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PubMed1987

Immunogenic variants of a murine fibrosarcoma induced by mutagenesis: requirement of viable cells for antigen-specific cross-protection.

The purpose of the study was to investigate the immunological and biological consequences of neoantigen expression by immunogenic tumor variants (Imm+) following in vitro treatment with the mutagen 1-methyl-3-nitro-1-nitrosoguanidine. The weakly immunogenic murine fibrosarcoma MCA-F was used because we have previously characterized the tumor-specific transplantation antigen expressed by this tumor. Immunogenic variant clones were obtained at high frequency following four treatments with 1-methyl-3-nitro-1-nitrosoguanidine. The immunogenicity of the Imm+ clones was confirmed by their progressive growth in immunosuppressed C3H/HeN mice and their lack of growth in normal syngeneic (C3H/HeN mice. The immune response engendered in immunocompetent mice after a single immunization with viable Imm+ cells was tumor specific, completely protecting hosts against challenge with 10,000-fold the minimum tumorigenic dose of parental MCA-F cells, but not against 10 minimum tumorigenic doses of the non-cross-reactive tumor MCA-D. The strong cross-protection elicited by Imm+ neoantigens against the parental tumor-specific transplantation antigen was not observed when soluble extracts or isolated plasma membranes of Imm+ cells were used for immunization. Immunogenic variant cells inactivated using either mitomycin C or gamma-irradiation also demonstrated a significantly diminished immunoprotective activity against challenge with the parent tumor. However, inactivated Imm+ cells and their isolated plasma membranes still expressed sufficient neoantigen to completely protect mice against homotypic Imm+, but not parental challenge. These results suggest that (a) the MCA-F Imm+ variants express neoantigens capable of engendering a strong specific as well as cross-protective immunity against challenge with either the parent or the variant and (b) the associative recognition of neoantigen and TSTA that results in strong cross-protection against challenge with the parent tumor requires immunization with viable Imm+ cells for full expression of the immunogenic phenotype.

Animals↗

PubMed1991

Immunity to Onchocerca volvulus microfilariae in mice and the induction of cross-protection with O. lienalis.

Inbred CBA/Ca mice were vaccinated with Onchocerca volvulus or Onchocerca lienalis microfilariae (mf) and challenged 100 days later with the homologous or heterologous parasite. There was a major reduction in mf recoveries from immunised animals compared with controls when the sensitising and challenge infections were both of O. volvulus mf. Resistance was manifest within one week of challenge, and rose from an 87% reduction in recoveries on day 7 to a 96% reduction on day 15. Similar results were obtained for homologous sensitising and challenge infections with O. lienalis mf. Protection afforded by sensitisation with the heterologous parasite was also high, although the expression of resistance appeared to be delayed. Vaccination with O. lienalis mf led to a 45% level of cross-protection against O. volvulus at 7 days after challenge, which rose to 94% by day 15. Vaccination with O. volvulus mf stimulated cross-protection against O. lienalis at levels of 49% and 80% as measured 7 and 15 days after challenge. It is concluded that the mouse model may be of value in analysing immune responses directed against O. volvulus mf and that the cross-protection between Onchocerca species is an advantage that should be exploited in characterising the antigens involved.

Animals↗

PubMed1978

Cross-protection in mice after immunization with H2N2, H3N2, and Heq2Neq2 influenza virus strains.

Mice were vaccinated with the influenza viruses A/Japan/57 (H2N2), A/Hong Kong/68 (H3N2), and A/Equi/Miami/63 (Heq2Neq2) and the hemagglutinin and neuraminidase recombinants derived from these viruses. After infection with the parent viruses, protection was compared with serological findings. It was found that influenza vaccine protects not only against infection with a strain identical or closely related to the vaccine strain, but against heterologous strains as well. Vaccination with Hong Kong/68 and its neuraminidase recombinant resulted in a heterologous neuraminidase inhibition titer against Japan/57 and in a protection against infection with Japan/57. By contrast, after vaccination with Japan/57 and its neuraminidase recombinant, no relevant heterologous neuraminidase inhibition titer against Hong Kong/68 was observed, whereas a protection against infection with Hong Kong/68 did exist. A cross-protection between Hong Kong/68 and Miami/63, but no relationship in the hemagglutination or neuraminidase inhibition tests, was established in the preinfection sera. A one-way antigenic relationship between these viruses was confirmed by the rise of hemagglutinin or neuraminidase antibodies against Hong Kong/68 in the postinfection sera. No cross-protection or serological relationship existed between Miami/63 and Japan/57. Besides the hemagglutinin and neuraminidase, a third factor, the "mouse-protecting antigen," was considered to contribute to the protection obtained. According to the protection observed, the mouse-protecting antigen of Hong Kong/68 virus is related to that of Japan/57 as well as Miami/63 virus. The mouse-protecting antigens of both Japan/57 and Miami/63 are related to that of Hong Kong/68.

Animals↗

PubMed1987

Intraspecific cross-protection in mice immunized with irradiated Schistosoma mansoni cercariae.

Several laboratory-maintained strains of Schistosoma mansoni were tested for their relative immunogenicity or susceptibility to anti-schistosome immunity in irradiated cercaria-immunized mice. A total of 11 strains and substrains were used; 7 were of Puerto Rican origin, 3 from Brazil, and 1 from Egypt. Mice were immunized by percutaneous exposure to 50-krad-irradiated cercariae. Immunity was assessed following challenge with cercariae of the homologous or a heterologous strain. The results showed that the choice of either the challenge or immunizing strains was not critical in the development of significant levels of protection. Extensive degrees of cross-protection developed in all intrastrain combinations tested.

Animals↗

PubMedDate not supplied

[Method for the cross protection of mice in studying the antigenic variability of the influenza virus].

A modification of the method of cross protection of mice was developed for the study of influenza virus antigenic drift. This modification does not require a pre-adaptation of the virus to mouse lungs. The experiments of cross protection of immune animals carried out by the modified method demonstrated antigenic variability of the influenza A virus strains (H3N2) isolated in 1968-1983. Immunologically significant differences between influenza A/Hong Kong/68/ and A/Victoria/36/72 virus strains were detected. Subsequently, with isolation of more influenza virus strains immunologically significant differences were found between A/Victoria/36/72 and A/Leningrad/42/75 (an analogue of A/Scotland/840/74) strains, A/Leningrad/42/75 and A/Leningrad/399/76 (an analogue of A/Victoria/3/75) strains. The differences between influenza A/Texas/1/77 and A/Leningrad/527/80 (an analogue of A/Bangkok/1/79), A/Leningrad/385/80 (an analogue of A/Bangkok/1/79), and A/Leningrad/50/83, (an analogue of A/Philippines/2/82) strains were not immunologically significant.

Animals↗

PubMedDate not supplied

Cross-protection factor(s) of Pasteurella multocida: passive immunization of turkeys against fowl cholera caused by different serotypes.

An antiserum cross-protective against different serotypes of Pasteurella multocida was made in turkeys by inoculating them with killed serotype 3 organisms grown in vivo and then exposing them to live serotype 3 organisms. In passive-immunization studies, the antiserum protected young turkeys against the homologous and heterologous serotypes 1, 4, 5, 9, and 12. In addition, the antiserum protected against P. multocida of a heterologous capsule serogroup, serogroup F. A globulin and two IgG fractions purified from the antiserum protected against heterologous challenge with serotype 1. Turkey-grown P. multocida were chemically lysed and separated into soluble and insoluble components to make immunoadsorbents. Antibodies from the cross-protective antiserum isolated by the immunoadsorbents passively protected young turkeys against heterologous serotype I challenge.

Animals↗

PubMed1992

Epitopes of group A streptococcal M protein that evoke cross-protective local immune responses.

The present studies were undertaken to identify conserved epitopes of group A streptococcal M proteins that evoke cross-protective mucosal immune responses. Two synthetic peptides copying conserved regions of type 5 M protein, designated SM5(235-264)C and SM5(265-291)C, were covalently linked to carrier molecules and their immunogenicity was tested in laboratory animals. Rabbit antisera against both peptides cross-reacted with multiple serotypes of group A streptococci, indicating that the peptides contained broadly cross-reactive, surface exposed M protein epitopes. Serum antipeptide antibodies adsorbed to the surface of heterologous type 24 streptococci passively protected mice against intranasal challenge infections. Mice that were actively immunized intranasally with each synthetic peptide covalently linked to the B subunit of cholera toxin were protected against colonization and death after intranasal challenge infections with type 24 streptococci in the absence of serum opsonic antibodies. These data confirm and extend previous observations that conserved M protein epitopes evoke cross-protective local immunity and may serve as the basis for broadly cross-protective M protein vaccines.

Amino Acid Sequence↗

PubMedDate not supplied

Modulation of cross-protection factor(s) of avian Pasteurella multocida.

Cross-protection factor(s) (CPF) of Pasteurella multocida were maintained in vitro through at least 9 serial passages. Different growth media and temperatures enhanced or repressed the ability of P. multocida to produce CPF. Certain amino acids were innoculous to expression of CPF. B-vitamins enhanced CPF, whereas certain inorganic salts repressed CPF. The plasma of normal tuekeys contained a compound or compounds that were responsible for expression and maintenance of CPF.

Animals↗

PubMed1975

Preliminary evidence for cell-mediated immunity in cross-protection among group A arboviruses.

Unfractionated and T cell-enriched populations from spleens of mice immunized with Sinbdis virus confer cross-protection against Semliki forest virus challenge in recipient mice. Both Group A viruses are serologically related, but not by tests for cross-neutralizing antibody. The protection in mice persisted for three consecutive cell passages in uninfected mice. The results suggest that cell-mediated immunity accounts for cross-protection.

Animals↗

PubMedDate not supplied

Pathogenicity and cross-protection of pigeon paramyxovirus-1 and Newcastle disease virus in young chickens.

Avian paramyxovirus-1 (PMV-1) isolates from Delaware racing pigeons were compared with Newcastle disease virus (NDV) in pathogenicity and cross-protection studies in young chickens. The pathogenicity of pigeon PMV-1 isolates was more closely related to mesogenic (Roakin) NDV than to lentogenic (La Sota) or velogenic (Texas GB) NDV strains. Pigeon PMV-1 produced 100% mortality in 1-day-old NDV-susceptible chickens following intratracheal and intracerebral inoculation. Laboratory tests often used in conjunction with chicken pathogenicity procedures for patho-typing NDV gave conflicting results. Pigeon PMV-1 isolates produced large clear plaques (up to 3.5 mm) in chicken-embryo-fibroblast cultures. Chicken embryo mean death times were considerably greater for pigeon PMV-1 (88 and 109 hr) than for Roakin (66 hr) and Texas GB (48 hr). B1 strain NDV and pigeon PMV-1 produced complete cross-protection in challenge studies in chickens. Extensive cross-reaction between pigeon PMV-1 and NDV occurred in hemagglutination-inhibition tests using polyclonal antisera. However, pigeon PMV-1 and NDV were readily distinguishable using a NDV monoclonal antibody, 2F12.

Animals↗

PubMed1991

An evaluation of the cross-protection afforded by inactivated infectious coryza vaccines.

The cross-protection afforded by three inactivated infectious coryza vaccines was evaluated. Each vaccine contained one of the following strains of Haemophilus paragallinarum, HP31, HP60 and HP14. Strain HP31 belongs to Kume serovar C-2, strain HP60 belongs to Kume serovar C-4 while strain HP14 belongs to Kume serovar A-4. Four groups of twenty six-week-old specific-pathogen-free chickens were either given a single dose of an aluminium-hydroxide based vaccine (three groups) or left as unvaccinated controls. Three weeks after vaccination, all four groups were challenged with virulent H paragallinarum. One half of each group was challenged with the strain HP31 and the other half with strain HP60. The efficacy of the vaccines was assessed in terms of the prevention of the typical clinical signs and macroscopic lesions of infectious coryza as well as the prevention of any colonisation by the challenge organism. The serovar C-2 and serovar C-4 vaccines protected more than 50% of birds against either a serovar C-2 or C-4 challenge while the serovar A-4 vaccine protected less than 50% of birds.

Animals↗

PubMed1991

Analysis of immune responses of different hosts to Babesia divergens isolates from different geographic areas and capacity of culture-derived exoantigens to induce efficient cross-protection.

The immunoprecipitation of [35S]methionine-radiolabelled antigens from different Babesia divergens isolates by using bovine, gerbil, and human immune sera has shown that many B. divergens proteins contain epitopes shared between isolates. The cross-protective capacity of culture-derived soluble immunogens from the B. divergens Rouen 1987 isolate was tested against different B. divergens isolates. Results showed complete protection against the 7107b French isolate and substantial protection against the Weybridge 8843 English isolate (80% protection) and the Munich 87 German isolate (60% protection). In order to explain these vaccination results and to assess both the common and variable antigenicity of B. divergens, the antigenic patterns of the challenge isolates (Rouen 1987, 7107b, Weybridge 8843, and Munich 87) were compared by immunoprecipitation, using gerbil antisera raised against the Rouen 1987 vaccine isolate. Differences in the antigenic patterns and in the cross-protection of gerbils in these heterologous challenges were examined by studying the virulence and the antigenic status of each isolate.

Animals↗

PubMed1989

Characterization of variant and parental-cross-protective immunity to immunogenic variants of a murine fibrosarcoma using the local adoptive transfer assay.

The purpose of this study was to characterize the lymphocyte populations responsible for rejection of immunogenic (Imm+) tumor variants, and the cross-protective immunity engendered by Imm+ variants against the weakly immunogenic parental tumor. Immunogenic clones of the weakly immunogenic methylcholanthrene-induced fibrosarcoma MCA-F have been generated using 1-methyl-3-nitro-1-nitrosoguanidine, 5-aza-2'-deoxycytidine, or ultraviolet radiation (UV-B; 280-320 nm). These clones grow progressively in immunosuppressed adult-thymectomized irradiated mice, but are rejected by immunocompetent syngeneic hosts. The parental MCA-F tumor grows progressively in both groups. Mice that have rejected a challenge of 1 x 10(5) Imm+ cells show an anamnestic immune response against both the Imm+ clone and the parental MCA-F tumor. Using the local adoptive transfer assay and depletion of T-cell subsets with antibody plus complement, we show that immunity induced by the Imm+ variants against the parent MCA-F was mediated by the Thy1.2+, L3T4a+ population without an apparent contribution by Lyt2.1+ cells. Although antivariant immunity was also dependent upon Thy1.2+ cells, depletion of either the L3T4a+ or the Lyt2.1+ cells failed to abolish immunity against the variant. A role for Lyt2.1+ T lymphocytes in antivariant immunity, but not antiparent immunity, was supported by the results of cytotoxic T lymphocyte (CTL) assays. Following immunization with high numbers (1 x 10(5) to 5 x 10(5) of viable Imm+ cells, antivariant, but not antiparent CTL activity was detected in mixed lymphocyte tumor cell cultures. Immunization with lower numbers (3 x 10(4] of viable Imm+ or with high numbers of mitomycin-C-treated Imm+ engenders only antivariant immunity without parental cross-protection. Under these conditions lymphocytes mediating immunity against the variant in the local adoptive transfer assay were exclusively of the Thy1.2+, L3T4a+ phenotype, with no contribution from the Lyt2.1+ cells. Identical results were obtained for Imm+ clones of MCA-F induced by methylnitronitrosoguanidine, 5-azadeoxycytidine, and UV-B, suggesting that the nature of the antitumor immunity engendered by Imm+ is not significantly affected by the agent used. Furthermore, these results demonstrate that the cross-reactivity and cellular effectors of antitumor immunity in this system are influenced by the immunizing dose of Imm+ cells: the predominant effectors of both antivariant and parental-cross-reactive immunity were of the CD4+ T cell subclass, with a CD8+ cytotoxic population contributing to antivariant immunity only after high-dose immunization.

Animals↗

PubMedDate not supplied

Solubilization of membrane-associated cross-protection factor(s) of Pasteurella multocida.

Pasteurella multocida harvested from the blood of turkeys dying of experimental fowl cholera were purified by centrifugation and lysed. The soluble and membrane-associated components of the bacteria were separated by centrifugation. Nonionic (octylglucoside) and zwitterionic (3-[(3-cholamidopropyl) dimethylammonio]-1-propanesulfonate; CHAPS) detergents were tested for their abilities to solubilize the cross-protection factor(s) (CPF) from the membrane-associated component. Protection studies in turkeys showed that optimum solubilization was by 1.0% octylglucoside and 0.5% CHAPS. Antibodies from turkeys made against solubilized membrane-associated CPF passively cross-protected poults against challenge. Ion exchange chromatography of detergent-solubilized CPF resulted in elution of two protein-containing peaks, each of which conferred active immune protection.

Animals↗

PubMed1992

Stress proteins and cross-protection by heat shock and salt stress in Bacillus subtilis.

Bacillus subtilis induced a set of general stress proteins in response to a salt or heat stress. Cells subjected to a mild heat stress showed a protective response which enabled them to survive otherwise lethal temperatures (e.g. 52 degrees C). In a similar way bacteria were enabled to survive toxic concentrations of NaCl by pretreatment with lower salt concentrations. A mild heat shock induced a cross-protection against lethal salt stress. The pretreatment of cells with low salt, however, was less effective in the induction of thermotolerance than a preceding mild heat stress. Three stress proteins were identified on the basis of their N-terminal amino acid sequences as homologues of GroEL, DnaK and ClpP of Escherichia coli. The role of general and specific stress proteins in the induction of thermotolerance/salt tolerance and cross-protection is discussed.

ATP-Dependent Proteases↗

PubMed1989

Cross-protective immunity between equine encephalomyelitis viruses in equids.

Eighteen equids were inoculated with eastern equine encephalomyelitis (EEE) and 18 equids with western equine encephalomyelitis (WEE) viruses to produce EEE virus- and WEE virus-immunized equids. Twelve surviving EEE virus-seropositive equids, 15 surviving WEE virus-seropositive equids, and 10 nonimmunized, seronegative equids (controls) were subsequently inoculated with an equine pathogenic (epizootic) strain of Venezuelan equine encephalomyelitis (VEE) virus to determine cross-protective immunity. Challenge infection produced 90% mortality in control (nonimmunized) equids, and 40% mortality in WEE virus-seropositive equids; all EEE virus-seropositive equids survived. Postchallenge exposure VEE viremia levels in EEE virus- or WEE virus-seropositive equids were lower than those in the 10 nonimmunized VEE virus-inoculated control equids. Plaque-neutralizing antibody responses to VEE virus in the EEE virus- and WEE virus-seropositive equids were similar in time of onset and titer to the antibody responses of nonimmunized equids. Neutralizing antibody to the third equine encephalomyelitis virus (either EEE virus or WEE virus) was detectable in 19 of 27 equids after inoculation with the challenge virus, VEE. Demonstration of cross-protective immunity between EEE or WEE virus and VEE virus in equids confirmed field observations made during the VEE epizootic in Texas in 1971.

Alphavirus↗

PubMed1987

Surface antigens of and cross-protection between two geographical isolates of Schistosoma mansoni.

Two isolates of Schistosoma mansoni from Puerto Rico and Egypt were examined to determine if there were differences in surface antigens of the schistosomulum and to assess the ability of the two isolates to induce protection against one another in vivo. Immune mouse and human patient antisera recognized the same antigens on the schistosomulum surface of both isolates. However, mice immunized with schistosomula-released products from the Egyptian isolate recognized an additional antigen of Mr 13K on the Egyptian schistosomulum surface which was not present in the Puerto Rican isolate. In quantitative radioimmunoassay, sera from mice vaccinated with irradiated Egyptian cercariae bound more strongly to Egyptian schistosomula than to Puerto Rican parasites. Both isolates cross-protected against each other, but mice were less immune to challenge with Egyptian cercariae after being immunized with Puerto Rican irradiated cercariae. There was no difference in immunity to challenge when Egyptian irradiated cercariae were used to immunize. Although this evidence suggested some heterogeneity within the Egyptian isolate, cloned cercariae of the Egyptian isolate did not vary in their ability to cross-protect against each other. Furthermore, antisera from mice immunized with clones of Egyptian cercariae recognized the same schistosomulum surface antigens. The results reported here indicate that although there were small differences between the two isolates the major surface antigens are conserved.

Animals↗

PubMed1979

Differentiation of Mycoplasma mycoides subsp. mycoides from certain closely related caprine mycoplasmas by mycoplasmaemia and cross-protection tests in mice.

In recent years, mycoplasma taxonomists have found that numerous mycoplasma strains from goats are serologically indistinguishable from Mycoplasma mycoides subsp. mycoides, the causative agent of contagious bovine pleuropneumonia (CBPP), by routinely used tests, e.g. the metabolism- and growth-inhibition tests. As a result, such organisms are now openly referred to as M. mycoides subsp. mycoides. Seven of these so-called M. mycoides subsp. mycoides strains from goats were compared with two strains of M. mycoides subsp. mycoides from CBPP, and with one strain of M. mycoides subsp. capri, by means of two in-vivo tests, namely, (1) a test of the ability of each strain, injected intraperitoneally into mice, to produce mycoplasmaemia, and (2) a cross-protection test in mice. Of the seven strains, only one ('O goat') was indistinguishable from genuine M. mycoides subsp. mycoides; it also had small colonies resembling those of genuine M. mycoides subsp. mycoides. The other six were easily distinguished from genuine M. mycoides subsp. mycoides, and they produced large colonies. These six strains and others like them should no longer be given a name that fails to distinguish them from the causative agent of CBPP. Cross-protection tests showed that the seven goat strains referred to above differed from M. mycoides subsp. capri.

Animals↗