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At least 91 records · Page 5Linked to original sources
PubMed1999

Bactericidal and cross-protective activities of a monoclonal antibody directed against Neisseria meningitidis NspA outer membrane protein.

The cross-bactericidal and cross-protective activities of a monoclonal antibody (MAb) named Me-7, which is directed against an antigenically highly conserved epitope on the meningococcal NspA protein, were studied. This MAb efficiently killed in vitro, in the presence of rabbit or human serum, 13 of 14 meningococcal strains tested, including 9 of 9, 2 of 3, and 2 of 2 strains of serotypes B, A, and C, respectively. MAb Me-7 also significantly reduced by more than 75% the levels of bacteremia recorded for mice challenged with 10 of 11 meningococcal strains tested. Analysis of the predicted amino acid sequence of the NspA protein from the meningococcal strain MCH88 (A:4:P1.10), which was not killed by MAb Me-7, indicated the presence of an additional glutamine residue at position 73, compared to the three other NspA sequences. The data presented in this study suggest that antibodies directed against this highly conserved outer membrane protein could protect against meningococcal infections.

Amino Acid Sequence↗
PubMed1991

Cross-protection against four species of chicken coccidia with a single recombinant antigen.

A cDNA clone, SO7', from an Eimeria tenella cDNA library was inserted into the high-expression vector pJC264 and was expressed in Escherichia coli as a fusion protein, CheY-SO7', with a molecular mass of approximately 36 kDa. By using the purified recombinant antigen to immunize young chicks, it was demonstrated that a single dose, without adjuvant, not only protected against severe coccidiosis induced by infection with E. tenella but also protected chicks challenged with the heterologous species Eimeria acervulina, E. maxima, and E. necatrix. By using rabbit antiserum raised against recombinant CheY-SO7', Western blot (immunoblot) analysis of sporulated oocysts of all seven major species of chicken coccidia showed that all species tested contained proteins characteristic of the B class of antigens, of which CheY-SO7' is representative. It seems likely that a single B antigen could protect chickens against severe coccidiosis caused by infection with any of these Eimeria species. Although chicks exposed to prolonged, natural infection develop antibodies to B antigen, active immunization of young chicks with a protective dose of CheY-SO7' does not elicit a humoral antibody response, suggesting that the partial protection results from cell-mediated effector mechanisms. In addition, the cross-protective nature of the immunity indicates that the response to B antigen is different from that induced by natural infection, which elicits a species-specific immunity. To date, the protection induced by B antigen immunization, although remarkable for a single recombinant protein, is not sufficient to compete with prophylactic chemotherapy.

Animals↗
PubMed1978

Cross-protection of mice provided by active and passive immunization against experimental infections with virulent Proteus rettgeri and Providencia bacteria.

Immunization with Providencia and Proteus rettgeri Formalin-treated bacterial suspensions produced high levels of protection in mice against homologous and heterologous challenge. Mice were also cross-protected, but less effectively, by passive administration of rabbit type-specific antisera. The protective activity appeared to be due to an antigen common to strains of different O-serotypes. It was not detectable in agglutination reactions, and preliminary results indicate that it is thermostable, not being inactivated in its antibody binding capacity at 121 degrees C for 1 h.

Animals↗
PubMed1998

Coat protein interactions involved in tobacco mosaic tobamovirus cross-protection.

To investigate the molecular role of the tobacco mosaic tobamovirus (TMV) coat protein (CP) in conferring cross-protection, a potato X potexvirus (PVX) vector (S. Chapman, Plant J. 2, 549-557, 1992) was used to systemically express a set of TMV mutant CPs in Nicotiana benthamiana prior to challenge inoculation with TMV. PVX-expressed wild-type TMV CP delayed TMV accumulation for up to 2 weeks compared to unprotected plants or plants preinfected with the unmodified PVX vector. Similar delays in TMV accumulation were obtained using TMV CPs that were deficient in virion formation but competent to assemble into helical aggregates. In contrast, TMV CPs that were incapable of helical aggregation or unable to bind viral RNA did not delay the accumulation of TMV. Furthermore, TMV CPs with enhanced intersubunit interactions that favor helical aggregation produced significantly greater delays in the accumulation of challenge TMV than obtained from the wild-type CP. Thus the capabilities of TMV CP to interact with viral RNA and self-associate in a helical fashion appear to be essential to its ability to confer protection. Taken together, these findings support a model for CP-mediated resistance in which the protecting CP recoats the challenge virus RNA as it disassembles.

Capsid Proteins↗
PubMed1999

Strategy for cross-protection among Shigella flexneri serotypes.

Based upon the lipopolysaccharide (LPS) structure and antigenicity of Shigella group B, a strategy for broad cross-protection against 14 Shigella flexneri serotypes was designed. This strategy involves the use of two S. flexneri serotypes (2a and 3a), which together bear the all of the major antigenic group factors of this group. The novel attenuated strains used in these studies were S. flexneri 2a strain CVD 1207 (DeltaguaB-A DeltavirG Deltaset1 Deltasen) and S. flexneri 3a strain CVD 1211 (DeltaguaB-A DeltavirG Deltasen). Guinea pigs were immunized with an equal mixture of these strains and later challenged (Sereny test) with a wild-type S. flexneri serotype 1a, 1b, 2b, 4b, 5b, Y, or 6 strain of demonstrated virulence in the same model. Guinea pigs that were immunized with these two vaccine strains produced serum and mucosal antibodies that cross-reacted with all the S. flexneri serotypes tested (except of S. flexneri serotype 6) as assessed by enzyme-linked immunosorbent assay, immunoblotting, and slide agglutination. Furthermore, the combination vaccine conferred significant protection against challenge with S. flexneri serotypes 1b, 2b, 5b, and Y but not with serotypes 1a, 4b, or (as predicted) 6.

Animals↗
PubMedDate not supplied

[Lassa and Mozambique viruses: cross protection in experiments on mice and action of immunosuppressants on experimental infections].

The pathogenicity of Mozambique virus for random-bred mice and CBA mice was studied. In contrast to Lassa virus, intracerebral inoculation of newborn zandom-bred mice with Mozambique virus (1000 PFU/mouse) results in death of the animals. The pathogenic properties of both viruses for adult CBA mice were found to be similar: intracerebral inoculation of the viruses caused death of the animals within 6-8 days, but not intraperitoneal inoculation. With the latter, they produced a population of immunocompetent cells protecting syngeneic recipient mice against the lethal intracerebral inoculation of the homologous virus. Cross-protection experiments demonstrated that intraperitoneal inoculation of Lassa virus protected 70% of mice against the lethal infection with Mozambique virus, and intraperitoneal inoculation of Mozambique virus protected 45% of mice against Lassa virus. Cyclophosphamide exerted no protective effect in Mozambique virus-infected mice. Cyclosporin A exerted no therapeutic effect in mice lethally infected with Lassa or Mozambique virus.

Animals↗
PubMed1987

Immunization of salmonids against Yersinia ruckeri: significance of humoral immunity and cross protection between serotypes.

Brook trout (Salvelinus fontinalis) were immunized with bacterins containing either Serotype 1 or 2 isolates of Yersinia ruckeri to determine the relative degree of cross-protection afforded when the fish were challenged with the homologous or heterologous serotype. While fish immunized with pH-lysed bacterins produced highly specific agglutinins that did not cross-react with antigens derived from a heterologous serotype of Y. ruckeri all fish were protected against experimental challenge, regardless of which serotype was used for bacterin production and experimental challenge. Other experiments indicated that brook trout injected intraperitoneally with highly specific antibodies could not be passively immunized against experimental challenge.

Animals↗
PubMed1994

Cross-protection between species of the Schistosoma haematobium group induced by vaccination with irradiated parasites.

Mice vaccinated with irradiated cercariae of Schistosoma haematobium, S. bovis and S. margrebowiei showed good levels of resistance (38-62%) against an homologous challenge, and varying degrees of resistance (19-46%), against challenges with closely related species. No protection against S. mansoni was induced by vaccination with any of these species. This restricted cross-protection reflects the close phylogenetic relationship between species of the S. haematobium group and indicates that immunologically important epitopes are conserved within this species complex.

Animals↗
PubMed1977

Infectious coryza: in vivo growth of Haemophilus gallinarum as a determinant for cross protection.

Four strains of Haemophilus gallinarum representing 3 immunotypes were used in exposure and challenge exposure studies to determine if in vivo growth of the organism would induce cross protection in chickens. Birds which recovered from infection to 1 immunotype were refractory to reinfection with the heterologous immunotype. In contrast, in vitro-produced bacterins produced immunotype-specific protection.

Animals↗
PubMedDate not supplied

Cross-protection between Tacaribe complex viruses. Presence of neutralizing antibodies against Junin virus (Argentine hemorrhagic fever) in guinea pigs infected with Tacaribe virus.

Cross-protection between Junin virus and five other Tacaribe complex viruses and the serological response of guinea pigs inoculated with Tacaribe virus are reported here. Previous infection with Tamiami or Pichinde viruses significantly delayed guinea pig deaths. A 58% survival rate was found among animals immunized with three doses of Amapari virus, while guinea pigs inoculated with one dose of Machupo or Tacaribe virus were fully protected against Junin virus. Neutralization tests performed in serum samples of guinea pigs immunized with five doses of Tacaribe virus showed that they developed monologous and heterologous neutralizing antibodies.

Animals↗
PubMed1992

[Practice observations of cross protection between bovine and porcine herpesviruses].

In many cattle herds in Lower Saxony the serologic IBR/IPV = BHV-1-status is known because since 1988 the bovine herpes virus infection (BHV 1), the infectious rhinotracheitis and pustular vulvovaginitis (IBR/IPV) are being fought. Through extensive investigations in five districts in the Weser-Ems area, it was found that cows infected by bovine herpes virus (BHV 1) are also protected to a high degree against infection by porcine herpes suis virus (SHV 1). An interpretation of the observed cross protection is not yet possible; further research is necessary.

Animals↗
PubMed1977

Infectious coryza: cross-protection studies, using seven strains of Haemophilus gallinarum.

Bacterins prepared from 7 strains of Haemophilus gallinarum were used to immunized chickens for cross-protection studies. Three distinct immunotypes were distinguished. Slight protection between immunotypes was evident for some strains. Airsacculitis could be prevented by use of these bacterins; however, prevention was related to immunotype specificity. Hyaluronic acid found in 2 strains rendered them inagglutinable in homologous antiserums. Treatment with hyaluronidase rendered them agglutinable.

Agglutination Tests↗
PubMed1995

Parasite strain specificity of precursor cytotoxic T cells in individual animals correlates with cross-protection in cattle challenged with Theileria parva.

Class I major histocompatibility complex-restricted parasite-specific cytotoxic T lymphocytes (CTL) are known to be a major component of the bovine immune response to the protozoan parasite Theileria parva, but formal proof for their role in protection of cattle against infection with T. parva has been lacking. Animals immunized with one stock of T. parva show variations in the degree of protection against heterologous challenge and also in the parasite strain specificity of their CTL responses. The present study investigated the relationship of strain specificity of CTL responses and cross-protection in an effort to verify the role of CTL in protection. The parasite strain specificity of the CTL responses generated in 23 cattle immunized with either of two immunologically distinct parasite populations was examined, and the susceptibility of individual cattle to challenge with the heterologous parasite population was determined. The frequency of stock-specific or cross-reactive CTL precursor cells (CTLp) in individual animals was measured by a limiting-dilution microassay. A proportion of animals immunized with either parasite exhibited cross-reactive CTLp, whereas CTLp detected in the remaining animals were specific for the homologous parasite. On challenge with the heterologous stock, those animals with cross-reactive CTLp were solidly protected while those with strain-specific CTLp showed moderate to severe reactions, although many of them recovered. The finding of a close association between strain specificity of the CTL response and protection against challenge provides strong evidence that CTL are important in mediating immunity.

Animals↗
PubMed1982

Cross-protection in nonhuman primates against Argentine hemorrhagic fever.

The susceptibility of the marmoset Callithrix jacchus to Tacaribe virus infection was investigated to perform cross-protection studies between Junin and Tacaribe viruses. Five marmosets inoculated with Tacaribe virus failed to show any signs of disease, any alterations in erythrocyte, leukocyte, reticulocyte, and platelet counts or any changes in hematocrit or hemoglobin values. No Tacaribe virus could be recovered from blood at any time postinfection. Anti-Tacaribe neutralizing antibodies appeared 3 weeks postinfection. The five Tacaribe-infected marmosets and four noninfected controls were challenged with the pathogenic strain of Junin virus on day 60 post-Tacaribe infection. The former group showed no signs of disease, no viremia, and no challenge virus replication, whereas the control group exhibited the typical symptoms of Argentine hemorrhagic fever, high viremia, and viral titers in organs. Soon after challenge, the Tacaribe-protected marmosets synthesized neutralizing antibodies against Junin virus. These results indicate that the marmoset C. jacchus can be considered an experimental model for protection studies with arenaviruses and that the Tacaribe virus could be considered as a potential vaccine against Junin virus.

Animals↗
PubMed1995

HIV-1 recombinant poxvirus vaccine induces cross-protection against HIV-2 challenge in rhesus macaques.

Rhesus macaques were immunized with attenuated vaccinia or canarypox human immunodeficiency virus type 1 (HIV-1) recombinants and boosted with HIV-1 protein subunits formulated in alum. Following challenge with HIV-2SBL6669, three out of eight immunized macaques resisted infection for six months and another exhibited significantly delayed infection, whereas all three naive controls became infected. Immunizations elicited both humoral and cellular immune responses; however, no clear correlates of protection were discerned. Although more extensive studies are now called for, this first demonstration of cross-protection between HIV-1 and -2 suggests that viral variability may not be an insurmountable problem in the design of a global AIDS vaccine.

AIDS Vaccines↗
PubMed1992

Cross protection studies on Bordetella bronchiseptica in mice using an intracerebral challenge model.

Protective activities of heat-inactivated (60 degrees C for 30 min) merthiolate preserved Bordetella bronchiseptica and B. pertussis bacterins were compared in intraperitoneally immunized mice challenged intracerebrally (i.p./i.c.) or intraperitoneally (i.p./i.p.). In the i.p./i.c. assay (Kendrick test), a B. pertussis bacterin protected mice against challenge with B. pertussis 18-323, as well as against phase I cytotoxic and non-cytotoxic strains of B. bronchiseptica. A B. bronchiseptica bacterin, prepared from a phase I cytotoxic strain, gave protection against two phase I B. bronchiseptica strains, irrespective of their cytotoxin-production. A non-cytotoxic phase I strain of B. bronchiseptica elicited protection against the homologous strain only. Neither cytotoxic nor non-cytotoxic B. bronchiseptica strains protected mice challenged with B. pertussis 18-323. Vaccines prepared from phase III strains of B. bronchiseptica were not protective at all against any of the challenge strains. No such differences in the protective activities of the bacterins could be detected by the i.p./i.p. method. They seem to cross-protect equally well. The results indicate that the Kendrick test may be useful in testing potency of different B. bronchiseptica bacterins.

Animals↗
PubMed1989

Avian infectious bronchitis: cross-protection studies using different Australian subtypes.

The cross-immunity of vaccinated chickens after challenge with some Australian infectious bronchitis viruses was assessed by humoral antibody responses and by ciliary activity in tracheal rings of vaccinated chickens following challenge. Four viruses were used for vaccination: Vac 3, Vac 4, both current infectious bronchitis vaccine viruses, and Q1/76 and N2/62. IBV N1/62 (synonym T0 and infectious bronchitis virus N9/74 (synonym Appin) were used to challenge the vaccinated chickens. Results showed a lack of correlation between humoral antibody levels and protection. Cross-immunity was found after vaccination with each subtype, but was lower for Vac 3 and Vac 4 than for Q1/76 and N2/62.

Animals↗