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At least 235 records · Page 13Linked to original sources
PubMed2006

Cross-protection against homologous drift variants of influenza A and B after vaccination with split vaccine.

The aim of this serological study was to demonstrate the extent to which antibodies react against subsequent drift variants, after vaccination with split vaccine (Fluarix). Antibody titers have been determined by hemagglutination inhibition test (HI) against different influenza A and B drift variants in sera from three past multicenter trials. Individuals of two different age groups, i.e. 18-60 years and above 60 years, were enrolled. Vaccine components influenza A/H1N1 and influenza B of Fluarix show a high degree of cross immunogenicity against subsequent homologous drift variants. The genetically more variable component influenza A/H3N2 shows somewhat lower protection rates. High levels of cross immunogenicity were found between the variants of influenza A/Panama/2007/99 (H3N2) and influenza A/Wyoming/3/2003 (H3N2). The results demonstrate that in situations where drift variants emerge too late to be included in the influenza vaccine formulation, the cross-protection conferred must be evaluated on a case-by-case basis.

Adolescent↗
PubMed2000

Reciprocal cross-protection induced by sporozoite antigens SPAG-1 from Theileria annulata and p67 from Theileria parva.

Theileria annulata and Theileria parva both possess a major surface antigen on the sporozoite stage of the life-cycle, called SPAG-1 and p67, respectively. In each case, these antigens are vaccine candidates and have been shown to induce a degree of homologous protection in earlier work. These antigens share sequence homology and are serologically cross-reactive. Here, we confirm that these antigens confer protection against homologous species challenge. More importantly, they mutually confer a degree of cross-species protection raising the prospect of a common vaccine in the future.

Animals↗
PubMed1990

Cross-protection against influenza B type virus infection by intranasal inoculation of the HA vaccines combined with cholera toxin B subunit.

The relationship between the antibody responses to various influenza B type virus HA vaccines and protection against live B virus infection was investigated in Balb/c mice which had been inoculated intranasally with a combination of the HA vaccines and B subunit of cholera toxin (CTB) 4 weeks previously. The inoculation of HA vaccine, prepared from B/Ibaraki/2/85 (B/Ibaraki), B/Nagasaki/1/87 (B/Nagasaki) or B/Aichi/5/88 (B/Aichi) viruses, combined with CTB induced high levels of both nasal IgA and serum HI antibodies to any of B/Ibaraki, B/Nagasaki and B/Aichi viral antigens. Simultaneous inoculation of each CTB-combined HA vaccine provided complete protection against B/Ibaraki virus infection which is demonstrated by both rapid clearance of pulmonary virus and complete survival. On the other hand, the inoculation of HA vaccine prepared from B/Yamagata/16/88 (B/Yamagata) virus together with CTB induced only a low level of nasal IgA antibodies, cross-reactive to B/Ibaraki, B/Nagasaki and B/Aichi viral antigens and protected only partially against B/Ibaraki virus challenge. The involvement of the B type virus-specific immunity in this protection was suggested by the absence of protection against B/Ibaraki virus infection in mice previously inoculated with both A/PR/8/34 (H1N1) virus HA vaccine and CTB. These results suggest that antibodies to various influenza B viruses are cross-reactive to each B type virus antigens and that cross-protection against B virus infection could be conferred depending on the degree of B type virus cross-reactive immunity including secretory IgA antibodies.

Animals↗
PubMed1991

Cross-protection against influenza A virus infection by passively transferred respiratory tract IgA antibodies to different hemagglutinin molecules.

Mice that were intranasally immunized with different influenza A virus hemagglutinins (HA), derived from PR8 (H1N1), A/Yamagata (H1N1) or A/Fukuoka (H3N2) virus, together with cholera toxin B subunit as an adjuvant, were examined for protection against PR8 infection; PR8 HA and A/Yamagata HA immunization conferred complete protection, while A/Fukuoka HA immunization failed to confer protection. In parallel with protection, PR8 HA-, A/Yamagata HA-, and A/Fukuoka HA-immunized mice produced a high, a moderate and a low level of PR8 HA-reactive IgA in the respiratory tract, respectively. These IgA antibodies were not only higher in content in the nasal secretions, but also more cross-reactive than IgG. The purified IgA antibodies from respiratory tract washings of PR8 HA-immunized mice, which contained the HA-specific IgA corresponding to the amount detected in the nasal wash, were able to protect mice from PR8 challenge when transferred to the respiratory tract of naive mice. The transfer of IgA from A/Yamagata HA-immunized mice also afforded cross-protection against PR8 infection, whereas the IgA from A/Fukuoka HA-immunized mice failed to provide protection. The ability of transferred IgA to prevent viral infection was dependent on the amount of HA-reactive IgA remaining in the respiratory tract of the host at the time of infection. These experiments directly demonstrate that IgA antibodies to influenza A virus HA by themselves play a pivotal role in defence not only against homologous virus infection, but also against heterologous drift virus infection at the respiratory mucosa, the portal of entry for the viruses.

Animals↗
PubMed2003

Protective efficacy of oral immunization with heat-killed Shigella flexneri 2a in animal model: study of cross protection, immune response and antigenic recognition.

Oral immunization of rabbits with four doses of 10(11) heat-killed Shigella flexneri 2a showed 100% protection against challenge with virulent S. flexneri 2a. After orally immunizing Guinea pigs with four doses of heat-killed S. flexneri 2a 100% protection could be shown against ocular challenge with the same virulent S. flexneri 2a strain but this conferred no protection against challenge with Shigella dysenteriae type 1. In enzyme-linked immunosorbent assay (ELISA) and immunoblot experiments both whole cell lysate-envelope (WCL-E) fraction and outer membrane proteins (OMPs) were recognized by the antisera. Though protective mechanism in shigellosis is not established with certainty, outer membrane proteins (specially 38, 34, 23 and 20kDa proteins) may be the major antigens in the induction of protective immune responses as indicated by this observation.

Administration, Oral↗
PubMed2004

Genetic relationships, serological cross-reaction and cross-protection between H1N2 and other influenza A virus subtypes endemic in European pigs.

This study examines the genetic relationships between the recently emerged H1N2 swine influenza virus and viruses of H1N1 and H3N2 subtypes, and the extent of protection against H1N2 challenge in pigs immune after infection or vaccination with the other subtypes. There was low amino acid homology (70.4-71.9%) in the haemagglutinin (HA) gene between H1N1 viruses used for primary infection or vaccination and the H1N2 challenge strain, with 94-99 amino acid changes between these viruses involving all five antigenic sites. The NA genes of H3N2 viruses used for primary infection or vaccination showed higher amino acid homology with H1N2 (88.3-92.6%), while nucleoprotein (95.5-96.3% nucleotide identity) and matrix (96.8-98.4%) genes were most conserved between the three subtypes. Pigs immune as a result of intranasal inoculation with either H1N1 or H3N2 showed partial clinical protection against H1N2 challenge, and nasal virus excretion was 2 days shorter than in naive pigs. Moreover, dually infected (H1N1 + H3N2)-immune pigs showed complete clinical protection and H1N2 virus replication in the lungs and nasal secretions was either undetectable or markedly reduced. In contrast, a double vaccination with a commercial H1N1 and H3N2-based vaccine did not protect against H1N2 challenge. Haemagglutination inhibition (HI) or virus neutralisation (VN) tests of swine sera revealed little if any antigenic cross-reactivity between subtypes. These data suggest that serum HI or VN antibodies are not essential in heterosubtypic protection, but that mucosal or cellular immunity are probably involved. It is still unknown whether this type of cross-subtype protection will also occur in infection-immune pigs in the field.

Animals↗
PubMed1984

Immunity to Babesia in mice. II. Cross protection between various Babesia and Plasmodium species and its relevance to the nature of Babesia immunity.

Mice immunized against B. rodhaini by means of a drug-controlled infection were subsequently resistant to infection with B. microti and B. ratti. In the reciprocal experiments the protection against B. rodhaini was less effective. B. rodhaini immunized mice were also considerably protected against P. vinckei infection, whereas protection against P. berghei did not occur. Antibody determinations indicated that the heterologous protection cannot be explained by the occurrence of cross-reacting antibodies. Because of similarity with the non-specific suppression of babesiosis in BCG-infected mice, the same effector mechanism is postulated to explain the infection-induced homologous and heterologous protection. Unlike non-specifically induced protection, the induction of acquired resistance by means of a drug-controlled B. rodhaini infection is thymus-dependent.

Animals↗
PubMed1975

Fowl cholera; cross-protective turkey antisera and IgG antibodies induced with Pasteurella multocida-infected tissue bacterins.

Turkey antisera induced with formolized Pasteurella multocida-infected tissues (T antisera) passively cross-immunized 48 of 55 chickens against a challenge dose of P. multocida organisms, from which 0 of 15 controls survived. However, turkey antisera induced with formalin-killed, agar-cultured P. multocida cells (A antisera) passively cross-immunized only 4 of 30 chickens. Cross-immunity refers to protection against a different immunologic type of P. multocida. Quantitative precipitin reactions of the A and T antisera with antigens from agar-cultured cells showed that more antibody was present in the A than in the T antisera. However, antigens extracted from the infected tissues reacted with the T and not with the A antisera in the Ouchterlony procedure, demonstrating qualitative differences between the agar-cultured antigens and those extracted from the infected tissue. The gel precipitins isolated from the A and T antisera were characterized as 7S immunoglobulins, which behaved in immunoelectrophoresis as would be expected for a IgG immunoglobulin. The IgG fraction from the T antiserum passively cross-immunized chickens almost as well as the whole antiserum; hence, the IgG antibody is a major factor in cross-immunity.

Animals↗