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At least 631 records · Page 35Linked to original sources
PubMed1989

Complement-independent neutralising monoclonal antibody with differential reactivity for strains of human cytomegalovirus.

A mouse monoclonal antibody with complement-independent neutralising activity against cytomegalovirus (CMV) and reactive with the 86 kilodalton (kDa) viral glycoprotein H is described. Neutralisation tests against a range of different strains of CMV showed significant crossreactivity, but clear differences were evident between the two prototype viruses AD169 and Davis, and particularly between AD169 and several low-passage recent clinical isolates; CMV present in urine was neutralised weakly if at all.

Animals↗
PubMed1999

A human anti-HIV autoantibody enhances EBV transformation and HIV infection.

A highly specific, human IgG mAb, F223, which reacts with both HIV-1-infected cells and uninfected lymphoid cells, has been derived. F223 reacts with gp120 but fails to neutralize viral infection. The antibody does enhance HIV-1 infection in a complement-dependent manner. The autoantigen recognized by F223 is expressed on a small percentage of T cells and NK cells and the majority of B cells. Immunoprecipitation demonstrates F223 reactivity with an as of yet unidentified 159-kDa protein in uninfected lymphoid cells. This reactivity with uninfected cells is inhibited by free gp120 demonstrating the cross-reactive nature of this antibody. The F223 light chain demonstrates strong homology to VLlambda2 family genes whereas the heavy chain is most homologous (84%) to the germline gene VH3-H.11. In vivo usage of VH3 family genes by F223 and an anti-HIV-1 (gp41) human mAb, 3D6, with related autoreactivity, suggests that VH3 sequences may be important components of potentially pathogenic human anti-HIV-1 envelope autoantibodies. F223 was isolated from an HIV-1 infected individual with lymphoma and in vitro F223 significantly enhances EBV transformation of normal B cells and increases immunoglobulin production without affecting B cell proliferation. Characterization of this antibody response may provide important insights and mechanistic information on HIV pathogenesis.

Antibodies, Blocking↗
PubMed1993

Neutralization determinants of United States bluetongue virus serotype ten.

A panel of five neutralization-resistant escape mutant (EM) viruses was used to investigate the neutralization determinants of the U.S. prototype strain of bluetongue virus serotype 10 (BTV-10). The phenotypic properties of each EM virus were characterized by neutralization and immuneprecipitation assays with a panel of four monoclonal antibodies (MAbs). These MAbs were used to select the various EM viruses and together the MAbs define four distinct neutralizing epitopes on the prototype strain of BTV-10 (Heidner, H.W., Rositto, P.V., and MacLachlan, N.J., Virology 176, 658-661 (1990)). Sequencing of the L2 gene identified mutations responsible for the altered phenotypic properties exhibited by each EM virus. The L2 gene encodes BTV outer capsid protein VP2 which is responsible for virus neutralization. Four amino acids in three distinct regions of VP2 are critical to expression of the epitopes recognized by the MAb panel. Both amino acid 208 and 211 can affect the binding of MAb 039 and MAb 045, amino acid 327 affects binding of MAb 041, and amino acids 327 and 402 cooperatively interact to affect binding by MAb 034. The location of two of these critical regions on VP2 of BTV-10 is identical to two of those which affect neutralization of Australian BTV-1, despite the fact that these two viruses are antigenically distinct and have divergent L2 gene sequences (Gould, A.R., and Eaton, B.T., Virus Res. 17, 161-172 (1990)). The four individual neutralizing epitopes on VP2 of BTV-10 are interactive (Heidner, H.W., Rositto, P.V., and MacLachlan, N.J., Virology 176, 658-661 (1990)) and at least two are conformationally dependent.

Antibodies, Monoclonal↗
PubMed1993

Antigenic variation of molecularly cloned SIVmac239 during persistent infection in a rhesus macaque.

Eight rhesus macaques inoculated with molecularly cloned SIVmac239 developed viremia and virus-binding antibodies, but only one (macaque 2D) developed neutralizing antibodies to the virus. Viremia persisted in macaque 2D even in the presence of neutralizing antibodies. Neutralizing antibodies in the plasma collected from macaque 2D late in infection neutralized virus isolated early in infection. In contrast, these antibodies failed to neutralize the plasma viruses isolated after the appearance of neutralizing antibodies. Only antigenic variants were isolated from blood, spleen, and lymph nodes. Viruses isolated from other macaques that did not develop neutralizing antibodies were neutralized by 2D serum and were of the parental (SIVmac239) phenotype. The variant viruses maintained their strict tropism for lymphocytes, similar to the parental virus.

Animals↗
PubMed1993

Epitope mapping studies with neutralizing and non-neutralizing monoclonal antibodies to the G1 and G2 envelope glycoproteins of Hantaan virus.

Epitopes recognized by three G1-specific and two G2-specific neutralizing monoclonal antibodies to Hantaan virus were mapped by sequence analyses of the complete M genome segments of neutralization escape variant viruses. For each variant, we detected nucleotide sequence substitutions which resulted in a single amino acid change in either the G1 or G2 protein. Serological properties of the variant viruses correlated with changes identified by nucleotide sequence analyses. To map epitopes recognized by three G1-specific and six G2-specific, non-neutralizing monoclonal antibodies, we prepared genes, truncated at the carboxy terminal coding regions of G1 or G2, and expressed them with baculovirus recombinants or transiently in a vaccinia/T7 RNA polymerase system. Reactivities of the monoclonal antibodies with the truncated proteins were monitored by immune precipitation of the radiolabeled, truncated glycoproteins. We determined that all three of the G1-specific antibodies reacted with truncated proteins, which retained the amino terminal one-third of G1, but lost reactivity with shorter G1 proteins. The G2-specific antibodies only recognized G2 proteins, which retained approximately 80% of the G2 gene.

Amino Acid Sequence↗
PubMed1994

Virulence-associated antigenic and genetic characteristics of bluetongue virus-17 isolates.

Bluetongue virus (BLU), an orbivirus, is of importance to the sheep and cattle industries. We have obtained 5 United States BLU-17 isolates which have been tested for virulence in sheep and 16 BLU-17 field isolates from the Caribbean and Central America. Using a panel of 15 monoclonal antibodies (MAb) against an avirulent BLU-17, we observed that 6 MAbs had negligible or very low neutralization titers for the virulent isolates in contrast to moderate to high titers for the avirulent isolates. These MAbs also differentiated the field isolates into two groups--inadequate vs effective neutralization. All 6 MAbs immunoprecipitated the outer capsid protein, VP2. Electropherotyping of genomic RNA from all 21 viruses identified an increase in RNA segment 3 mobility for those isolates which were not neutralized by the 6 specific MAbs. RNA segment 3 codes for the inner core protein, VP3. There were no detectable electrophoretic differences for RNA segment 2, which encodes VP2. In summary, the virulent BLU-17 isolates differed from the avirulent isolates in both the antigenicity of the outer capsid protein, VP2, and the electrophoretic mobility of RNA segment 3, and we hypothesize that one or both of these changes may result in BLU virulence.

Animals↗
PubMed1994

African swine fever virus structural protein p72 contains a conformational neutralizing epitope.

We have previously described a monoclonal antibody (mAb 135D4) to an unidentified 70- to 72-kDa African swine fever virus (ASFV) protein that exhibited high levels of neutralizing activity against various virulent ASFV isolates. Here, we identify the reactive ASFV protein as the major virus structural protein p72. In vitro-translated products of the p72 protein gene were specifically immunoprecipitated by mAb 135D4. Immunoprecipitation of a nested set of truncated p72 in vitro translation products defined the region between amino acid residues 400 and 404 as necessary for mAb 135D4 reactivity. Five partially overlapping peptides (15mers) covering residues 388-446 failed to react with mAb 135D4, suggesting the conformational dependence of the epitope. Supporting this interpretation, larger in vitro translation products representing residues 56-282, 159-361, 360-508, and 507-646 also failed to react with mAb 135D4. Consistent with its involvement in virus neutralization, immunoelectromicroscopy, using a rabbit antiserum against mAb 135D4-purified p72, located the protein on the surface of unenveloped virus particles.

African Swine Fever Virus↗
PubMed1995

Homotypic and heterotypic neutralization determinants of bluetongue virus serotype 17.

Homotypic and heterotypic neutralization determinants of bluetongue virus serotype 17 (BTV-17) were investigated with a panel of five neutralizing monoclonal antibodies (MAbs). One MAb (MAb 034) was originally raised to BTV serotype 10 (BTV-10) but also neutralizes BTV-17 (P. V. Rossitto, and N. J. MacLachlan, 1992, J. Gen. Virol. 73, 1947-1952). Competitive binding studies indicate that the MAbs recognize at least two epitopes on the neutralizing outer capsid protein VP2 of BTV-17. The MAbs were used to select neutralization-resistant variant [escape mutant (EM)] viruses and to determine the phenotypic characteristics of these EM viruses by immunoprecipitation and neutralization assays. Sequencing of the L2 gene, which encodes VP2, identified mutations responsible for the altered phenotypic properties exhibited by each EM virus. Four amino acids in three regions of VP2 are critical to the expression of the epitopes recognized by the panel of neutralizing MAbs. Amino acid 199 affects the binding of MAbs 17.82, 17.83, and 17.813; amino acid 213 affects the binding of MAb 17.85; and amino acids 327 and 582 synergistically affect the binding of MAb 034. Similarly, amino acids 327 and 402 synergistically affect the binding of MAb 034 to BTV-10 (C. D. DeMaula, H. W. Heidner, P. V. Rossitto, C. M. Pierce, and N. J. MacLachlan, 1993, Virology 195, 292-296), suggesting that the neutralizing epitope common to BTV-10 and BTV-17 has a similar location in VP2 of these two antigenically distinct viruses.

Animals↗
PubMed1999

Production and characterization of human monoclonal antibody Fab fragments to vaccinia virus from a phage-display combinatorial library.

A combinatorial, phage-display library of human Fab antibody fragments was generated from IgG heavy chain (HC) and light chain (LC) genes cloned from the lymphocytes of a vaccinia virus (VACV)-immune donor. To ascertain the complexity of the library, nucleotide sequences of the variable regions of the HC and LC genes were determined. Fourteen distinct HC and 18 distinct LC (7 kappa and 11 lambda) that formed a combinatorial library of 22 Fabs were identified. Immune-precipitation of radiolabeled VACV revealed that at least six different VACV proteins were recognized by the antibodies. Plaque-reduction neutralization demonstrated that six of the Fabs neutralized VACV in the presence of anti-human antibody. ELISA studies indicated that 15 of the Fabs were cross-reactive with monkeypox virus.

Amino Acid Sequence↗
PubMed1981

Antigenic relationships of coronaviruses detectable by plaque neutralization, competitive enzyme linked immunoabsorbent assay, and immunoprecipitation.

The antigenic relationships of mouse coronaviruses JHM and A59, human viruses OC43 and 229E, and multiple sclerosis (MS) isolates SD and SK have been investigated by plaque neutralization, competitive enzyme linked immunoabsorbent assay, and immunoprecipitation. A59, SK, or SD plaques are neutralized by antiserum prepared against homologous as well as heterologous virus. Plaque neutralization also demonstrated weak reactivity between SD or SK and mouse virus JHM but no reactivity with human coronavirus 229E. An antiserum prepared against human virus OC43 neutralized viruses SD and SK but not mouse viruses A59 or JHM. In a competitive enzyme linked immunoabsorbent assay (cELISA) the binding of antiserum prepared against MS isolate SK to bound SK antigen was inhibited to a comparable degree using OC43, SD, or A59 viral antigens. Coronavirus 229E or uninfected cell antigens did not block the binding of anti-SK serum to bound antigen. However, a cELISA utilizing OC43 as bound antigen and competing an anti-OC43 serum suggests that virus OC43 may be more closely related to SK than A59. Specific viral polypeptides that share antigenic determinants have been identified by immunoprecipitation of S35 methionine labeled viral infected cell extracts. Polypeptides of similar molecular weight were precipitated from A59, SD, or SK infected cell extracts by SD, SK, OC43, or A59 antisera. Our data suggests that the mouse coronavirus A59, human coronavirus OC43, and MS isolates SD and SK contain antigenically related polypeptides of similar molecular weight.

Animals↗
PubMed1993

Biology and neurobiology of Borna disease viruses (BDV), defined by antibodies, neutralizability and their pathogenic potential.

Borna disease viruses (BDV) isolated from more than 20 naturally infected horses, 2 sheep and a possible feline isolate were included in these studies. Most of these wild-type viruses were grown in rabbit cells. Specifically rabbit-adapted viruses establish persistent infection in immortalized cell lines of various animal species. Brain-, tissue culture-, and cell-free released viruses could all be neutralized with antibodies from naturally and experimentally infected animals (horse; hamster, rat, rabbit, mouse, and chicken), with highest titres in birds. Splenectomized rabbits, which were subsequently infected with BDV, efficiently produced high titres of neutralizing antibodies. All of the neutralizing sera and cerebrospinal fluids from infected animals inhibited tissue culture spread of BDV. Experimental infection and hyperimmunization induced antibodies directed against the major components of the soluble antigen (60, 40/38, 25 and 14.5 kD proteins). Analysis of the s-antigen complex with these sera and 6 stable monoclonal antibodies revealed that it consists of 40/38 and 25 kD proteins. Although each of these antibodies detected intracellular virus-specific structures they did not recognize outer plasma membrane antigens, showed no cross-reactivity, and had no neutralizing capacity. Unifying pathogenetic concepts of this neurotropic virus and its structural elements are discussed.

Animals↗
PubMed1988

The application of immunoperoxidase staining for the detection of causative fungi in tissue specimens of mycosis I.

This study was performed in order to identify the fungi of four species (Aspergillus fumigatus, Fusarium anthophilum, Candida albicans, Cryptococcus neoformans) in formalin-fixed, paraffin-embedded tissue sections by the indirect method of immunoperoxidase staining. Mature albino rabbits were immunized by formalin-killed organisms. The antibodies were prepared by precipitation at a 50% saturation of ammonium sulfate and were checked for cross-reactivities by Ouchterlony's double immunodiffusion and precipitin test. The immunoperoxidase staining was applied to the paraffin-embedded tissue sections of infected mice, human autopsy and biopsy specimens. Although each fungus was stained clearly the cell wall, cross-reactivities appeared among them, however it was possible to identify four fungi by absorption and dilution of the antisera.

Animals↗
PubMed1982

Isolation of 80S ribosomes from spores of Aspergillus fumigatus and their antigenicity in rabbits.

Ribosomes were obtained from spores of Aspergillus fumigatus by mechanical disruption and differential centrifugation. The initial preparation (crude ribosomes) contained spore components which appeared to be broken fragments of plasmalemma with or without organelles. Purified ribosomes free of membranous material were prepared by gel filtration chromatography on Sepharose CL-4B. Monomeric 80S ribosomes consisting of 40% protein and 60% RNA, and morphologically characteristic of fungal ribosomes were isolated. Serological reactions in sera from rabbits with crude or purified ribosomes were similar indicating that the purification process did not change or eliminate antigens that stimulated antibody detectable either by indirect hemagglutination (IHA) or in gel precipitin tests.

Animals↗