Ex vivo restimulation of human PBMC expands a CD3+CD4-CD8- γδ+ T cell population that can confound the evaluation of CD4 and CD8 T cell responses to vaccination.

The measurement of vaccine-induced humoral and CD4(+) and CD8(+) cellular immune responses represents an important correlate of vaccine efficacy. Accurate and reliable assays evaluating such responses are therefore critical during the clinical development phase of vaccines. T cells play a pivotal role both in coordinating the adaptive and innate immune responses and as effectors. During the assessment of cell-mediated immunity (CMI) in subjects participating in a large-scale influenza vaccine trial, we identified the expansion of an IFN-γ-producing CD3(+)CD4(-)CD8(-) γδ (+) T cell population in the peripheral blood of 90/610 (15%) healthy subjects. The appearance of CD3(+)CD4(-)CD8(-) γδ (+) T cells in the blood of subjects was transient and found to be independent of the study cohort, vaccine group, subject gender and ethnicity, and ex vivo restimulation conditions. Although the function of this population and relevance to vaccination are unclear, their inclusion in the total vaccine-specific T-cell response has the potential to confound data interpretation. It is thus recommended that when evaluating the induction of IFN-γ-producing CD4(+) and CD8(+) immune responses following vaccination, the CD3(+)CD4(-)CD8(-) γδ (+) T cells are either excluded or separately enumerated from the overall frequency determination.

The impact of two-dimensional versus three-dimensional ultrasound exposure on maternal-fetal attachment and maternal health behavior in pregnancy.

OBJECTIVE: To explore the impact of timing and type of ultrasound, particularly three-dimensional (3D), exposure on maternal-fetal attachment and maternal health behavior during pregnancy. METHODS: Subjects were 68 women aged 18 years or older expecting their first child who presented for a routine ultrasound scan at around either 12 or 18 weeks' gestation in Nepean Hospital, Western Sydney. Women completed questionnaires assessing maternal-fetal attachment and health behavior, and were then allocated arbitrarily to either two-dimensional (2D) or 3D ultrasound examination. Repeat questionnaires were completed 1 week later. RESULTS: Maternal-fetal attachment increased after both 2D and 3D ultrasound exposure, and the effect was moderated by the timing of exposure, with women receiving their first ultrasound examination at around 12 weeks showing the greatest change. Alcohol consumption was the only behavior to show significant change following ultrasound exposure, with a reduction in the reported average number of drinks per week. There was no significant difference in the pattern of change for 2D compared with 3D ultrasound exposure, and no effect of ultrasound exposure on maternal perception of the fetus. CONCLUSIONS: Ultrasound has a positive impact on maternal-fetal attachment, particularly in the first trimester. 3D ultrasound did not offer enhanced benefits. Associations between ultrasound exposure and alcohol consumption warrant further investigation. Larger samples are needed to clarify the moderating effects of gestational age and type of ultrasound exposure.

Injectable silicone implants as vaccine delivery vehicles.

Injectable silicone implants were assessed as vaccine delivery vehicles in sheep, using either the model antigen avidin or Clostridium tetani and Clostridium novyi toxoids. Two types of implant were compared, the matrix type, that has been shown to deliver antigen in vitro in a first-order profile over approximately 1 month, and the covered rod type, that delivers antigen for several months in a zero-order profile. The implants were prepared using lyophilized antigen and adjuvant (in this case, recombinant ovine interleukin-1beta; rovIL-1beta) and manufactured in the absence of extremes of temperature or pH or the use of organic solvents. Use of the matrix type implant was capable of inducing antibody responses equivalent to those induced by conventional vaccination with aluminium hydroxide adjuvant ("alum"). The use of the covered rod implants, that release very low levels of antigen over a long period, induced responses that were markedly enhanced over the alum control groups. The covered rod implant also favoured production of both IgG1 and IgG2 isotypes in contrast to responses of matrix-vaccinated sheep and conventionally vaccinated control sheep in which IgG1 predominated. Prolonged duration of the antibody response was also observed following vaccination with covered rod implants. Dose-response analysis using the matrix implant demonstrated a trend towards improved responses for lower antigen doses. Clostridial vaccination of sheep showed that protective antibody titres up to 4-fold higher than for alum-adjuvanted groups could be induced by administering the antigen in the covered rod implant. Responses elicited by all implant groups were dependent on the inclusion of adjuvant into the implant formulation.

The application of biodegradable collagen minipellets as vaccine delivery vehicles in mice and sheep.

Collagen minipellets are injectable delivery vehicles that release antigen and adjuvant over several days in a first-order release profile. In vaccination experiments in mice, secondary antibody responses induced by minipellets formulated with avidin and IL-1beta as adjuvant were equivalent to those induced by a conventional immunization with avidin in alum. When no adjuvant was used, anti-avidin responses induced by minipellets were 10-20-fold higher than those induced by injection of avidin in saline. In sheep, conventional vaccination with avidin in alum induced antibody responses initially exceeding that induced by minipellets formulated with avidin and IL-1beta, while following a secondary vaccination, the minipellet antibody response was equal to or greater than the alum-adjuvanted control groups. Increasing levels of IL-1beta adjuvant resulted in enhanced persistence of the antibody response. When clostridial vaccine antigens were incorporated into the minipellets, total antibody responses induced in sheep were equivalent to those induced by vaccination with the clostridial antigens in alum. Neutralizing antibody titres exceeded those induced by conventional vaccination. No adverse site reactions were observed at the implant site, with immunohistological study showing that the cellular infiltrate was dominated by a transient influx of neutrophils. This is a typical response to delivery of bioactive IL-1beta. The minipellets were completely degraded within 35 days of implantation.