virus can prime for a cross-reactive and cross-protective immune response against influenza A viruses.

A-strain influenza virus A/JAP (H2N2) was tested for its ability to induce cytotoxic T cells (Tc) after being rendered non-infectious by either UV or gamma irradiation. Gamma-irradiated virus proved to be more efficient than UV-inactivated virus in priming for a memory Tc cell response or in boosting memory spleen cells in vitro. Most importantly, gamma-inactivated, but not UV-inactivated, A/JAP immunized animals survived lethal challenge with heterologous (A/PC(H3N2), A/WSN(H1N1)) virus as effectively as mice primed with infectious virus.

Animals↗

Immunization with outer surface protein (Osp) A, but not OspC, provides cross-protection of mice challenged with North American isolates of Borrelia burgdorferi.

The identification of antigens with the capacity to induce a broad spectrum of protective immunity is an important consideration in the design of a Lyme disease vaccine. In this study, the range of protection provided by outer surface protein (Osp) A or OspC vaccination was compared. Mice actively immunized with OspA or OspC were challenged with 3 North American isolates of Borrelia burgdorferi. OspA-immunized mice were fully protected from infection with each of the isolates, whereas mice immunized with OspC were protected from infection with the homologous isolate but not with 2 heterologous isolates. Sequence analysis revealed that the ospA genes from these 3 isolates were >99% homologous, whereas the ospC genes shared only 81%-85% homology. Western blot analysis suggested antigenic heterogeneity associated with OspC but not OspA. These results indicate that genetic and antigenic heterogeneity may limit the usefulness of OspC as a vaccine constituent.

Amino Acid Sequence↗

Intrahepatic genetic inoculation of hepatitis C virus RNA confers cross-protective immunity.

Naturally occurring hepatitis C virus (HCV) infection has long been thought to induce a weak immunity which is insufficient to protect an individual from subsequent infections and has cast doubt on the ability to develop effective vaccines. A series of intrahepatic genetic inoculations (IHGI) with type 1a HCV RNA were performed in a chimpanzee to determine whether a form of genetic immunization might stimulate protective immunity. We demonstrate that the chimpanzee not only developed protective immunity to the homologous type 1a RNA after rechallenge by IHGI but was also protected from chronic HCV infection after sequential rechallenge with 100 50% chimpanzee infectious doses of a heterologous type 1a (H77) and 1b (HC-J4) whole-virus inoculum. These results offer encouragement to pursue the development of HCV vaccines.

Amino Acid Sequence↗

Cross protection between an encapsulated strain of Staphylococcus hyicus and encapsulated strains of Staphylococcus aureus.

Strain ST67P of Staphylococcus hyicus grew diffusely in regular serum-soft agar. With the addition of rabbit antisera prepared with Staph. aureus strains, Smith, NS58D or NS41D, capsular type A, B or C, respectively, the organisms converted to compact type growth. Mice immunized with heat-killed vaccine of strain ST67P showed significant resistance against either homologous or heterologous strains, Smith, NS58D and NS41D. Passive protective activities in rabbit antisera prepared with strains Smith, NS58D and NS41D were absorbed out with either homologous cell surface polysaccharide fraction or cell surface polysaccharide fraction extracted from strain ST67P. Well-defined large capsules were observed in ultra-thin sections treated with rabbit antiserum prepared with homologous strain conjugated with ferritin. Also, the capsule surrounded by ferritin granules was shown in ultra-thin sections treated with ferritin conjugated with antisera prepared with those heterologous strains although the capsular size was significantly smaller than those observed by homologous antiserum.

Animals↗

Cross protection against Taenia taeniaeformis in rats vaccinated with non-viable oncospheres of Asian Taenia or T. saginata.

It was determined to examine whether rats injected with non-viable oncospheres of Asian Taenia or Taenia saginata became resistant to challenge infection with eggs of Taenia taeniaeformis, since (a) metacestodes of Asian Taenia and T. taeniaeformis develop in the liver of pigs and rats, respectively, and (b) Asian Taenia and T. saginata have human origins. Rats injected intravenously or subcutaneously with complete Freund's adjuvant with non-viable oncospheres of Asian Taenia showed statistically significant resistance to challenge infection with eggs of T. taeniaeformis, whereas those injected with non-viable oncospheres of T. saginata did not show any resistance.

Animals↗

Changes in host resistance caused by Nocardia brasiliensis in mice: cross-protection against Listeria monocytogenes.

Listeria monocytogenes was used to study the rate of development, magnitude, and persistence of the antimicrobial resistance engendered by Nocardia brasiliensis infection in mice. The growth of Listeria in the liver and spleen was more effectively restricted in Nocardia-infected mice than in noninfected animals. The development of delayed-type hypersensitivity to the Nocardia antigen was closely correlated to the increased resistance to Listeria, suggesting that both properties are the consequence of a single immunological event. The antibacterial resistance was also demonstrated in vitro. The results of the foregoing studies indicate that the microbicidal ability of macrophages, very likely activated by cell-mediated immunity, in enhanced in mice infected with Nocardia.

Animals↗

Cross-protection between the cysts of Echinococcus granulosus, Taenia hydatigena and T ovis in lambs.

Lambs were infected orally at 14 weeks of age with either Taenia hydatigena, T ovis or Echinococcus granulosus eggs. To induce high levels of resistance to oral reinfection, they were then injected intramuscularly with eggs of the homologous species four weeks and eight weeks later. The degree of immunity was then tested by oral challenge with eggs from either the homologous or an heterologous species. Autopsy results indicated that prior infection with an homologous species induced a very high degree of immunity to challenge infection. Prior infection with all combinations of heterologous species resulted in a lesser degree of immunity, which appeared to have acted on the establishment phase of development and did not influence cyst survival.

Animals↗

Antiserum against culture filtrate is cross-protective for various serovars of Erysipelothrix rhusiopathiae.

The protective effect of porcine antiserum prepared against culture filtrate (CF) of an attenuated strain of Erysipelothrix rhusiopathiae (serovar 2) in mice to challenge with 20 virulent strains of 18 serovars and one type N was investigated. Passively immunized mice survived after challenge with serovars 1a, 1b, 2, 5, 6, 8 (strain Goda), 11, 12, 15, 16, 21 or type N, but 10-30% mortality occurred in immunized mice challenged with each strain of serovars 4, 7, 8 (strain 911), 9, 18 or 19 and 70% mortality to serovar 10 (strain 2179). All immunized mice died after challenge with serovar 20 (strain 2553). Non-treated control mice died after challenge with all serovars and the type tested.

Agglutination Tests↗

Immunogenicity of various mycobacteria and the corresponding levels of cross-protection developed between species.

Seven mycobacterial species were tested for their ability to immunize mice against subsequent tuberculous challenge. The phylogenetic relationships between the vaccine and challenge strains had little direct influence on the level of resistance; a better correlation was found between the ability of the vaccine to survive or multiply in vivo and the immunogenicity of the organism. Mycobacterium tuberculosis, M. bovis (except for an SM(R) variant), M. avium, two of three M. kansasii strains, and one strain of M. intracellulare all survived or multiplied in vivo. They induced an effective resistance against a subsequent M. tuberculosis (Erdman) or BCG challenge. The SM(R) BCG, the Bostrom strain of M. kansasii, M. scrofulaceum, three strains of M. intracellulare, and one of M. terrae and M. fortuitum were unable to survive in vivo and were nonallergenic and nonimmunogenic. No evidence was found for an interference phenomenon between the atypical mycobacteria and the BCG vaccine sufficient to explain the inadequate levels of immunization reported in some field trials.

Animals↗

[Cross protection between an encapsulated strain of Staphylococcus hyicus and an encapsulated strain of Staphylococcus epidermidis].

Strain ST67P of Staphylococcus hyicus was capsular type I (++)/II(+) of S. epidermidis as determined by the method of Ichiman. To mice immunized with heat-killed vaccine of strain ST67P, homologous strain and strain ATCC 31432 (capsular type I), SE-360 (capsular type II) and SE-10 (capsular type III) of S. epidermidis were injected intraperitoneally into mice, then, the viable cell number of the organisms in the peritoneal cavity were enumerated of 30 minutes and 20 hours after the injection. Results showed that the viable cell number of the homologous strain and strain ATCC 31432 was remarkably decreased at 20 hours after the injection, however, the cells were increased with strain SE-360 and SE-10. Passive protective activity of rabbit anti-ATCC 31432 serum was absorbed either with homologous strain or strain ST67P in the mouse, however, protective activity of anti-SE-360 strain serum and anti-SE-10 strain serum was not absorbed with these organisms although the activity was absorbed with homologous organisms. With an ultrathin section preparation of strain ST67P conjugated with ferritin-labelled rabbit anti-homologous strain serum, numerous ferritin granules surrounding the outermost layer of large capsule were electronmicro-scopically demonstrated. In the same organisms treated with ferritin-labelled anti-ATCC31432 strain serum, the all walls were surrounded by a relatively thinner capsule and a number of ferritin granules were located in the outermost layer of the capsule. However, with the organisms treated with ferritin-labelled anti-SE-360 strain serum only a number of ferritin granules were shown on the surface of the cell walls, and neither capsule nor ferritin granules were exhibited in the organisms treated with ferritin-labelled anti-SE-10 strain serum.

Animals↗

Onchocerca ochengi: epidemiological evidence of cross-protection against Onchocerca volvulus in man.

In North Cameroon, the vector of Onchocerca volvulus (causative agent of human onchocerciasis) also transmits 2 filariae of animals: O. ochengi from cattle and O. ramachandrini from wart hogs. In order to assess the qualitative and quantitative roles of these 'animal filariae' in the epidemiology of O. volvulus, the transmission of the 3 parasites was measured in 2 villages and related to the endemicity of human onchocerciasis. In Galim, a cattle-farming Guinea savanna village where wild animals are rare, the overwhelming majority of all filarial infections found in the Simulium damnosum s.l. vectors throughout the year were O. ochengi (89%). The remaining infections were mainly O. volvulus (10.5%), and a few O. ramachandrini (0.5%). In Karna, a crop-farming Sudan savanna village where cattle are rare, but wild animals common, flies were also more frequently infected with animal filariae than with the human parasite. In the dry season, when nomadic cattle are present, 54% of all infections were O. ochengi, 36% O. volvulus and 10% O. ramachindrini. In the rainy season, when the cattle move away, flies were mainly infected with O. ramachandrini (52% of all infections) and secondly with O. volvulus (48%). In Karna, the relationship between the Annual Transmission Potential (ATP) of O. volvulus and its prevalence in the human population conformed to other onchocerciasis foci, in that a moderate ATP led to hyperendemic onchocerciasis. In Galim, however, a 7-fold higher O. volvulus-ATP (caused by a very high biting rate of the flies) contrasted with a strikingly low endemicity of onchocerciasis. Since, at the same time, in Galim the transmission of O. ochengi (measured on man) was very high (15,000 L3/fly collector/year), we hypothesize that the reduced endemicity of onchocerciasis in Galim is due to 'natural heterologous vaccination' by the large annual number of O. ochengi-L3, inoculated into man by anthropo-boophilic S. damnosum s.l. The importance of micro-epidemiology for the understanding of the interlinkage of human and animal onchocerciasis is discussed.

Animals↗

Orf virus and vaccinia virus do not cross-protect sheep.

Inoculation of lambs with a New Zealand strain of orf virus (NZ 2) failed to protect them against subsequent infection with the Lister strain of vaccinia virus. Similarly, in the reciprocal test, vaccinia virus failed to protect against subsequent orf virus infection. Inoculation with either orf virus or vaccinia virus alone afforded protection against reinfection with the same virus. These results have relevance to the use of vaccinia virus gene vectors in sheep.

Animals↗

Integration of mutations responsible for the attenuated phenotype of Pepper mild mottle virus strains results in a symptomless cross-protecting strain.

An enhanced attenuated strain of Pepper mild mottle virus (PMMoV) was constructed by incorporating mutations that affect viral attenuation from three reported attenuated strains of PMMoV, which causes serious economic losses in the production of green pepper in Japan. The new strain caused no symptoms on pepper plants and protected them from infection by a wild-type strain. The mutations responsible for viral attenuation were located in the intervening region (IR) of the 126-kDa/183-kDa proteins. The mutations had synergistic effects in terms of the attenuation of symptoms and decreased the accumulation of the viral coat protein in infected pepper plants. In this paper, we propose an efficient method for the improvement of attenuated viruses by reverse genetics in plant viruses.

Base Sequence↗