Don Roberton

A cross-sectional survey to assess community attitudes to introduction of Human Papillomavirus vaccine

Objective: A vaccine to prevent human papilloma virus (HPV) infection has been licensed recently in the United States of America and Australia. The aim of this study was to assess community attitudes to the introduction of HPV vaccine in the State of South Australia.

Acellular Pertussis Vaccine at Birth and One Month Induces Antibody Responses By Two Months of Age

Background: Infants less than 3 months of age are at highest risk of hospitalization and death from pertussis. Several studies have examined antibody responses to pertussis vaccines at birth but no previous study has evaluated 2 doses of monovalent acellular pertussis vaccine (aPV) before 2 months of age. Methods: Seventy-six newborns were randomized at birth to 3 groups–aPV at birth and 1 month, aPV at birth, and control. All infants received hepatitis B vaccine (HBV) at birth followed at 2, 4, and 6 months by a combination vaccine including aPV, diphtheria, tetanus, Haemophilus influenzae type b (Hib), hepatitis B, polio antigens and 7 valent conjugate pneumococcal vaccine. IgG antibody responses to pertussis toxoid (PT), filamentous hemagglutinin (FHA), and pertactin (PRN) were measured in maternal serum and in infants at 2, 4, 6, and 8 months of age. Antibody responses to hepatitis B, diphtheria, tetanus, and Hib were measured at 8 months only. A parental diary and active telephone follow-up occurred for 7 days after each vaccination. Results: The aPV birth dose was well tolerated. By 2 months of age, 22 of 25 (88%) of 2 dose recipients had detectable IgG antibody to PT (IgG PT) compared with 9 of 21 (43%) who received a birth dose only and 3 of 20 (15%) of controls. Infants in the 2 dose group had a geometric mean concentration (GMC) of IgG PT of 16 ELISA units per mL (EU/mL), 95% CI: 11 to 25, significantly higher than birth dose only (5 EU/mL, 95% CI: 3–8) and controls (3 EU/mL, 95% CI: 2–5). At 8 months of age, following 5, 4, and 3 doses of aP-containing vaccine, respectively, IgG PT had plateaued but IgG to FHA and PRN increased with successive doses. There was a trend to lower antibody responses for hepatitis B and Hib with higher numbers of Pa doses. Conclusion: These data suggest that aPV at birth and 1 month induces significantly higher IgG antibody against pertussis antigens by 2 months of age without reducing subsequent pertussis antibody responses. Larger and more detailed studies of aPV from birth are needed to evaluate other antibody responses and the potential of this approach to reduce death and morbidity from Bordetella pertussis infection in the first 3 months of life.

Isolation of antigen-specific B cells

Cell separation techniques are important in immunology. Major cell populations can be separated successfully with high purity. However, isolation of cells which are specific for particular antigens is more challenging because of the relatively small numbers of antigen‐specific cells, and the lack of independent markers available to determine the purity of the isolated population. In this review, the literature describing three principal techniques used to separate antigen‐specific cells has been reviewed. Particular emphasis has been placed on yield and purity; the two most important parameters of any purification method. The most promising isolation methods have used immunomagnetic sorting and multiparametric flow cytometric analysis.

Expression of Cytokine Receptors by Human Cord Blood Lymphocytes: Comparison with Adult Blood Lymphocytes

ABSTRACT: The expression of receptors for several cytokines (IL 2, IL-4, IL-6, IL-7, tumor necrosis factor, and interferon-γ) was examined in human cord blood cells in comparison with adult blood cells. A previously described high sensitivity immunofluorescence procedure was used to render the low levels of receptor measurable. Cord blood lymphocytes expressed measurable levels of most cytokine receptors, but expression tended to be lower than in adult blood cells. Examination of different lymphocyte subpopulations revealed a complex pattern with some cell types expressing particular receptors equivalent to adult levels. Cord and adult blood monocytes expressed similar cytokine receptor profiles. Receptor expression in cord lymphocytes could be regulated by activation. The results provide indications as to the relative activities of different cytokines in the development of the immune system in the neonate.

Reactogenicity and immunogenicity of a live attenuated tetravalent measles-mumps-rubella-varicella (MMRV) vaccine

In countries where routine varicella vaccination is implemented, it is usually given at the same age as that recommended for measles-mumps-rubella (MMR) vaccination. A combined multivalent measles-mumps-rubella-varicella (MMRV) vaccine would offer the convenience of a single injection and facilitate implementation of varicella vaccination into routine childhood immunisation schedules. We evaluated the immunogenicity and reactogenicity of a tetravalent MMRV candidate vaccine compared to an extemporaneous mix of a measles-mumps-rubella vaccine and varicella vaccine (MMR/V), and to a measles-mumps-rubella (MMR) vaccine alone. A multicentre study was conducted in which a total of 240 healthy children aged 12 months (80 per group) were randomised to receive MMRV, MMR/V, or MMR alone. Active surveillance for adverse events was undertaken for 43 days post-vaccination. Blood samples were taken prior to vaccination and at 60 days post-vaccination. There were no significant differences between groups in rates of pain, redness, or swelling at the site of vaccination. There was no significant difference in the rate of any fever (axillary temperature >or=37.5 degrees C) and grade 3 fever (axillary temperature >39.0 degrees C) between the groups receiving MMRV and MMR during the 43-day follow-up period. Although, a significant increase was found for fever of any cause with onset between days 0 and 14 for MMRV compared to the MMR group, there was no significant difference in grade 3 fever rates during the same period. With respect to immunogenicity, MMRV and MMR/V demonstrated similar seroconversion rates to each component compared to MMR alone, with at least 91.9% of subjects in all groups seroconverting to each vaccine component 60 days after vaccination. Decreased GMTs for varicella antibody at day 60 indicated that there may have been inhibition of this response compared to MMR/V. This tetravalent MMRV candidate vaccine showed promising results, although further examination of the possible increase in minor fever and decreased varicella immunogenicity should be assessed in future studies.

Evaluation of Combined Live, Attenuated Respiratory Syncytial Virus and Parainfluenza 3 Virus Vaccines in Infants and Young Children

We evaluated a combination respiratory syncytial virus (RSV) and parainfluenza 3 virus (PIV3) live, attenuated intranasal vaccine for safety, viral replication, and immunogenicity in doubly seronegative children 6-18 months old. RSV cpts-248/404 and PIV3-cp45 vaccines were combined in a dose of 10(5) plaque-forming units of each per 0.5-mL dose and compared with monovalent vaccines or placebo. The virus shedding pattern of RSV was not different between monovalent RSV cpts-248/404 vaccine and combination vaccine. Modest reductions in the shedding of PIV3-cp45 vaccine virus were found after the administration of RSV cpts-248/404 and PIV3-cp45 vaccine, relative to monovalent PIV3 vaccine; 16 (76%) of 21 children given combination vaccine shed PIV3-cp45 versus 11 (92%) of 12 of those given monovalent PIV3 vaccine. Both vaccines were immunogenic, and antibody responses were similar between the monovalent groups and the combination group. Combined RSV/PV3 vaccine is feasible for simultaneous administration, and further studies are warranted.

A bivalent Neisseria meningitidis recombinant lipidated factor H binding protein vaccine in young adults: results of a randomised, controlled, dose-escalation phase 1 trial.

Neisseria meningitidis is a leading cause of meningitis and septicaemia, but a broadly-protective vaccine against endemic serogroup B disease is not licensed and available. The conserved, outer-membrane lipoprotein factor H binding protein (fHBP, also known as LP2086) is expressed as one of two subfamily variants in virtually all meningococci. This study investigated the safety, tolerability, and immunogenicity of a recombinant-expressed bivalent fHBP (r-fHBP) vaccine in healthy adults. Participants (N=103) aged 18-25 years were recruited into three ascending dose level cohorts of 20, 60, and 200μg of a bivalent r-fHBP vaccine formulation and randomised to receive vaccine or placebo at 0, 1, and 6 months. The vaccine was well tolerated. Geometric mean titres (GMTs) for r-fHBP subfamily-specific IgG antibodies increased 19-168-fold from pre-vaccination to post-dose 2 in a dose level-dependent manner. In addition, robust serum bactericidal assay using human complement (hSBA) responses for strains expressing both homologous and heterologous fHBP variants were observed. After three vaccinations, 16-52% of the placebo group and 47-90%, 75-100%, and 88-100%, of the 20, 60, and 200μg dose levels, respectively, had seroprotective (≥ 1:4) hSBA titres against six serogroup B strains. The bivalent r-fHBP vaccine was well tolerated and induced robust bactericidal activity against six diverse serogroup B strains in young adults at the 60 and 200μg dose levels.

Phase 2 Evaluation of Parainfluenza Type 3 Cold Passage Mutant 45 Live Attenuated Vaccine in Healthy Children 6–18 Months Old

A phase 2 evaluation of live attenuated parainfluenza type 3 (PIV3)-cold passage mutant 45 (cp45) vaccine was conducted in 380 children 6-18 months old; 226 children (59%) were seronegative for PIV3. Of the 226 seronegative children, 114 received PIV3-cp45 vaccine, and 112 received placebo. No significant difference in the occurrence of adverse events (i.e., runny nose, cough, or temperature > or =38 degrees C) was noted during the 14 days after vaccination. There was no difference between groups in the occurrence of acute otitis media or serous otitis media. Paired serum samples were available for 109 of the seronegative vaccine recipients and for 110 of the seronegative placebo recipients; 84% of seronegative vaccine recipients developed a > or =4-fold increase in antibody titers. The geometric mean antibody titer after vaccination was 1 : 25 in the vaccine group and <1 : 4 in the placebo group. PIV3-cp45 vaccine was safe and immunogenic in seronegative children and should be evaluated for efficacy in a phase 3 field trial.

Activation of the neutrophil bactericidal activity for nontypable Haemophilus influenzae by tumor necrosis factor and lymphotoxin.

Previous studies have suggested that, in vivo, activated T lymphocytes and neutrophils are important in immunity to nontypable Haemophilus influenzae. We now extend this work by showing that neutrophils pretreated with products of activated T lymphocytes or activated macrophages show significantly enhanced killing of nontypable H. influenzae. Lymphotoxin, a product of activated T lymphocytes, significantly enhanced the neutrophil-mediated killing of nontypable H. influenzae, and tumor necrosis factor, produced by activated T lymphocytes as well as macrophages stimulated by activated T lymphocytes, also significantly increased the bactericidal activity of neutrophils. These cytokine-induced effects were seen with short pretreatment times of neutrophils and were maximal by 30 min. The killing of H. influenzae by neutrophils required the presence of heat-labile opsonins. In the absence of these opsonins, both tumor necrosis factor and lymphotoxin were unable to promote the killing of the bacteria by neutrophils. Furthermore, the results showed that tumor necrosis factor-primed neutrophils displayed significantly increased expression of CR3 and CR4 that was associated with increased phagocytosis of complement-opsonized nontypable H. influenzae. These cytokines may play an important role in immunity toward nontypable H. influenzae by stimulating neutrophil bactericidal activity.

Expression of the costimulator molecules, CD40 and CD154, on lymphocytes from neonates and young children

Differential expression of the costimulator molecules CD40 and CD154 on neonatal lymphocytes may be one explanation for limited T-dependent antibody responses in human neonates. CD40 was expressed at similar levels on resting B cells from adults, young children (2-20 months of age) or cord blood. CD40 expression was higher on cord blood B cells compared to adult B cells after stimulation with PMA and ionomycin, but similar on adult and cord blood B cells activated by CD3-stimulated T cells. In contrast to previous reports, cord blood T cells stimulated with PMA and ionomycin expressed adult levels of CD154 initially, but this expression was more transient on cord blood T cells. When adult and cord blood mononuclear cells were stimulated with CD3 mAb, T cells from some cord blood specimens showed different kinetics of CD154 expression compared with adult T cells. However, some cord blood specimens showed adult patterns of T cell CD154 expression. When mononuclear cells were depleted of B cells and monocytes prior to stimulation with CD3 mAb, the MFI and percentage of T cells expressing CD154 increased, with adult and cord T cells showing similar patterns of expression. These results show some differences in expression of CD40 and CD154 between neonatal and adult lymphocytes, but do not directly account for the relative deficiencies of humoral immunity in neonates.