Role and plasticity of Th1 and Th17 responses in immunity to Staphylococcus aureus.

The human commensal Staphylococcus aureus (SA) is a leading cause of skin/soft tissue and surgical-site infections, and bacteremia. Functional antibodies and T-cell-mediated immunity, particularly Th1/Th17 responses, are thought to mediate protection. Vaccine development may be hindered by modulation of vaccine-induced T cells by pathogen-activated immunoregulatory responses, e.g., via IL-10.We screened SA proteins for CD4+ T-cell-activating and IL-10/IL-17-inducing capacities using healthy donor-derived PBMCs. Responses were characterized (Th1/Th17/Th22/immunosuppressive IL-10-producing cells) using intracellular cytokine staining and flow cytometry. Phenotypic plasticity of Th1/Th17 cells was evaluated under pro- or anti-inflammatory conditions using modulatory cytokines. The impact of vaccination on SA-specific memory responses was assessed using samples from a clinical trial evaluating AS03-adjuvanted and non-adjuvanted multicomponent (CPS5/CPS8/α-toxin/ClfA) vaccines (NCT01160172).The donors exhibited SA-specific memory T-cell responses, indicative of pre-existing immunity to SA. We identified effective activators of Th1 responses (EbhA/IsaA/SdrE/MntC/Aaa/α-toxin), and Th17 and Th1/Th17 responses (EbhA/IsaA/SdrE and, to a lesser extent, α-toxin), but not of Th22 responses or IL-10 production. MRPII, IsdA, and ClfA were inefficient CD4+ T-cell activators in our assays. IL-10, likely produced by innate immune cells, influenced mainly Th1 cells by suppressing IFN-γ production. The memory CD4+ T-cells observed after long-term stimulation with α-toxin and ClfA indicated that vaccination with these proteins had induced expansion of pre-existing Th1 but not Th17 responses, without apparent adjuvant effect, confirming the trial data. The Th1/Th17-driving proteins (EbhA/IsaA/SdrE) shared low IL-10-promoting abilities and restricted phenotypic plasticity under pro- and anti-inflammatory conditions.Given the complex immunopathology and multiple virulence factors, identification of Th1/Th17-driving antigens, adjuvants and administration routes, and delineation of the role of memory responses, may advance vaccine development.

Long-term immunogenicity and safety after a single dose of the quadrivalent meningococcal serogroups A, C, W, and Y tetanus toxoid conjugate vaccine in adolescents and adults: 5-year follow-up of an open, randomized trial.

BACKGROUND: Long-term protection against meningococcal disease is associated with persistence of post-vaccination antibodies at protective levels. We evaluated the bactericidal antibody persistence and safety of the quadrivalent meningococcal serogroups A, C, W and Y tetanus-toxoid conjugate vaccine (MenACWY-TT) and the meningococcal polysaccharide serogroups A, C, W, and Y vaccine (MenACWY-PS) up to 5 years post-vaccination. METHODS: This phase IIb, open, randomized, controlled study conducted in the Philippines and Saudi Arabia consisted of a vaccination phase and a long-term persistence phase. Healthy adolescents and adults aged 11-55 years were randomized (3:1) to receive a single dose of MenACWY-TT (ACWY-TT group) or MenACWY-PS (Men-PS group). Primary and persistence results up to 3 years post-vaccination have been previously reported. Antibody responses against meningococcal serogroups A, C, W, and Y were assessed by a serum bactericidal antibody assay using rabbit complement (rSBA, cut-off titers 1:8 and 1:128) at Year 4 and Year 5 post-vaccination. Vaccine-related serious adverse events (SAEs) and cases of meningococcal disease were assessed up to Year 5. RESULTS: Of the 500 vaccinated participants, 404 returned for the Year 5 study visit (Total Cohort Year 5). For the Total Cohort Year 5, 71.6-90.0 and 64.9-86.3 % of MenACWY-TT recipients had rSBA titers ≥1:8 and ≥1:128, respectively, compared to 24.8-74.3 and 21.0-68.6 % of MenACWY-PS recipients. The rSBA geometric mean titers (GMTs) remained above the pre-vaccination levels in both treatment groups. Exploratory analyses suggested that both rSBA GMTs as well as the percentages of participants with rSBA titers above the cut-offs were higher in the ACWY-TT than in the Men-PS group for serogroups A, W and Y, with no apparent difference for MenC. No SAEs related to vaccination or cases of meningococcal disease were reported up to Year 5. CONCLUSION: These results suggest that a single dose of MenACWY-TT could protect at least 72 % of vaccinated adolescents and adults against meningococcal disease at least 5 years post-vaccination. TRIAL REGISTRATION: ClinicalTrials.gov NCT00356369.

Safety and immunogenicity of an investigational 4-component Staphylococcus aureus vaccine with or without AS03B adjuvant: Results of a randomized phase I trial.

We assessed the safety, reactogenicity and immunogenicity of a staphylococcal vaccine combining capsular polysaccharides types 5 and 8 (CPS5/8), conjugated to tetanus toxoid (TT), with mutated detoxified α-toxin (AT) and clumping factor A (ClfA). In this phase I, randomized, placebo-controlled, observer-blind trial (NCT01160172), 88 healthy 18- to 40-year-olds received CPS5-TT/CPS8-TT/AT/ClfA vaccine (5/5/10/10 µg or 10/10/30/30 µg dose, each with or without AS03B adjuvant) or saline, at months 0, 1, 6. Solicited and unsolicited adverse events (AEs) were recorded for 7 and 30 d post-vaccination, respectively; potential immune-mediated diseases (pIMDs) and serious AEs (SAEs) were recorded throughout the study. Humoral and antigen-specific CD4(+)/CD8(+) T-cell immunity were assessed from Day (D) 0 to D540 post-vaccination. The most frequently reported solicited local and general AEs were pain (78.6%-100% of subjects), fatigue (36.4%-93.3% of subjects post-dose 1-2) and headache (20%-44.4% of subjects post-dose 3). Overall, 4 SAEs and 2 potential immune-mediated diseases (pIMDs) (none fatal or vaccine-related) were reported. For each antigen, pre-vaccination seropositivity rates were high (85.7%-100%) and geometric mean concentrations (GMCs) in vaccine recipients sharply increased from D0 to D14, then plateaued to study end. Exploratory group comparisons suggested higher GMCs with higher dosage, without AS03B effect. Vaccine-induced antibodies were functional (CPS5 opsonophagocytic assays, and AT/ClfA inhibition assays). AT- and ClfA-specific CD4(+) T-cells with Th0/Th1 cytokine profile were induced at low levels (median <0.05%) by each formulation (intracellular cytokine staining). In conclusion, no safety concerns were identified and each vaccine formulation induced robust humoral immune responses after the first vaccine dose.

Efficacy profile of a bivalent Staphylococcus aureus glycoconjugated vaccine in adults on hemodialysis: Phase III randomized study.

In a previous study in end-stage renal disease (ESRD) hemodialysis patients, a single dose of Staphylococcus aureus type 5 and 8 capsular polysaccharides (T5/T8) conjugated to nontoxic recombinant Pseudomonas aeruginosa exotoxin A investigational vaccine showed no efficacy against S. aureus bacteremia 1 year post-vaccination, but a trend for efficacy was observed over the first 40 weeks post-vaccination. Vaccine efficacy (VE) of 2 vaccine doses was therefore evaluated. In a double-blind trial 3359 ESRD patients were randomized (1:1) to receive vaccine or placebo at week 0 and 35. VE in preventing S. aureus bacteremia was assessed between 3-35 weeks and 3-60 weeks post-dose-1. Anti-T5 and anti-T8 antibodies were measured. Serious adverse events (SAEs) were recorded for 42 days post-vaccination and deaths until study end. No significant difference in the incidence of S. aureus bacteremia was observed between vaccine and placebo groups between weeks 3-35 weeks post-dose 1 (VE -23%, 95%CI: -98;23, p = 0.39) or at 3-60 weeks post-dose-1 (VE -8%, 95%CI: -57;26, p = 0.70). Day 42 geometric mean antibody concentrations were 272.4 µg/ml and 242.0 µg/ml (T5 and T8, respectively) in vaccinees. SAEs were reported by 24%/25.3% of vaccinees/placebo recipients. These data do not show a protective effect of either 1 or 2 vaccine doses against S. aureus bacteremia in ESRD patients. The vaccine induced a robust immune response and had an acceptable safety profile. Further investigation suggested possible suboptimal vaccine quality (manufacturing) and a need to expand the antigen composition of the vaccine. This study is registered at www.clinicaltrials.gov NCT00071214.

Immunogenicity and safety of a booster dose of an investigational adjuvanted polyprotein HIV-1 vaccine in healthy adults and effect of administration of chloroquine.

This phase II study evaluated the effect of chloroquine on the specific CD8(+) T-cell responses to and the safety of a booster dose of investigational human immunodeficiency virus type 1 (HIV-1) F4/AS01(B) vaccine containing 10 µg of recombinant fusion protein (F4) adjuvanted with the AS01(B) adjuvant system. Healthy adults aged 21 to 41 years, primed 3 years before with two F4/AS01(B) doses containing 10 or 30 µg of F4 (ClinicalTrials.gov registration number NCT00434512), were randomized (1:1) to receive the F4/AS01(B) booster administered alone or 2 days after chloroquine (300 mg). F4-specific CD8(+)/CD4(+) T-cell responses were characterized by intracellular cytokine staining and lymphoproliferation assays and anti-F4 antibodies by enzyme-linked immunosorbent assays (ELISAs). No effect of chloroquine on CD4(+)/CD8(+) T-cell and antibody responses and no vaccine effect on CD8(+) T-cell responses (cytokine secretion or proliferation) were detected following F4/AS01(B) booster administration. In vitro, chloroquine had a direct inhibitory effect on AS01(B) adjuvant properties; AS01-induced cytokine production decreased upon coincubation of cells with chloroquine. In the pooled group of participants primed with F4/AS01(B) containing 10 µg of F4, CD4(+) T-cell and antibody responses induced by primary vaccination persisted for at least 3 years. The F4/AS01(B) booster induced strong F4-specific CD4(+) T-cell responses, which persisted for at least 6 months with similar frequencies and polyfunctional phenotypes as following primary vaccination, and high anti-F4 antibody concentrations, reaching higher levels than those following primary vaccination. The F4/AS01(B) booster had a clinically acceptable safety and reactogenicity profile. An F4/AS01(B) booster dose, administered alone or after chloroquine, induced robust antibody and F4-specific CD4(+) T-cell responses but no significant CD8(+) T-cell responses (cytokine secretion or proliferation) in healthy adults. (This study has been registered at ClinicalTrials.gov under registration number NCT00972725).

Safety, immunogenicity, and antibody persistence following an investigational Streptococcus pneumoniae and Haemophilus influenzae triple-protein vaccine in a phase 1 randomized controlled study in healthy adults.

We investigated a protein-based nontypeable Haemophilus influenzae (NTHi) and pneumococcal (HiP) vaccine containing pneumococcal histidine triad D (PhtD), detoxified pneumolysin (dPly), and NTHi protein D (PD) in adults. In a phase I study, 40 healthy 18- to 40-year-old subjects were randomized (2:2:1) to receive two HiP doses administered 60 days apart, with or without AS03 adjuvant (HiP-AS and HiP groups, respectively), or Engerix B (GlaxoSmithKline, Belgium) as a control. Safety, antibodies, and antigen-specific CD4(+) T-cell immune responses were assessed before and until 480 days after vaccination. No serious adverse events were reported, and no subject withdrew due to an adverse event. Local and systemic symptoms were reported more frequently in the HiP-AS group than in the other two groups. The frequency and intensity of local and systemic symptoms appeared to increase after the second dose of HiP-AS or HiP but not Engerix B. Antibody geometric mean concentrations (GMCs) for PhtD, dPly, and PD increased after each dose of HiP-AS or HiP, with higher GMCs being observed in the HiP-AS group (statistically significant for anti-PD after dose 1 and anti-Ply after dose 2). GMCs remained higher at day 420 than prior to vaccination in both the HiP-AS and HiP groups. Antigen-specific CD4(+) T cells increased after each dose but were unmeasurable by day 480. Two doses of an investigational PhtD-dPly-PD protein vaccine induced humoral immunity and antigen-specific CD4(+) T-cell responses after each dose, with generally higher responses when the vaccine was administered with AS03. HiP combined with AS03 appeared to be more reactogenic than the antigens alone. (This study has been registered at ClinicalTrials.gov under registration no. NCT00814489.).

Immune response, antibody persistence, and safety of a single dose of the quadrivalent meningococcal serogroups A, C, W-135, and Y tetanus toxoid conjugate vaccine in adolescents and adults: results of an open, randomised, controlled study.

BACKGROUND: The best strategy to protect individuals against meningococcal disease is to immunize against multiple serogroups. Immunogenicity, antibody persistence, and safety of the EU-licensed meningococcal ACWY-tetanus toxoid conjugate vaccine (MenACWY-TT) were evaluated in healthy participants aged 11-55 years from the Philippines and Saudi Arabia. METHODS: In this phase IIb, open, controlled study, 500 participants were randomised (3:1) to receive one dose of MenACWY-TT or a licensed meningococcal polysaccharide vaccine (Men-PS). Functional antibody responses against meningococcal serogroups A, C, W-135, and Y were assessed by a serum bactericidal antibody assay using rabbit complement (rSBA) at Month 0, Month 1, Year 1, Year 2, and Year 3. Vaccine response was defined as an rSBA titre ≥32 at Month 1 in participants who were seronegative (rSBA titre <8) pre-vaccination and as at least a four-fold increase in titre in participants who were seropositive pre-vaccination. Solicited symptoms were recorded up to Day 4, safety outcomes up to Month 6, and serious adverse events related to vaccination up to Year 3. RESULTS: Pre-specified criteria for non-inferiority of MenACWY-TT versus Men-PS were met in terms of rSBA vaccine response and incidence of grade 3 general symptoms. At Month 1, 82.7%-96.3% of MenACWY-TT and 69.7%-91.7% in Men-PS recipients had a vaccine response for each serogroup. At Year 3, ≥99.1% and ≥92.9% of MenACWY-TT recipients retained rSBA titres ≥8 and ≥128, respectively, as compared to ≥86.7% and ≥80.0% in the Men-PS group. Both vaccines had a clinically acceptable safety profile, although injection site redness and swelling were more frequent in MenACWY-TT recipients. CONCLUSIONS: These results suggest that MenACWY-TT could protect adolescents and adults against meningococcal disease up to three years post-vaccination. TRIAL REGISTRATION: This study is registered at http://www.clinicaltrials.gov/NCT00356369.

A combined Haemophilus influenzae type B Neisseria meningitidis serogroup C tetanus toxoid conjugate vaccine is immunogenic and well-tolerated when coadministered with diphtheria, tetanus, acellular pertussis hepatitis B-inactivated poliovirus at 3, 5 and 11 months of age: results of an open, randomized, controlled study.

BACKGROUND: This study evaluated the immunogenicity, reactogenicity and safety of the combined Haemophilus influenzae type B Neisseria meningitidis serogroup C tetanus toxoid conjugate vaccine (Hib-MenC-TT) coadministered with diphtheria, tetanus, acellular pertussis hepatitis B-inactivated poliovirus (DTPa-HBV-IPV) as 2 primary and 1 booster doses at 3, 5 and 11 months of age. METHODS: In this phase III open study (NCT00327184), 709 infants were randomized in 2 parallel groups (1:1) to receive either Hib-MenC-TT coadministered with DTPa-HBV-IPV or control vaccines (MenC-TT coadministered with DTPa-HBV-IPV/Hib). Serum bactericidal activity for MenC (rSBA-MenC) and antibody concentrations against polyribosylribitol phosphate from Hib (anti-PRP) and hepatitis B (anti-HBs) were measured at 1 month after dose 2, before booster and 1 month after booster dose. Solicited (local/general) and unsolicited symptoms were assessed up to 4 and 31 days, respectively, after each vaccination. Serious adverse events were recorded throughout the study. RESULTS: One month after dose 2, high percentages of infants in both groups had rSBA-MenC titers ≥ 8 (≥ 99.1%), anti-PRP concentrations ≥ 0.15 µg/mL (≥ 96.5%) and anti-HBs concentrations ≥ 10 mIU/mL (≥ 95.3%), which persisted up to the booster vaccination (≥ 94.5%, ≥ 86.1%, ≥ 94.2%) and increased again after the booster dose (100%, 100%, ≥ 99%). Exploratory analyses indicated that rSBA-MenC geometric mean titers were lower and anti-PRP geometric mean concentrations were higher in the infants vaccinated with Hib-MenC-TT compared with the control vaccines at all time points. The safety profiles of the coadministered vaccines were similar in both groups. CONCLUSIONS: The Hib-MenC-TT and DTPa-HBV-IPV vaccines are immunogenic with a clinically acceptable safety profile when coadministered as 2 primary doses during infancy and 1 booster dose at 11 months of age.

Randomized trial to assess the immunogenicity, safety and antibody persistence up to three years after a single dose of a tetravalent meningococcal serogroups A, C, W-135 and Y tetanus toxoid conjugate vaccine in toddlers.

Effective vaccines offering broad protection to toddlers, who are at high risk for invasive meningococcal disease, are needed. Here, the immunogenicity, safety and antibody persistence of the tetravalent meningococcal ACWY tetanus toxoid conjugate vaccine (MenACWY-TT) were evaluated in toddlers. Healthy participants aged 12 to 23 mo (n = 304) were randomized (3:1) to receive one dose of MenACWY-TT or a monovalent meningococcal serogroup C conjugate vaccine (MenC-CRM 197). Serum bactericidal activity was evaluated with assays using rabbit (rSBA) and human (hSBA) complement up to three years post-vaccination. MenACWY-TT was demonstrated to be non-inferior to MenC-CRM 197 in terms of immunogenicity to serogroup C, and the pre-specified immunogenicity criteria for serogroups A, W-135 and Y were met. Exploratory analyses suggested that rSBA geometric mean titers (GMTs), hSBA GMTs and proportions of toddlers with rSBA titers ≥ 1:128 and hSBA titers ≥ 1:4 and ≥ 1:8 were higher for all serogroups at one month post-vaccination with MenACWY-TT compared with MenC-CRM 197. At three years post-vaccination, at least 90.8% and 73.6% of MenACWY-TT recipients retained rSBA titers ≥ 1:8 for all serogroups and hSBA titers ≥ 1:4 for serogroups C, W-135 and Y, respectively, but the percentages of toddlers with hSBA titers ≥ 1:4 for serogroup A decreased to 21.8%. In both groups, grade 3 adverse events were infrequently reported and no serious adverse events were considered causally related to vaccination. These results suggest that one single dose of MenACWY-TT induces a robust and persistent immune response and has an acceptable safety profile in toddlers.

A randomized study to assess the immunogenicity, antibody persistence and safety of a tetravalent meningococcal serogroups A, C, W-135 and Y tetanus toxoid conjugate vaccine in children aged 2-10 years.

Incidence of meningococcal diseases is high in children, and effective vaccines are needed for this age group. In this phase II, open, controlled study, 309 children aged 2-10 y from Finland were randomized (3:1) into two parallel groups to receive one dose of meningococcal ACWY-tetanus toxoid conjugate vaccine (ACWY-TT group; n = 231) or a licensed meningococcal ACWY polysaccharide vaccine (Men-PS group; n = 78). Serum bactericidal activity using rabbit complement (rSBA) was evaluated up to three years post-vaccination. Exploratory comparisons suggested that rSBA vaccine response rates and geometric mean titers (GMTs) for each serogroup at one month post-vaccination and rSBA GMTs for serogroups A, W-135 and Y up to three years post-vaccination were higher in the ACWY-TT compared with Men-PS group, but did not detect any difference between groups in terms of rSBA-MenC GMTs at three years post-vaccination; this is explained by the higher proportion of children from the Men-PS group who were excluded because they were re-vaccinated with a monovalent meningococcal serogroup C vaccine due to loss of protective antibody levels against this serogroup. Although there was a higher incidence of local reactogenicity in the ACWY-TT group, general and unsolicited symptoms reporting rates were comparable in both groups. This study showed that MenACWY-TT was immunogenic with a clinically acceptable safety profile in children aged 2-10 y. MenACWY-TT induced higher functional antibody titers for all serogroups, which persisted longer for serogroups A, W-135 and Y, than the MenACWY polysaccharide vaccine.

Five-year antibody persistence and safety following a booster dose of combined Haemophilus influenzae type b-Neisseria meningitidis serogroup C-tetanus toxoid conjugate vaccine.

BACKGROUND: Booster vaccination with the combined Haemophilus influenza type b-Neisseria meningitides serogroup C-tetanus toxoid vaccine (Hib-MenC-TT) has been reported to induce different MenC antibody responses depending on the priming vaccines, with a possible impact on long-term protection. Here, the five-year persistence of immune responses induced by a booster dose of Hib-MenC-TT was evaluated in toddlers primed with either Hib-MenC-TT or MenC-TT. METHODS: This is the follow-up of a phase III, open, randomized study, in which a Hib-MenC-TT booster dose was given at 13.14 months of age to toddlers primed with either 3 doses of Hib-MenC-TT or 2 doses of MenC-TT in infancy. Children in the control group had received 3 primary doses and a booster dose of MenC-CRM197. Functional antibodies against MenC were measured by a serum bactericidal assay with rabbit complement (rSBA-MenC) and antibodies against Hib polyribosylribitol phosphate by enzyme-linked immunosorbent assay. Serious adverse events considered by the investigator to be possibly related to vaccination were to be reported throughout the study. RESULTS: At 66 months postbooster, rSBA-MenC titers ≥8 were retained by 82.6% of children primed with Hib-MenC-TT, 94.1% of children primed with MenC-TT, and 60.9% of children in the control group. All children who received the Hib-MenC-TT booster dose retained anti- polyribosylribitol phosphate concentrations ≥0.15 µg/mL. No serious adverse events considered possibly related to vaccination were reported. CONCLUSIONS: There is evidence of good antibody persistence against MenC and Hib for more than five years postbooster vaccination with Hib-MenC TT in toddlers primed with Hib-MenC-TT or MenC-TT.

The tetravalent meningococcal serogroups A, C, W-135, and Y tetanus toxoid conjugate vaccine is immunogenic with a clinically acceptable safety profile in subjects previously vaccinated with a tetravalent polysaccharide vaccine.

OBJECTIVES: The immunogenicity and safety of the tetravalent meningococcal serogroups A, C, W-135, and Y tetanus toxoid conjugate vaccine (MenACWY-TT) were evaluated in subjects previously vaccinated with a tetravalent meningococcal polysaccharide vaccine and in subjects without previous meningococcal vaccination. METHODS: In this phase II, open, controlled study (NCT00661557), healthy subjects aged 4.5-34 years received one dose of MenACWY-TT at month 0. Subjects in the MPS group (n=192) had received polysaccharide vaccine in a study conducted 30-42 months earlier; age-matched subjects in the noMPS control group (n=79) had received no meningococcal vaccination within the past 10 years. Serum bactericidal activity using rabbit complement (rSBA) was measured at month 0 and month 1. RESULTS: At month 1, ≥97.0% of subjects had rSBA titers ≥1:128. Post-vaccination rSBA geometric mean titers (GMTs) were ≥3.9-fold higher than pre-vaccination in both treatment groups. Exploratory analyses showed no statistically significant differences between groups in percentages of subjects with rSBA titers ≥1:8 and ≥1:128, but significantly lower rSBA GMTs and vaccine response rates for each serogroup in the MPS versus the noMPS group. MenACWY-TT had an acceptable safety profile in both groups. CONCLUSIONS: These results suggest that MenACWY-TT could be used in vaccination programs irrespective of the pre-vaccination status with polysaccharide vaccine.

Antibody persistence and immune memory 15 months after priming with an investigational tetravalent meningococcal tetanus toxoid conjugate vaccine (MenACWY-TT) in toddlers and young children.

The present extension study, conducted in children originally vaccinated at 12-14 mo or 3-5 y of age, assessed antibody persistence and immune memory induced by an investigational tetravalent meningococcal serogroups A, C, W-135 and Y tetanus toxoid conjugate vaccine (MenACWY-TT). In the original study, participants were randomized to receive one dose of MenACWY-TT or licensed age-appropriate meningococcal control vaccines. Fifteen months post-vaccination, all participants underwent serum sampling to evaluate antibody persistence and participants previously vaccinated as toddlers received a polysaccharide challenge to assess immune memory development. Exploratory comparisons showed that (1) All children and ≥ 92.3% of the toddlers maintained serum bactericidal (rSBA) titers ≥ 1:8 at 15 mo post MenACWY-TT vaccination; statistically significantly higher rSBA geometric mean titers (GMTs) were observed compared with control vaccines. (2) At one month after polysaccharide challenge, all toddlers primed with MenACWY-TT or with the monovalent serogroup C conjugate vaccine had rSBA titers ≥ 1:8 and ≥ 1:128 for serogroup C and similar rSBA-GMTs; rSBA-GMTs for serogroups A, W-135 and Y were statistically significantly higher in toddlers primed with MenACWY-TT compared with the control vaccine. Thus, a single dose of MenACWY-TT induced persisting antibodies in toddlers and children and immune memory in toddlers. This study has been registered at www.clinicaltrials.gov NCT00126984.

Immunogenicity and safety of H influenzae type b-N meningitidis C/Y conjugate vaccine in infants.

BACKGROUND: Meningococcal disease incidence is highest in children younger than 2 years of age, yet there is no US-licensed vaccine for this age group. A phase III study evaluated the immunogenicity and safety of an investigational Haemophilus influenzae type b (Hib)-Neisseria meningitidis serogroups C and Y-tetanus toxoid conjugate vaccine (HibMenCY). MATERIALS AND METHODS: A total of 4180 infants were randomly assigned to receive the HibMenCY at the ages of 2, 4, 6, and 12 to 15 months or the licensed Hib tetanus toxoid conjugate vaccine (ActHIB) at 2, 4, and 6 months and Hib conjugated to N meningitidis outer membrane protein (PedvaxHIB) at 12 to 15 months. Routinely scheduled vaccines were coadministered. Serum bactericidal activity using human complement and anti-polyribosylribitol phosphate antibodies were assessed in 991 subjects. Local and systemic adverse reactions were recorded for 4 days after each dose. RESULTS: The percentage of HibMenCY recipients with serum bactericidal assay using human complement titers of 1:8 or higher after dose 3 was 98.8% for N meningitidis serogroup C (MenC) and 95.8% for N meningitidis serogroup Y (MenY). After dose 4, the percentages were 98.5% and 98.8%, respectively. The percentage of HibMenCY recipients with postdose 3 anti-polyribosylribitol phosphate antibody levels of ≥ 1.0 µg/mL was noninferior to that of control (96.3% vs 91.2%). After dose 4, MenC and MenY serum bactericidal assay using human complement antibody titers increased 12-fold over pre-dose 4 levels. Incidence of pain, redness, and swelling at the HibMenCY injection sites tended to be lower than with Hib type b after the first 3 doses and after the fourth dose. Rates of systemic symptoms were similar across groups. CONCLUSIONS: The HibMenCY was immunogenic against MenC and MenY and induced anti-polyribosylribitol phosphate antibody levels noninferior to those of licensed Hib conjugate vaccine. The safety profile of the HibMenCY was clinically acceptable and comparable to Hib conjugate vaccine.

Measurement of functional anti-meningococcal serogroup a activity using strain 3125 as the target strain for serum bactericidal assay.

Functional anti-N. meningitidis serogroup A (MenA) activity in human serum is detected by serum bactericidal assay (SBA), using either rabbit (rSBA) or human (hSBA) complement, with F8238 as the recommended MenA SBA target strain. However, the F8238 strain may not be optimal for this purpose because, as we show here, it expresses the L11 immunotype, whereas most MenA invasive strains express the L(3,7)9 or L10 immunotype. Moreover, SBA results may be strain dependent, because immunotypes differ in their sensitivity to complement, emphasizing the need to choose the most appropriate strain. Sera from random subsets of infants, toddlers, children, and adolescents in clinical trials of MenA conjugate vaccines were tested by rSBA using strains 3125 (L10) and F8238 (L11). In unvaccinated subjects from all age groups, the percentages of seropositive samples (rSBA-MenA titer, ≥1:8) was lower using strain 3125 than using strain F8238. However, in toddlers and adolescents immunized with a conjugate MenA vaccine, the percentages of seropositive samples generally were similar using either strain in the rSBA. In two studies, sera also were tested with hSBA. Using hSBA, the differences in the percentages of seroprotective samples (hSBA-MenA titer, ≥1:4) between strains 3125 and F8238 was less apparent, and in contrast with rSBA, the percentage of seroprotective samples from unvaccinated subjects was slightly higher using strain 3125 than using strain F8238. In adults vaccinated with plain MenA polysaccharide, the percentage of seroprotective samples was higher using strain 3125 than with strain F8238, and the vaccine response rates using strain 3125 were better aligned with the demonstrated efficacy of MenA vaccination. In conclusion, SBA results obtained using the MenA L10 3125 strain better reflected vaccine-induced immunity.

Immediate and longer term immunogenicity of a single dose of the combined haemophilus influenzae type B-Neisseria meningitidis serogroup C-tetanus toxoid conjugate vaccine in primed toddlers 12 to 18 months of age.

Hib-primed but MenC-naive toddlers (N = 433) were randomized to receive 1 dose of Hib-MenC-TT or separate Hib-TT and MenC-CRM197 vaccines. One month later, noninferiority was demonstrated for serum bactericidal anti-MenC antibodies (rSBA) and Hib antipolyribosylribitol phosphate (PRP) antibodies; >99% in both groups had rSBA titer ≥ 8 or anti-PRP concentration ≥ 0.15 µg/mL. After 12 months, rSBA titer ≥ 8 persisted in 86.7% and 76.4%, and anti-PRP concentration ≥ 0.15 µg/mL persisted in 98.8% and 100% of children, respectively.

Immunogenicity and safety of an investigational combined haemophilus influenzae type B-Neisseria meningitidis serogroups C and Y-tetanus toxoid conjugate vaccine.

BACKGROUND: Neisseria meningitidis serogroups B, C, and Y cause most meningococcal disease in industrialized countries. A Haemophilus influenzae type b-meningococcal serogroups C and Y-tetanus toxoid conjugate vaccine (HibMenCY-TT) was evaluated. METHODS: A total of 1104 infants (randomized 3:1:1) were vaccinated at 2, 4, and 6 months with HibMenCY-TT, MenC-CRM197 + Hib-TT, or Hib-TT. At 12 to 15 months, HibMenCY-TT and MenC-CRM-primed children received HibMenCY-TT; Hib-TT-primed received N. meningitidis serogroup B Hib-outer membrane protein complex. Antibody concentrations and rabbit/human complement serum bactericidal antibody titers (rSBA/hSBA) were determined. Safety was monitored after each dose (diary cards for first 31 days) until 6 months postdose 4. RESULTS: Postdose 3, rates of antipolyribosylribitol phosphate ≥ 1 µg/mL and rSBA-MenC ≥1:128 in HibMenCY-TT recipients were noninferior to licensed controls. Percentages reaching 0.15 µg/mL (1.0 µg/mL postdose 3) and antipolyribosylribitol phosphate GMC were significantly higher after HibMenCY-TT than Hib-TT postdose 2 and postdose 3. The GMC remained significantly higher before and after dose 4. Proportions of HibMenCY-TT recipients with rSBA ≥ 1:8 were 95.6% (MenC), 98.6% (MenY) postdose-2, ≥ 99% for MenC/Y postdose 3 and 4; hSBA ≥ 1:4 were 95.5% (MenC), 89.8% (MenY) postdose 2, >97% for MenC/Y postdose 3 and 4. HibMenCY-TT had a similar safety profile to control vaccines. CONCLUSIONS: HibMenCY-TT induced noninferior Hib and MenC responses compared with monovalent Hib and MenC conjugates with a comparable safety profile. Bactericidal antibodies against MenC/Y were induced after 2 doses of HibMenCY-TT.

Persistence of immunity following a booster dose of Haemophilus influenzae type B-Meningococcal serogroup C glycoconjugate vaccine: follow-up of a randomized controlled trial.

BACKGROUND: Antibodies against Haemophilus influenzae type b (Hib) and serogroup C Neisseria meningitidis (MenC) wane after early infant immunization. METHODS: Children previously immunized in a randomized controlled trial at ages 2, 3, and 4 months with DTPa-IPV-Hib and MenC-CRM197 (MenC-CRM group) or DTPa-IPV and Hib-MenC-TT (Hib-MenC-TT group) had blood samples drawn at 1 and 2 years following a booster dose of Hib-MenC-TT at 12 to 15 months of age. A blood sample was also drawn at the year 2 follow-up from a separately recruited age-matched control group who had not received a booster. RESULTS: In 271 children at year 1, mean 14.6 months (range: 12-18 months) following the Hib-MenC-TT booster, MenC bactericidal titers above the protective threshold (rSBA ≥ 1:8) was demonstrated in 89.0% of the Hib-MenC-TT group and 69.5% of MenC-CRM participants. Antipolyribosylribitol phosphate Ig ≥ 1.0 µg/mL (Hib correlate for long-term protection) was seen in 94.9% and 82.5%, respectively.In 379 participants (including 72 control children) at year 2 (age: 39-43 months, 25-31 months post Hib-MenC-TT) persistence of MenC antibodies was demonstrated in 67.1% of the Hib-MenC-TT group and 40.5% of the MenC-CRM group, compared with 44.1% of control group participants. Antipolyribosylribitol phosphate Ig ≥ 1.0 µg/mL was seen in 89.0%, 74.7%, and 38.9%, respectively. CONCLUSIONS: A toddler Hib-MenC-TT booster helps sustain immunity against Hib to 3½ years of age. Persistence of MenC antibody is similar in children primed with MenC-CRM197 in infancy who receive a booster Hib-MenC-TT, to those who receive no booster. Persistence of MenC antibody is better when primed and boosted with Hib-MenC-TT.

Combined Haemophilus influenzae type b and Neisseria meningitidis serogroup C (HibMenC) or serogroup C and Y-tetanus toxoid conjugate (and HibMenCY) vaccines are well-tolerated and immunogenic when administered according to the 2,3,4 months schedule with a fourth dose at 12-18 months of age.

Combined HibMenCY and HibMenC conjugate vaccines may facilitate inclusion of vaccination against MenC and MenY into routine vaccination schedules, without additional injections. Immunogenicity and reactogenicity of vaccination with three different formulations of a novel HibMenCY-conjugate vaccine, or a HibMenC-conjugate vaccine was assessed. Infants were randomized to receive either Hib(2.5 µg)-MenC(5 µg)-MenY(5 µg)-TT, Hib(5 µg)-MenC(10 µg)-MenY(10 µg)-TT, Hib(5 µg)-MenC(5 µg)-MenY(5 µg)-TT or Hib(5 µg)-MenC(5 µg)-TT vaccines co-administered with DTPa-HBV-IPV at 2-3-4 months of age. Controls received licensed conjugate MenC-CRM197 vaccine co-administered with DTPa-HBV-IPV/Hib. A fourth dose was administered to a subset of children at age 12-18 months. Anti-PRP concentrations and meningococcal bactericidal (rSBA-MenC/Y) titres were measured prior to and one month post third and fourth vaccination dose. Solicited local, general symptoms and unsolicited adverse events were recorded for 7 and 30 days after each vaccination, respectively. Post dose 3, all subjects had anti-PRP antibody levels ≥ 0.15 µg/ml and rSBA-MenC ≥ 1:8. 97.0%-98.6% of HibMenCY recipients had rSBA-MenY ≥ 1:8. Pre-dose-4, 95.6%-100% of HibMenCY and HibMenC recipients had anti-PRP ≥ 0.15 µg/ml and 90.7%-97.6% recipients had rSBA-MenC titres ≥ 1:8. In HibMenCY groups, 78.6%-86.7% had persisting rSBA-MenY ≥ 1:8. The post-dose-4 response was robust after all vaccines with all subjects having anti-PRP ≥ 1 µg/ml and 92.3%-100% rSBA-MenC ≥ 1:128. All HibMenCY recipients had rSBA-MenY ≥ 1:128. Vaccination with the novel Hib-meningococcal vaccines had a safety profile similar to control. HibMenCY and HibMenC conjugate vaccine formulations given at 2-3-4 months of age with a fourth dose in the second year of life were immunogenic and had a comparable safety profile to licensed vaccines. (study 792014 and 100381;www.clinicaltrial.govID:NCT00129116)

Three doses of an experimental detoxified L3-derived lipooligosaccharide meningococcal vaccine offer good safety but low immunogenicity in healthy young adults.

This open, randomized phase I study evaluated the safety and reactogenicity of an experimental meningococcal serogroup B (MenB) vaccine obtained from outer membrane vesicle detoxified L3-derived lipooligosaccharide. Healthy young adults (n = 150) were randomized to receive either experimental vaccine (provided in five formulations, n = 25 in each group) or VA-Mengoc-BC (control, n = 25) administered on a 0- to 6-week/6-month schedule. Serum bactericidal assays performed against three MenB wild-type strains assessed the immune response, defined as a 4-fold increase from pre- to postvaccination. No serious adverse events related to vaccination were reported. Pain at the injection site, fatigue, and headache were the most commonly reported adverse events. Solicited adverse events graded level 3 (i.e., preventing daily activity) were pain (up to 17% of the test subjects versus 32% of the controls), fatigue (up to 12% of the test subjects versus 8% of the controls), and headache (up to 4% of any group). Swelling graded level 3 (greater than 50 mm) occurred in up to 4% of the test subjects versus 8% of the controls. The immune responses ranged from 5% to 36% across experimental vaccines for the L3 H44-76 strain (versus 27% for the control), from 0% to 11% for the L3 NZ98/124 strain (versus 23% for the control), and from 0% to 13% for the L2 760676 strain (versus 59% for the control). All geometric mean titers were below those measured with the control vaccine. The five experimental formulations were safe and well tolerated but tended to be less immunogenic than the control vaccine.