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At least 433 records · Page 24Linked to original sources
PubMed2006

Randomized, double-blind, placebo-controlled efficacy trial of a bivalent recombinant glycoprotein 120 HIV-1 vaccine among injection drug users in Bangkok, Thailand.

BACKGROUND: In Thailand, phase 1/2 trials of monovalent subtype B and bivalent subtype B/E (CRF01_AE) recombinant glycoprotein 120 human immunodeficiency virus type 1 (HIV-1) vaccines were successfully conducted from 1995 to 1998, prompting the first HIV-1 vaccine efficacy trial in Asia. METHODS: This randomized, double-blind, placebo-controlled efficacy trial of AIDSVAX B/E (VaxGen), which included 36-months of follow-up, was conducted among injection drug users (IDUs) in Bangkok, Thailand. The primary end point was HIV-1 infection; secondary end points included plasma HIV-1 load, CD4 cell count, onset of acquired immunodeficiency syndrome-defining conditions, and initiation of antiretroviral therapy. RESULTS: A total of 2546 IDUs were enrolled between March 1999 and August 2000; the median age was 26 years, and 93.4% were men. The overall HIV-1 incidence was 3.4 infections/100 person-years (95% confidence interval [CI], 3.0-3.9 infections/100 person-years), and the cumulative incidence was 8.4%. There were no differences between the vaccine and placebo arms. HIV-1 subtype E (83 vaccine and 81 placebo recipients) accounted for 77% of infections. Vaccine efficacy was estimated at 0.1% (95% CI, -30.8% to 23.8%; P=.99, log-rank test). No statistically significant effects of the vaccine on secondary end points were observed. CONCLUSION: Despite the successful completion of this efficacy trial, the vaccine did not prevent HIV-1 infection or delay HIV-1 disease progression.

AIDS Vaccines↗
PubMed2003

Specific antibody responses to vaccination with bivalent CM235/SF2 gp120: detection of homologous and heterologous neutralizing antibody to subtype E (CRF01.AE) HIV type 1.

HIV-1 CRF.AE-01 (formerly subtype E) infection is highly prevalent in Southeast Asia. Despite success with public health measures, the development of an effective CRF01.AE vaccine is critical to the control of this epidemic. Sera from the open-label arms of the first clinical trial of a bivalent HIV gp120 SF2/CM235 (subtypes B and CRF.AE-01, respectively) vaccine were evaluated for the presence of gp120-specific binding (BAb) and neutralizing antibody (NAb). Twelve pre- and postvaccination sera pairs were tested for CM235 BAb; anti-gp120 CM235 BAb was found in all postvaccination samples. The 12 pre- and postvaccination (1 month after third vaccination) serum pairs were evaluated in several neutralization formats: heterologous T cell line adapted (TCLA) NP03/H9, homologous CM235/PBMC, CM235/dendritic cell, and CM235M4-C4.6/A3R5. A3R5 is a CCR5+ T cell line, and CM235M4-C4.6 is the homologous CM235 virus adapted to growth in A3R5 cells. All volunteers developed BAb, but meaningful NAb was not demonstrable against primary isolate CM235. Using the TCLA CRF01.AE virus NP03 in H9 cells, 9 of 12 persons had NAb with a geometric mean titer (GMT) of 46. The CM235M4-C4.6 virus in A3R5 cells also detected NAb in 9 of 12 persons, with a GMT of 41. CM235M4-C4.6/A3R5 detected NAb in two persons with negligible NAb to NP03/H9 and vice versa. Whether the NAb detected by the CM235M4-C4.6/A3R5 system is qualitatively different from those in more traditional NP03/H9 assays will require further study.

AIDS Vaccines↗
PubMed1995

A bivalent immunoadhesin of the human interferon-gamma receptor is an effective inhibitor of IFN-gamma activity.

We describe here the bioengineering of a bivalent IFN-gamma-RFc immunoadhesin consisting of the extracellular domain of the human IFN-gamma receptor alpha chain (IFN-gamma-R) fused to a human IgG1 Fc region (encoding hinge, CH2 and CH3 domain) that was efficiently expressed as a covalently linked homodimer in insect cells and purified in a one-step purification procedure. The IFN-gamma-RFc fusion protein exerted a 3-fold higher ligand binding affinity in binding competition studies in vitro compared with the monovalent extracellular IFN-gamma-R domain. In addition, the in vitro antagonistic activity of IFN-gamma-RFc, as determined by inhibition of IFN-gamma-induced virus protection and HLA-DR expression, was more than 30-fold higher in comparison with the monovalent soluble receptor. The described IFN-gamma-R immunoadhesin is a potential therapeutic reagent to interfere with the disease-promoting activities of IFN-gamma in several autoimmune diseases.

Animals↗
PubMed2004

Recombinant bivalent vaccine against foot-and-mouth disease virus serotype O/A infection in guinea pig.

In this study, two DNA fragments encoding amino acid (141-160)-(21-140)-(141-160) of the VP1 of FMDV (foot-and-mouth disease virus) serotype O and (138-160)-(21-40)-(138-160) of the serotype A FMDV were chemically synthesized. These two tandem-repeat fragments were ligated and transfected into prokaryotic expression vector pTrcHis A to construct pTH-O-A. The other vector called pTH-O-scIgG-A was constructed similarly only that the two tandem-repeat DNA fragments were linked by the bovine-IgG heavy chain coding sequence. Guinea pigs immunized with the two bivalent vaccines pTH-O-A and pTH-O-scIgG-A showed both specific antibody activity and T cell proliferation responses. FMDV challenge tests showed that 85% and 70% of guinea pigs vaccinated twice with 200 mg of the fusion protein of pTH-O-A were protected from FMDV serotype O and serotype A infection respectively. 70% and 57% of the guinea pigs immunized with the fusion protein of pTH-O-scIgG-A were protected from FMDV serotype O and serotype A infection respectively.

Animals↗
PubMed1996

Regional bivalent-univalent pairing versus trivalent pairing of a trisomic chromosome in Saccharomyces cerevisiae.

In meiosis I, homologous chromosomes pair, recombine and segregate to opposite poles. These events and subsequent meiosis II ensure that each of the four meiotic products has one complete set of chromosomes. In this study, the meiotic pairing and segregation of a trisomic chromosome in a diploid (2n + 1) yeast strain was examined. We find that trivalent pairing and segregation is the favored arrangement. However, insertions near the centromere in one of the trisomic chromosomes leads to preferential pairing and segregation of the "like" centromeres of the remaining two chromosomes, suggesting that bivalent-univalent pairing and segregation is favored for this region.

Chromosomes, Fungal↗
PubMed1977

Safety and antigenicity of inactivated influenza virus vaccines in children: trials with monovalent and bivalent A/New Jersey/76 (HswN1) and A/Victoria/75 virus vaccines in Washington, D.C..

Safety and antigenicity of monovalent and bivalent A/New Jersey/NJ)/76 (HssN1) and A/Victoria/75 inactivated influenza virus vaccines were studied in 125 children aged three to 18 years. In recruitment, families who knew the study team, who were professionally involved, and/or who were under close continuing care were more likely to volunteer for such studies than those who were unfamiliar with the team or institution. Antibody responses and systemic reactions occurred more often after administration of inactivated whole-virus vaccine than after split-virus vaccine. Significant titers (greater than or equal to 1:40) of hemagglutination-inhibiting antibody to A/NJ/76 virus occurred in 95% of normal children three to 18 years of age who received two doses of the same vaccine (whole or split). However, insufficient numbers of children achieved a reasonable antibody titer (greater than or equal to 1:40) after one dose of vaccine.

Adolescent↗
PubMed1977

Clinical trials of bivalent A/New Jersey/76-A/Victoria/75 influenza vaccines in high-risk children.

Various doses of two whole-virus and one split-product bivalent influenza A/New Jersey/76-A/Victoria/75 vaccines were administered to 253 children aged six to 18 years. There were no statistically significant differences in either reactivity or humoral antibody response among the 167 children in seven chronic disease categories and 86 healthy children. The whole-virus vaccines were associated with unacceptably high rates of reaction when given in sufficiently antigenic initial doses but were relatively nonreactive when used for booster immunization. Split-product vaccines were no more reactive than placebo. All vaccine preparations induced adequate seroconversion rates and protective titers of antibody to A/Victoria virus after one dose and to A/New Jersey virus after two doses.

Adolescent↗
PubMed1977

Response of children with cardiac disease to the bivalent influenza A vaccines.

During the recent nationwide trials of influenza vaccine, 121 children with cardiac disease, aged three to 18 years, were evaluated with respect to their immune response and reaction rate after administration of a whole-virus or split-virus bivalent influenza A/New Jersey/76-A/Victoria/75 vaccine given as a single dose or two divided doses. The serologic response of the cardiac children did not differ significantly from that of the total group of high-risk children or normal children who recived the same vaccine. The major reaction to the vaccines was fever, which occurred in one-fourth to one-half of children receiving the whole-virus vaccines. The split-virus vaccines were generally well tolerated. The reaction index of the cardiac children was slightly lower than that of the normal children receiving the same vaccine during the single-dose trial but higher during the two-dose trial. The second dose was generally better tolerated than the first dose. Reactions in the children with cardiac disease could not be adequately evaluated according to specific diagnoses or functional disabilities.

Adolescent↗
PubMed1977

Reactivity and antibody response to vaccination with bivalent influenza A/Victoria/75-A/New Jersey/76 vaccines in children with chronic pulmonary diseases.

Reactogenicity and antibody responses of high-risk children and adolescents (aged three to 18 years) to bivalent influenza A/Victoria/75-A/New Jersey/76 virus vaccine from nine participating centers were compared to the response of the total population of vaccinees in the multicenter study of the National Institute of Allergy and Infectious Diseases. Split-product vaccines given in two doses four weeks apart offered protection without a significant risk of side effects. Patients with chronic pulmonary disease did not differ from the total study population to antibody response or reactivity to vaccination with A/New Jersey strains.

Adolescent↗
PubMed1977

Multicenter two-dose trials of bivalent influenza A vaccines in asthmatic children aged six to 18 years.

Data from all of the vaccination centers that immunized asthmatic children six to 18 years old with bivalent influenza A/New Jersey/76 and A/Victoria/75 vaccines were analyzed. Systemic reaction indexes were somewhat higher in asthmatic children receiving the first dose of whole-virus vaccines than in similar vaccinees without asthma. Antibody levels after immunization, while different in some instances, did not show any significant trends toward either hypo- or hyperresponsiveness in the asthmatic children.

Adolescent↗
PubMed1997

An engineered bivalent single-chain antibody fragment that increases antigen binding activity.

Bivalent single chain Fv (scFv) was constructed by fusing a polypeptide extension containing one or two cysteines to the COOH-terminus of an scFv antibody fragment. The scFv protein was expressed and secreted in a recombinant Pichia pastoris system as a dimer with a C-terminal disulfide bridge, as determined by Western blot analysis under non-reducing conditions. We found that the scFv construct with one cysteine in the C-extension (scFv-1Cys) exhibited a much higher dimer/monomer ratio than the two cysteine counterpart (scFv-2Cys). Binding activity measurements performed by means of a competitive radioimmunoassay showed that scFv-1Cys exhibited specific antigen binding activity, which was almost the same as that of the parental MAb, and approximately four- and fortyfold higher than those of the control scFv monomer and scFv-2Cys.

Amino Acid Sequence↗
PubMed1994

A randomized comparison of three bivalent Streptococcus pneumoniae glycoprotein conjugate vaccines in young children: effect of polysaccharide size and linkage characteristics.

Because most childhood invasive pneumococcal disease occurs before the age of 2 years, the development of a pneumococcal vaccine that is immunogenic in infants is a priority. We assessed the safety and serum antibody responses to two dose levels of three bivalent pneumococcal capsular polysaccharide (CPS)-protein conjugate vaccines incorporating the poorly immunogenic serotypes 6A and 23F. The conjugate vaccines differed in CPS size and chemical linkage, but all used a nontoxic cross-reactive mutant diphtheria toxin (CRM197) as the protein carrier. 118 young children 18 to 30 months of age received a single immunization with one of the three glycoconjugates or with licensed pneumococcal vaccine. Sera were obtained before and 1 month after immunization and analyzed by enzyme-linked immunosorbent assay for serotype-specific antibody titers. The 23F CPS was more immunogenic than the 6A CPS in all vaccine formats. The most immunogenic 23F conjugate vaccine consisted of native CPS directly linked to the carrier protein; smaller CPS or the use of a six-carbon linker did not appear to enhance immunogenicity in these young children. Conjugation of two pneumococcal CPSs is associated with an increase in immunogenicity, and the characteristics of the CPS and of the CPS-protein linkage appear to influence the antibody response.

Bacterial Vaccines↗
PubMed1997

Safety and immunogenicity of a bivalent Haemophilus influenzae type b/hepatitis B vaccine in healthy infants. Hib-HB Vaccine Study Group.

OBJECTIVE: To assess the safety, tolerability and immunogenicity of COMVAX, a liquid, bivalent Haemophilus influenzae type b-hepatitis B vaccine, containing the polyribosylribitol phosphate (PRP)-Neisseria meningitidis outer membrane protein complex conjugate used in the Hib vaccine, PedvaxHIB, and the yeast-derived hepatitis B surface antigen (HBsAg) used in the HB vaccine, RECOMBIVAX HB. DESIGN: Eight hundred eighty-two healthy infants, approximately 2 months of age, were enrolled in an open, multicenter (n = 11) clinical trial and randomized to receive either COMVAX (7.5 micrograms of PRP/5 micrograms of HBsAg in 0.5 ml) or concurrent injections of the liquid formulation of PedvaxHIB (P) (7.5 micrograms of PRP in 0.5 ml) and RECOMBIVAX HB (R) (5 micrograms of HBsAg in 0.5 ml) at 2, 4 and 12 or 15 months of age. Safety and tolerability were monitored after each injection. The serum concentrations of anti-PRP and anti-HBs were determined at the time of each vaccination, 2 months after the second vaccination and 1 month after the third vaccination. RESULTS: COMVAX was well-tolerated and proved to be immunologically comparable with a series of concomitant P+R injections. There were no serious adverse experiences attributable to the study vaccines. The most commonly reported nonserious adverse experiences were all events prelisted on diary cards given to parents. These included generally mild and transient signs of inflammation at the injection site (pain/ soreness, erythema, swelling/induration), somnolence and irritability. Because children are at peak risk of invasive Hib disease during the first year of life, 6 months of age (2 months after the second dose of vaccine) was designated the time of primary interest with regard to the development of anti-PRP. At that time 94.8% of the infants given COMVAX had > 0.15 microgram/ml of anti-PRP and 72.4% had > 1.0 microgram/ ml, with a geometric mean concentration (GMC) of 2.5 micrograms/ml, compared with 95.2%, 76.3% and 2.8 micrograms/ml, respectively, in recipients of P+R. The third injection given at 12 or 15 months of age induced a secondary rise in antibody. The proportions with > 0.15 microgram/ml and > 1.0 microgram/ml of anti-PRP increased to 99.3 and 92.6%, respectively, and the GMC rose to 9.5 micrograms/ml among COMVAX recipients, compared with 98.9%, 92.3% and 10.2 micrograms/ml in children given concurrent injections of P+R. In contrast to Hib few infants in countries with low endemicity of HBV infection are at near term risk of exposure to virus. Consequently the anti-HBs response after the last dose of vaccine was designated the outcome of primary interest. At 13 to 16 months of age (1 month after the third dose of vaccine) 98.4% of children given COMVAX had a protective anti-HBs concentration of > or = 10 mIU/ml with a GMC of 4468 mIU/ml, compared with 100% and a GMC of 6944 mIU/ml among children given P+R. CONCLUSIONS: COMVAX is well-tolerated by healthy infants and can induce immunity against invasive Hib disease and HBV infection using only three injections compared with six injections if separate courses of monovalent PedvaxHIB and RECOMBIVAX HB are given.

Antibodies, Bacterial↗
PubMed2004

Concomitant administration of a bivalent Haemophilus influenzae type b-hepatitis B vaccine, measles-mumps-rubella vaccine and varicella vaccine: safety, tolerability and immunogenicity.

BACKGROUND: The study was done to verify that concomitant administration of a bivalent Haemophilus influenzae type b-hepatitis B vaccine (Comvax), measles-mumps-rubella vaccine (M-M-RII) and varicella vaccine (Varivax) would be well-tolerated and suitably immunogenic with respect to all vaccine antigens. METHODS: We randomized 822 healthy 12- to 15-month-old children (1:1) to receive concomitant injections of Comvax, M-M-RII and Varivax (concomitant group) or Comvax followed 6 weeks later by injections of M-M-RII and Varivax (nonconcomitant group). Blood samples taken before and 6 weeks after vaccination were tested for antibodies to all vaccine antigens. RESULTS: Vaccinations were generally well-tolerated. Children in the concomitant and nonconcomitant treatment groups were similar with respect to the safety endpoint of primary interest (16.1 and 19.5%, respectively, had a fever > or =103 degree F rectally at any time within 14 days after either of two clinic visits). Fifteen serious adverse events were reported (eight in the concomitant group and seven in the nonconcomitant group); all resolved. Elements of two serious adverse events (fever, fever and measles-like rash; both in concomitant group children) were considered possibly related to vaccination. One child was withdrawn from the study because of a nonserious adverse event subsequently judged to be unrelated to vaccination. Similar proportions of vaccinees in the concomitant and nonconcomitant groups developed satisfactory antibody responses to the H. influenzae polysaccharide, polyribosylribitol phosphate (97.8 to 98.7%), hepatitis B surface antigen (99.2 to 100%), measles virus (99.4 to 99.6%), mumps virus (98.4 to 99.2%), rubella virus (100%) and varicella virus (93.2 to 94.6%). CONCLUSION: Concomitant administration of Comvax, M-M-RII and VARIVAX at the 12- or 15-month clinic visit is one satisfactory way of delivering some of the multiple vaccines indicated during the second year of life.

Antibodies, Viral↗
PubMed2006

Stochastic models of receptor oligomerization by bivalent ligand.

In this paper, we develop stochastic models of receptor binding by a bivalent ligand. A detailed kinetic study allows us to analyse the role of cross-linking in cell activation by receptor oligomerization. We show how oligomer formation could act to buffer intracellular signalling against stochastic fluctuations. In addition, we put forward the hypothesis that formation of long linear oligomers increases the range of ligand concentration to which the cell is responsive, whereas formation of closed oligomers increases ligand concentration specificity. Thus, different physiological functions requiring different degrees of specificity to ligand concentration would favour formation of oligomers with different lengths and geometries. Furthermore, provided that ligand concentration specificity is taken as a design principle, our model enables us to estimate parameters, such as the minimum proportion of receptors, that must engage in oligomer formation in order to trigger a cellular response.

Computer Simulation↗
PubMed2001

SWITCH1 (SWI1): a novel protein required for the establishment of sister chromatid cohesion and for bivalent formation at meiosis.

We have characterized a new gene, SWI1, involved in sister chromatid cohesion during both male and female meiosis in Arabidopsis thaliana. A first allele, swi1.1, was obtained as a T-DNA tagged mutant and was described previously as abnormal exclusively in female meiosis. We have isolated a new allele, swi1.2, which is defective for both male and female meiosis. In swi1.2 male meiosis, the classical steps of prophase were not observed, especially because homologs do not synapse. Chromatid arms and centromeres lost their cohesion in a stepwise manner before metaphase I, and 20 chromatids instead of five bivalents were seen at the metaphase plate, which was followed by an aberrant segregation. In contrast, swi1.2 female meiocytes performed a mitotic-like division instead of meiosis, indicating a distinct role for SWI1 or a different effect of the loss of SWI1 function in both processes. The SWI1 gene was cloned; the putative SWI1 protein did not show strong similarity to any known protein. Plants transformed with a SWI1-GFP fusion indicated that SWI1 protein is present in meiocyte nuclei, before meiosis and at a very early stage of prophase. Thus, SWI1 appears to be a novel protein involved in chromatid cohesion establishment and in chromosome structure during meiosis, but with clear differences between male and female meiosis.

Alleles↗
PubMed1990

Evidence of neuropeptide bivalency in the interaction of substance P with cerebroside sulfate.

A precipitin effect has been observed with mixtures of cerebroside sulfate and the neuropeptide substnace P. This phenomenon is attributed to multivalency of the lipid due to its existence in micellar form, and to bivalency of substance P. One of those neuropeptide sites is almost certainly the basic residue(s) located at the N-terminal of substance P, whereas the hydrophobic residues at the C-terminus are suggested as candidates for the other site on the basis of turbidimetric, circular dichroic, and fluorometric studies. An intrinsic association constant of 3.6 x 10(4)M-1 has been obtained from the cerebroside sulfate concentration associated with maximal turbidity of mixtures containing a fixed concentration of the neuropeptide.

Binding Sites↗
PubMed1990

Antigens recognized by the human immune response to vaccination with a bivalent hardjo/pomona leptospiral vaccine.

Serum from volunteer subjects vaccinated with a bivalent whole cell vaccine of Leptospira interrogans serovar hardjo/serovar pomona grown in protein-free medium, was tested by the microscopic agglutination test (MAT), enzyme-immunoassay (EIA) and immunoblotting. Specific IgM antibodies to either serovars hardjo or pomona were detected in some subjects as early as 6 days after vaccination with peak antibody levels occurring 13-68 days after vaccination. Whereas all subjects produced specific IgM to both serovars, not all produced specific IgG to both serovars. Immunoblotting with hardjo sonicate revealed that all subjects produced IgM antibodies reacting with the 15, 23 and 28 kDa components of hardjo lipopolysaccharide (LPS), and most produced IgM antibodies that reacted with the 34.5 kDa flagellar doublet. In contrast, not all sera immunoblotted against pomona sonicate reacted with the 29 and 35 kDa components of pomona LPS. However all subjects produced antibodies reacting with a diffuse 14.4-27 kDa band. These antibodies appeared early in the immune response. Serum from the one vaccinated subject tested protected hamsters from acute lethal infection with serovar pomona.

Agglutination Tests↗