Susette Audet

The fusion glycoprotein of human respiratory syncytial virus facilitates virus attachment and infectivity via an interaction with cellular heparan sulfate.

ABSTRACT Human respiratory syncytial virus (RSV) F glycoprotein (RSV-F) can independently interact with immobilized heparin and facilitate both attachment to and infection of cells via an interaction with cellular heparan sulfate. RSV-glycosaminoglycan (GAG) interactions were evaluated using heparin-agarose affinity chromatography. RSV-F from A2- and B1/cp-52 (cp-52)-infected cell lysates, RSV-F derived from a recombinant vaccinia virus, and affinity-purified F protein all bound to and were specifically eluted from heparin columns. In infectivity inhibition studies, soluble GAGs decreased the infectivity of RSV A2 and cp-52, with bovine lung heparin exhibiting the highest specific activity against both A2 (50% effective dose [ED50] = 0.28 ± 0.11 μg/ml) andcp-52 (ED50 = 0.55 ± 0.14 μg/ml). Furthermore, enzymatic digestion of cell surface GAGs by heparin lyase I and heparin lyase III but not chondroitinase ABC resulted in a significant reduction in cp-52 infectivity. Moreover, bovine lung heparin inhibited radiolabeled A2 and cp-52 virus binding up to 90%. Taken together, these data suggest that RSV-F independently interacts with heparin/heparan sulfate and this type of interaction facilitates virus attachment and infectivity.

Antiproliferative action of interferon-alpha requires components of T-cell-receptor signalling

Signal transduction through both cytokine and lymphocyte antigen receptors shares some common pathways by which they initiate cellular responses, such as activation of mitogen-activated protein kinase(s),. However, other signalling components appear to be uniquely coupled to each receptor. For example, the interferon receptors transduce regulatory signals through the JAK/STAT pathway, resulting in an inhibition of growth and of antiviral effects, whereas this pathway apparently plays no role in T-cell-receptor (TCR)-dependent gene expression,. Conversely, signal transduction through the TCR requires the tyrosine kinases Lck and ZAP-70 and the tyrosine phosphatase CD45 (ref. 5). Here we show that, unexpectedly, transmission of growth-inhibitory signals by interferon-α (IFN-α) in T cells requires the expression and association of CD45, Lck and ZAP-70 with the IFN-α-receptor signalling complex.

Antibody Induced by Immunization with the Jeryl Lynn Mumps Vaccine Strain Effectively Neutralizes a Heterologous Wild-Type Mumps Virus Associated with a Large Outbreak

Recent mumps outbreaks in older vaccinated populations were caused primarily by genotype G viruses, which are phylogenetically distinct from the genotype A vaccine strains used in the countries affected by the outbreaks. This finding suggests that genotype A vaccine strains could have reduced efficacy against heterologous mumps viruses. The remote history of vaccination also suggests that waning immunity could have contributed to susceptibility. To examine these issues, we obtained consecutive serum samples from children at different intervals after vaccination and assayed the ability of these samples to neutralize the genotype A Jeryl Lynn mumps virus vaccine strain and a genotype G wild-type virus obtained during the mumps outbreak that occurred in the United States in 2006. Although the geometric mean neutralizing antibody titers against the genotype G virus were approximately one-half the titers measured against the vaccine strain, and although titers to both viruses decreased with time after vaccination, antibody induced by immunization with the Jeryl Lynn mumps vaccine strain effectively neutralized the outbreak-associated virus at all time points tested.

Human respiratory syncytial virus surface glycoproteins F, G and SH form an oligomeric complex

Summary.u2002In order to study structural associations, RSV surface glycoproteins were evaluated using heparin agarose affinity chromatography (HAAC). When RSV-infected cell lysate was analyzed by HAAC, all three surface glycoproteins, (F, G and SH), were eluted. Similarly, when separate lysates from Vero cells infected with vaccinia recombinants expressing F (vvF), G (vvG) and SH (vvSH) proteins were subjected to HAAC, only vvF and vvG expressed proteins bound to heparin, whereas vvSH expressed protein did not bind. When lysates from vvF, vvG and vvSH-infected Vero cells were mixed prior to HAAC, only F and G bound heparin. In contrast, following co-infection of Vero cells with vvF, vvG and vvSH, all three proteins were detected subsequent to HAAC. Following HAAC of A2-infected cell lysate and lysate from vvF, vvG and vvSH co-infected Vero cells, two high molecular weight complexes of 175u2009Kd and 210u2009Kd, respectively, were identified that reacted with anti-F, anti-G and anti-SH antisera. In addition, anti-SH antiserum was able to co-precipitate RSV F, G and SH. Using HAAC and a NaCl step gradient we demonstrated that a fraction of RSV F, G and SH eluted at higher salt concentrations than either purified F or G protein. Taken together, these data suggest that RSV F, G and SH glycoproteins can form an oligomeric complex within infected cells and this complex has a higher affinity for heparin than either G or F protein alone.

Immunogenicity, Immunologic Memory, and Safety Following Measles Revaccination in HIV-Infected Children Receiving Highly Active Antiretroviral Therapy

BACKGROUNDnResponse rates and immunologic memory following measles vaccination are reduced in human immunodeficiency virus (HIV)-infected children in the absence of highly active antiretroviral therapy (HAART).nnnMETHODSnHIV-infected children 2 to <19 years old receiving HAART and with HIV loads <30,000 copies/mL, CD4% ≥15, and ≥1 prior measles-mumps-rubella vaccination (MMR) were given another MMR. Measles antibody concentrations before and 8, 32, and 80 weeks postvaccination were determined by plaque reduction neutralization (PRN). A subset was given another MMR 4-5 years later, and PRN antibody was measured before and 7 and 28 days later.nnnRESULTSnAt entry, 52% of 193 subjects were seroprotected (PRN ≥120 mIU/mL). Seroprotection increased to 89% 8 weeks postvaccination, and remained at 80% 80 weeks postvaccination. Of 65 subjects revaccinated 4-5 years later, 85% demonstrated memory based on seroprotection before or 7 days after vaccination. HIV load ≤400 copies/mL at initial study vaccination was associated with higher seroprotection rates, greater antibody concentrations, and memory. Grade 3 fever or fatigue occurred in 2% of subjects.nnnCONCLUSIONSnMeasles revaccination induced high rates of seroprotection and memory in children receiving HAART. Both endpoints were associated with HIV viral load suppression.nnnCLINICAL TRIALS REGISTRATIONnNCT00013871 (www.clinicaltrials.gov).

Persistence of Vaccine-Induced Measles Antibody Beyond Age 12 Months: A Comparison of Response to One and Two Doses of Edmonston-Zagreb Measles Vaccine Among HIV-Infected and Uninfected Children in Malawi

BACKGROUNDnPreviously, we demonstrated that measles antibody prevalence was lower at age 12 months among children infected with human immunodeficiency virus (HIV) than uninfected children following measles vaccination (MV) at ages 6 and 9 months. Among HIV-uninfected children, measles antibody prevalence was lower among 1- than 2-dose MV recipients. Here, we report results through age 24 months.nnnMETHODSnChildren born to HIV-infected mothers received MV at 6 and 9 months, and children of HIV-uninfected mothers were randomized to MV at 6 and 9 months or MV at 9 months. We followed children through age 24 months. The childs HIV status was determined and measles immunoglobulin G (IgG) level was measured by enzyme immunoassay (EIA) and by plaque reduction neutralization (PRN) on a subset.nnnRESULTSnAmong HIV-uninfected children, the difference in measles antibody prevalence at age 12 months between one- and two-dose recipients reported previously by EIA was shown to be smaller by PRN. By age 24 months, 84% and 87% of HIV-uninfected children receiving 1 or 2 doses, respectively, were seroprotected. Only 41% of 22 HIV-infected children were measles seroprotected at age 20 months.nnnDISCUSSIONnMeasles seroprotection persisted through age 24 months among HIV-uninfected children who received 1 or 2 doses of MV. HIV-infected children demonstrated seroprotection through age 12 months, but this was not sustained.

ELISA underestimates measles antibody seroprevalence in US military recruits

The prevalence of antibodies to measles, mumps, and rubella in US military recruits is of importance to public health leaders. We performed ELISA testing using a commercially available product on samples from 537 recruits obtained in 1998, of which 437 were positive (81%). We then performed a validation study in a subsample of the population using plaque reduction neutralization (PRN) to assess misclassification error. This resulted in a corrected estimate of the prevalence of immunity to measles of 96% (95% CI: 92-100%). The military vaccinates a percentage of recruits who are likely to be immune if more sensitive testing, such as PRN, was used.

Measles Virus Neutralizing Antibody Response, Cell-Mediated Immunity, and Immunoglobulin G Antibody Avidity Before and After Receipt of a Third Dose of Measles, Mumps, and Rubella Vaccine in Young Adults

BACKGROUNDnTwo doses of measles, mumps, and rubella (MMR) vaccine are 97% effective against measles, but waning antibody immunity to measles and failure of the 2-dose vaccine occur. We administered a third MMR dose (MMR3) to young adults and assessed immunogenicity over 1 year.nnnMETHODSnMeasles virus (MeV) neutralizing antibody concentrations, cell-mediated immunity (CMI), and immunoglobulin G (IgG) antibody avidity were assessed at baseline and 1 month and 1 year after MMR3 receipt.nnnRESULTSnOf 662 subjects at baseline, 1 (0.2%) was seronegative for MeV-neutralizing antibodies (level, <8 mIU/mL), and 23 (3.5%) had low antibody levels (8-120 mIU/mL). One month after MMR3 receipt, 1 subject (0.2%) was seronegative, and 6 (0.9%) had low neutralizing antibodies, with only 21 of 662 (3.2%) showing a ≥ 4-fold rise in neutralizing antibodies. One year after MMR3 receipt, no subject was seronegative, and 10 of 617 (1.6%) had low neutralizing antibody levels. CMI analyses showed low levels of spot-forming cells after stimulation, suggesting the presence of T-cell memory, but the response was minimal after MMR3 receipt. MeV IgG avidity did not correlate with findings of neutralization analyses.nnnCONCLUSIONSnMost subjects were seropositive before MMR3 receipt, and very few had a secondary immune response after MMR3 receipt. Similarly, CMI and avidity analyses showed minimal qualitative improvements in immune response after MMR3 receipt. We did not find compelling data to support a routine third dose of MMR vaccine.

Supplemental measles vaccine antibody response among HIV-infected and -uninfected children in Malawi after 1- and 2-dose primary measles vaccination schedules.

Background The long-term antibody response to measles vaccine (MV) administered at age 6 months with or without subsequent doses is not well documented. Methods Measles serum antibody responses were evaluated after a supplemental dose of measles vaccine (sMV) administered at a median age of 20 months among Malawian children who had previously received 2 doses of measles vaccine (MV) at ages 6 and 9 months (HIV-infected and random sample of HIV-uninfected) or 1 dose at age 9 months (random sample of HIV-uninfected). We compared measles antibody seropositivity between groups by enzyme linked immunoassay and seroprotection by plaque reduction neutralization geometric mean concentrations. Results Of 1756 children enrolled, 887 (50.5%) received a sMV dose following MV at 9 months of age and had specimens available after sMV receipt, including 401 HIV-uninfected children who received one MV dose at 9 months, 464 HIV-uninfected and 22 HIV-infected children who received two doses of MV at ages 6 and 9 months. Among HIV-uninfected children, protective levels of antibody were found post sMV in 90–99% through ages 24–36 months and were not affected by MV schedule. Geometric mean concentration levels of measles antibody were significantly increased post-sMV among those HIV-uninfected children previously non-responsive to vaccination. Among HIV-infected children, the proportion seroprotected increased initially but by 9 months post-sMV was no higher than pre-sMV. Conclusions Our findings support early 2-dose MV to provide measles immunity for young infants without risk of interference with antibody responses to subsequent MV doses administered as part of SIAs.

1339Measles and Mumps Antibody Response in Young Adults after a Third Dose of Measles-Mumps-Rubella Vaccine

1339. Measles and Mumps Antibody Response in Young Adults after a Third Dose of Measles-Mumps-Rubella Vaccine Amy Parker Fiebelkorn, MSN, MPH; Laura Coleman, PhD, RD; Edward Belongia, MD; Sandra Freeman, CCRC; Daphne York, CCRP; Daoling Bi, MS; Cheryl Zhang, MD* (deceased); Laurie Ngo,; Steven Rubin, PhD; Ashwin Kulkarni,; Susette Audet, BS; Judith Beeler, MD; Division of Viral Diseases, Centers for Disease Control and Prevention, Atlanta, GA; Marshfield Clinic Research Foundation, Marshfield, WI; Abbott Nutrition, Columbus, OH; Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD