The ground work for this research thesis was completed seven years ago when the Dow Pharmaceutical Company selected Muncie, Indiana to test their new rubella vaccine. In the Fall of 1970, 311 seronegative elementary school children were innoculated with HPV-77, DK12 rubella vaccine. Of the 302 children who seroconverted, 98 were available for follow-up six years post innoculation. The participant's sera drawn six years previously was recovered in order to determine a six week and six year post innoculation titer on paired specimens. All 98 children, when retested, has measurable antibody. The geometric mean titer six years post innoculation was 55; a 14% decrease from the geometric titer of 64 six weeks after innoculation. At the six year point in time, there was at least a 9.2% incidence of subclinical reinfection, detected by a fourfold rise in the HI-titer, within the study group.Ball State UniversityMuncie, IN 47306

Immunizations are an essential part of children’s healthcare; however, the associated distress can have short- and long-term negative ramifications for children. Parents’ procedural behavior is one of the strongest predictors of children’s distress. The current study evaluated whether an interactive computer training program influenced parents’ knowledge of the impact that their behavior has on their children or their actual procedural behavior during children’s immunizations. 90 parents and their 4- to 6-year-old children receiving immunizations participated. Overall, findings suggest that using a computerized training module to enhance parent knowledge and behavior is helpful but requires improvements in some areas to optimize training.

Syfte: Syftet med denna studie var att jämföra BVC-sjuksköterskors och föräldrars upplevelse av vaccinationstillfället samt skattning av barns smärta i form av skriktid vid två typer av vaccinationstekniker, dubbelvaccinering respektive en injektion i taget, när barnet ska ha två sprutor vid samma vaccinationstillfälle. Metod: Studien är en jämförande deskriptiv studie med kvantitativ ansats. Från både Stockholm och Uppsala valdes 50 barn ut konsekutivt varav 25 barn från Stockholms län samt 25 barn från Uppsala län. Datainsamling skedde med hjälp av enkäter samt mätning av skriktid. Dataanalysen genomfördes med hjälp av chitvåtest samt t-test. Resultat: Det fanns signifikanta skillnader vad gäller både BVC-sjuksköterskors och föräldrars upplevelser av vaccinationsproceduren. Skillnader kunde även ses såväl hos både föräldrar (p=0,020) och BVC-sjuksköterskor (p=0,032) när de fick skatta sin upplevelse av barnets smärta i samband med vaccinationen. Skriktiden visade inte någon signifikant skillnad (p=0,051) mellan de olika vaccinationsteknikerna. Slutsats: Resultatet av denna studie visade att barn som fick dubbelvaccinering upplevdes ha mindre ont när deras smärta skattades av både föräldrar och BVC-sjuksköterskor. Barn som fick sprutorna samtidigt skrek/grät generellt kortare tid än de barn som fick en spruta i taget, skillnaden visade dock ingen signifikans. Flertalat föräldrar i denna studie föredrog dubbelvaccinering. / Aim: The aim of this study was to compare child health center nurses' and parents' experience of the immunization and the child's estimated pain in terms of cry duration when two types of vaccination techniques were used, simultaneous versus sequential immunization injections, when the child are given two shots at the same occasion. Methods: The study is a comparative descriptive study with quantitative approach. From both Stockholm and Uppsala 50 children were selected consecutively with 25 children from the Stockholm and 25 children from the Uppsala. Data collection was done by means of questionnaires and measurement of cry duration. Data analysis was performed using the chi-square test and t-test. Results: There were significant differences from both nurses' and parents' perceptions of the vaccination procedure. Differences could also be seen in terms of the child's pain when both parents' (p=0,020) and nurses' (p=0,032) rated the child's pain associated with the immunization. Cry duration did not show a significant difference (p=0,051) between the two vaccination techniques. Conclusions: The results of this study showed that the children who received two vaccinations simultaneously were experienced by both parents’ and nurses’ to have less pain. Children that received the two injections at the same time cried less in general then the children that received the two injections one by one, the difference was not however significant. Most of the parents in this study preferred that the injections should be given at the same time.

In the past, when deciding the asset allocation, fund managers only concerned the factors of assets. This incomplete way may let pension funds not cover their liabilities. To solve this problem we integrate the factors which influence fund¡¦s assets and liabilities and focus on surplus, which means assets minus liabilities. We use Surplus Optimization Model and Immunization Theory to construct our Liability Driven Investment and Dual Duration Matching Model. We decompose duration to real interest rate duration and inflation rate duration to control the sources of interest rate. Through this method, we can enhance the efficiency of asset allocation to ensure paying pension annuity punctually and avoid the risk of interest rate. Our sample period is Sept. 2001 to Aug. 2005 and sampling frequency is monthly. We use the common investment tools, stocks index, government bond index, 5 years corporate bonds, 3 years bank deposit, 30 days commercial papers, to be the assets we can allocate. We discover that when using liability driven investment and duration matching the longer years we consider the longer assets duration we need. Because government bond index¡¦s duration is shorter than stocks index¡¦s. When we consider longer years the weight of government bond index will decrease and the weight of stocks index will increase. When considered years are 50, the weight of government bond index is 54.74% and the weight of stocks index is 45.26%. The ratio of equity assets to fixed income assets is 84.51% that is similar with pension fund¡¦s ratio, 86.13%. No matter how many years we consider, the weight of bonds is high. But in pension funds¡¦ target allocation the weight of bonds is only 16% and the weights of bank deposit and T-bills are 31%. To take immunization strategy and improve the long term revenue, a large proportion should be allocated from bank deposit and T-bills to bonds.

Master's thesis. / Format: PDF. Bibl.

This dissertation research explores how values regarding sexuality, morality, responsibility, protection, trust, and risk — expressed through parent, daughter, and healthcare provider relationships and interactions — inform parental decisions regarding the Gardasil® vaccine. In particular, the research examines the competing and conflicting meanings that parents and providers ascribe to vaccination and how actors position the vaccine within a wider set of negotiated, value–laden discourses. Because these narratives are situated within a larger structural field that shapes the landscape in which providers and parents interact, relevant historical and structural factors, including vaccine policy, cost, and compensation are discussed.

The development of hybridoma technology nearly forty years ago set the foundation for the use of antibodies in the life sciences. Subsequent advances in recombinant DNA technology have allowed us to adapt antibody genes to various screening systems, greatly increasing the throughput and specialized applications for which these complex biomolecules can be adapted. While selection systems are a powerful tool for discovery and evolution, they can be slow and prone to unintended biases. We see computational approaches as an efficient process for rapid discovery and engineering of antibodies. This is particularly relevant for biodefense and emerging infectious disease applications, for which time is a valuable commodity. In the first chapter of this work, we examine computational protocols for ‘supercharging’ proteins. This process resurfaces the target protein, adding charged moieties to impart specialized functions such as thermoresistance and cell penetration. Current algorithms for resurfacing proteins are static, treating each mutation as an event within a vacuum. The net result is that while several variants can be created, each must be tested experimentally to ensure the resultant protein is functional. In many cases, the designed proteins were severely impaired or incapable of folding. We hypothesize that a more dynamic approach, keeping an eye on energetics and the consequences of mutations will yield a more efficient and robust method for supercharging, successfully adding charges to proteins while minimizing deleterious effects. We continue on this theme applying the successful algorithm to supercharging antibodies for increased function. Utilizing the MS2 model biosensor system, we rationally engineer charges onto the surface of an antibody fragment, increasing thermoresistance, minimizing destabilizing effects, and in some cases actually increasing affinity. Finally, we apply next-generation sequencing approaches to the rapid discovery of antibodies directed against the Zaire Ebolavirus species. We utilize a local immunization strategy to generate a polarized antibody repertoire that is then sequenced to provide a database of antigen-specific variants. This repertoire is probed in silico and individual antibodies selected for analysis, bypassing time- and resource-consuming selection experiments. / text

U.S. immunization and well child-care rates are below desired levels with lower income individuals being at higher risk for receiving inadequate care. To enhance the understanding of motivating factors to health care utilization, this study explored relationships between a mother's interaction style (secure, anxious, avoidant), her reported experiences with pediatric health care and her child's utilization of pediatric health care. Participants included 126 US-born, English-speaking women with an infant 12 to18 months of age. Linear regression analyses found no bivariate associations between maternal interaction style and reported experiences of care. Poisson regression analyses measured associations of maternal interaction style, reported experiences of care, and moderating variables with health care visits and immunizations received. Main effect models found no associations between maternal interaction style and reported experiences of care. Significant associations were identified between provider ratings and sick visits. There were no associations between provider office ratings and utilization rates. When interaction style and provider/provider office ratings were included in the model, high provider ratings (P<.05) and high anxious interaction scores (p<.0001) were associated with more sick visits while higher avoidant interaction style scores (p<.01) were associated with decreased use of sick visits. Multivariate modeling identified provider rating (p<.05) and anxious interaction score (p<.01) as main effects, child's health rating as a confounder, as well as target child being mother's first, WIC/Healthy Start participation, maternal bonding and feelings about going to the doctor acting as moderators to associations between interaction style and sick/follow-up visits. Secure interaction style scores were associated with increased use of emergency department visits, controlling for the confounding effects of maternal bonding and the moderating effects of child's health status and maternal age. Findings indicate that, in some cases, maternal interaction style is associated with how and when mothers access health care for their children. The confounders and moderators identified also highlight the need for more understanding regarding what motivates individuals. Finally, there were racial and ethnic differences including higher rates of avoidant interaction styles in Black, non-Hispanic mothers. Predicting health care utilization patterns will help better target the specific needs of mothers and ultimately improve health outcomes.

Immunotherapy for Alzheimer\'s disease has emerged as a promising approach for clearing pathological tau protein conformers. To explore this kind of treatment we tested an active immunization with pseudo-phosphorylated tau fragments in P301L tangle model mice that develop neuronal tau aggregates as observed in frontotemporal dementia and Alzheimer’s disease. We found that an immunization reduces neurodegeneration in α-motor neurons in the spinal cord and slows progression of the tangle-related behavioral phenotype. Performance on behavioral assays correlated with tau pathology at the corresponding spinal cord level. Interestingly, a slowed progression of these tauopathy related characteristics were only seen in mice that received a specific immunization with pseudo-phosphorylated tau fragments, not in animals that received a non-specific activation of the immune system. An immunization witch pseudo-phosphorylated tau fragments may be a valuable therapeutic option in targeting one of the major hallmarks of Alzheimer’s disease and frontotemporal dementia.

Το δέρμα λειτουργεί σαν μηχανικός φραγμός ενάντια σε ένα εχθρικό περιβάλλον. Παράλληλα λειτουργεί ως ένα ανοσολογικό εμπόδιο, το οποίο είναι πλούσιο σε αντιγονοπαρουσιαστικά κύτταρα, όπως τα κύτταρα Langerhans. Αν και είναι γενικά παραδεκτό ότι το δέρμα δεν είναι περατό από μεγαλομοριακές ουσίες, και συνεπώς δεν μπορεί να χρησιμοποιηθεί ως οδός χορήγησης αντιγόνων, πρόσφατες μελέτες έδειξαν ότι το δέρμα μπορεί να αποτελέσει οδό για τη χορήγηση αντιγόνων. Συγκεκριμένα έδειξαν ότι η διαδερμική χορήγηση ενός αντιγόνου μαζί με την τοξίνη της χολέρας ως ανοσοενισχυτικό επάγει ικανοποιητική ανοσοαπόκριση έναντι του αντιγόνου. Επιπρόσθετα, η διαδερμική χορήγηση της τοξίνης της χολέρας δεν εμφανίζει τοξικότητα όπως με άλλες οδούς χορήγησης. Η υποδόρια χορήγηση αντιγόνων εγκλεισμένων σε PLA και PLGA μικροσφαίρες και νανοσφαίρες έχει ευρεθεί ότι επάγει ισχυρή και μακράς διάρκειας ανοσοαπόκριση. Μέχρι σήμερα δεν έχει μελετηθεί η δυνατότητα διαδερμικής χορήγησης αντιγόνων εγκλεισμένων σε πολυμερικά νανοσωματίδια. Έτσι, στην παρούσα μελέτη μελετήθηκε η ανοσοαπόκριση που λαμβάνεται μετά την διαδερμική χορήγηση οβαλβουμίνης (OVA) εγκλεισμένης σε νανοσφαίρες πολύ (γαλακτικού οξέως) (PLA) σε BALB/c μύες με ή χωρίς την συγχορήγηση ανοσοενισχυτικού, της τοξίνης της χολέρας (CT). Επίσης διερευνήθηκε ο πιθανός μηχανισμός εισόδου των νανοσφαιρών στο άθικτο δέρμα των μυών. Για τη παρούσα μελέτη πραγματοποιήθηκε σε πρώτο στάδιο σύνθεση πολύ (γαλακτικού οξέως) (PLA) το οποίο χαρακτηρίστηκε ως προς το μοριακό του βάρος και ως προς την καθαρότητα του. Επίσης νανοσφαίρες PLA με ενκαψακιωμένη οβαλβουμίνη παρασκευάστηκαν με την μέθοδο του διπλού γαλακτώματος και χαρακτηρίσθηκαν. Στην συνέχεια μελετήθηκε η ικανότητα των νανοσφαιρών να εισχωρούν στο δέρμα μυών μετά από εφαρμογή τους σε περιοχή της πλάτης των μυών από την οποία είχαν απομακρυνθεί οι τρίχες με ξύρισμα. Για αυτή την μελέτη χρησιμοποιήθηκαν αρχικά κενές νανοσφαίρες φθορίζοντος πολυμερούς PLA-pyren-butanol (μονο-επισημασμένες) και νανοσφαίρες φθορίζοντος πολυμερούς PLA-pyren-butanol με ενκαψακιωμένη ροδαμίνη (διπλά-επισημασμένες). Με την βοήθεια φθορίζοντος μικροσκοπίου παρατηρήθηκε ότι οι νανοσφαίρες έχουν εισχωρήσει στις εσωτερικές στοιβάδες του ιστού, σε στοιβάδες αρκετά πιο βαθιά από την κερατίνη στοιβάδα. Στην συνέχεια διερευνήθηκε η οδός εισόδου νανοσφαιρών επισημασμένων με φθορίζουσα αλβουμίνη (FITC-albumin) στο δέρμα χρησιμοποιώντας συνεστιακό μικροσκόπιο σάρωσης (confocal laser microscopy). Παρατηρήθηκε ότι οι νανοσφαίρες εμφανίστηκαν ικανές να διεισδύουν στο εσωτερικό του δέρματος μέσω των θυλάκων των τριχών του ιστού ενώ δεν παρατηρήθηκε άλλη οδός εισόδου των νανοσφαιρών στο εσωτερικό του δέρματος Για την ανίχνευση της ειδικής ανοσοαπόκρισης μελετήθηκαν αντιοροί προς την ολική ΙgG και των ισοτύπων IgG1 και IgG2a έναντι της οβαλβουμίνης. Επίσης πραγματοποιήθηκαν πειράματα σε κυτταρικό επίπεδο στα σπληνοκύτταρα που ελήφθησαν από τους μύες οι οποίοι ανοσοποιήθηκαν διαδερμικά, με την μέτρηση του πολλαπλασιασμού των σπληνοκυττάρων και μετρήθηκαν τα επίπεδα των κυτταροκινών (IL-4, IL-10, IFN-γ και IL-2) στα υπερκείμενα καλλιεργειών των σπληνοκυττάρων κατόπιν in vitro διέγερσης με το αντιγόνο. Στο πρώτο μέρος της μελέτης έγινε διαδερμική χορήγηση (σε ξυρισμένη περιοχή της πλάτης) διαφορετικών μορφών αντιγόνου (ενκαψακιωμένη ή ελεύθερη οβαλβουμίνη και παρουσία ή απουσία ανοσοενισχυτικού). Οι νανοσφαίρες με το αντιγόνο παρουσίασαν παρόμοια επίπεδα ολικών αντισωμάτων IgG με την ελεύθερη οβαλβουμίνη (οβαλβουμίνη σε υδατικό διάλυμα). Επιπρόσθετα, και με τις δύο μορφές χορήγησης του αντιγόνου (διάλυμα και νανοσφαίρες) η συγχορήγηση τοξίνης της χολέρας προκάλεσε αύξηση της παραγωγής αντισωμάτων IgG. Μεγαλύτερη αύξηση παρατηρήθηκε στην περίπτωση των νανοσφαιρών. Τα αποτελέσματα του πειράματος σε κυτταρικό επίπεδο δείχνουν ότι οι νανοσφαίρες με το ενκαψακιωμένο αντιγόνο συν το ανοσοενισχυτικό προκάλεσαν αρκετά υψηλότερες αποκρίσεις IFN-γ σε σύγκριση με όλες τις υπόλοιπες μορφές χορήγησης. Στο δεύτερο μέρος της μελέτης διερευνήθηκε πρωταρχικά η ικανότητα της διαδερμικής χορήγησης ενκαψακιωμένου και μη-ενκαψακιωμένου αντιγόνου (OVA) να επάγει αυξημένη ανοσοαπόκριση μετά από μετέπειτα «πρόκληση» με το αντιγόνο (priming efficiency) και δευτερευόντως η ανοσοαπόκριση που λαμβάνεται με την συνχορήγηση μικρότερης δόσης ανοσοενισχυτικού (50μg τοξίνης της χολέρας ανά μυ). Διαπιστώθηκε ότι η συνχορήγηση έστω και μικρότερης δόσης ανοσοενισχυτικού προκαλεί βελτίωση της ανοσοαπόκρισης σε αντισώματα, ιδιαίτερα στην περίπτωση του ελεύθερου αντιγόνου. Πιο σημαντικό όμως ίσως είναι ότι τα επίπεδα ολικής IgG μετά από υποδόρια χορήγηση 50 μg OVA ανά μυ (δόση «πρόκλησης») σε μύες που είχαν ήδη ανοσοποιηθεί με δύο διαδερμικές δόσεις ενκαψακιωμένης και μη-ενκαψακιωμένης OVA ήταν υψηλότερα (περίπου διπλάσια με όλες τις μορφές χορήγησης) από τα επίπεδα ολικής IgG που λήφθηκαν από μύες που δέχτηκαν μονάχα την υποδόρια δόση με το αντιγόνο. Σε κυτταρικό επίπεδο, οι νανοσφαίρες παρουσίασαν ελαφρώς υψηλότερα επίπεδα παραγωγής IFN-γ και IL-2 από το διάλυμα του αντιγόνου ενώ επέδειξαν παρόμοια επίπεδα IL-4 και IL-10 με το διάλυμα του αντιγόνου. Τα επίπεδα των IFN-γ και IL-2 που μετρήθηκαν για τις νανοσφαίρες με το αντιγόνο συν το ανοσοενισχυτικό ήταν σημαντικά υψηλότερα από όλες τις άλλες μορφές χορήγησης του αντιγόνου. Με βάση τα αποτελέσματα αυτά φαίνεται ότι σε κυτταρικό επίπεδο η διαδερμική χορήγηση του αντιγόνου ενκαψακιωμένου σε PLA νανοσφαίρες πλεονεκτεί της χορήγησης του ελεύθερου αντιγόνου. Τα αυξημένα επίπεδα IFN-γ και IL-2 με την ενκαψακιωμένη μορφή του αντιγόνου είναι πιθανόν να σχετίζονται με αλλαγή της ισορροπίας της ανοσοαπόκρισης προς μία περισσότερο Th1 κατεύθυνση. Οι διαφορές που προκύπτουν στην ανοσογονική συμπεριφορά μεταξύ της ενκαψακιωμένης οβαλβουμίνης στις νανοσφαίρες και της ελεύθερης οβαλβουμίνης μπορεί να οφείλονται στον διαφορετικό τρόπο πρόσληψης και παρουσίασης του αντιγόνου από τα ανοσοπαρουσιαστικά κύτταρα. Η διαδερμική χορήγηση του αντιγόνου ενκαψακιωμένου σε νανοσφαίρες PLA δεν παρείχε σημαντικό πλεονέκτημα όσον αφορά την χυμική ανοσοαπόκριση (παραγωγή αντισωμάτων) σε σύγκριση με την διαδερμική χορήγηση ελεύθερου αντιγόνου. Τα αποτελέσματα της παρούσας μελέτης δείχνουν ότι το σύστημα διαδερμικής χορήγησης του αντιγόνου (η σύνθεση του διαδερμικού «εμβολίου») έχει σημαντική επίδραση στην λαμβανόμενη ανοσοαπόκριση και δικαιολογούν την περαιτέρω μελέτη της χρησιμότητας των PLA νανοσφαιρών στην διαδερμική χορήγηση αντιγόνων. / The skin is part of the epithelial system of the body, which serves as an effective barrier against a potentially hostile environment. As a structural barrier, the skin keeps water and other vital substances in and foreign material out. As an immunological barrier the skin is rich of immunocompetent cells, such as Langerhans cells. Recent studies have demonstrated the potential of skin as a non-invasive route for administering antigens. In the case of protein antigens, the skin barrier limits the penetration of high molecular weight molecules, preventing their use for therapeutic purposes. However, co-administration of proteins with cholera toxin (CT) has been shown to enhance protein-specific antibody responses. Also, CT was not toxic when applied onto bare skin. Using non-invasive routes such as the skin for vaccine delivery could be advantageous for vaccination for several reasons. Subcutaneous delivery of antigen-loaded PLA- and PLGA-microspheres and nanospheres has been found capable of inducing efficient and long-lasting immune responses. In the present study we investigated the immune responses obtained after transcutaneous administration of a model antigen (ovalbumin, OVA) encapsulated in PLA nanospheres. OVA-loaded PLA nanospheres were applied onto bare skin of Balb/c mice in the presence or the absence of CT and the immune responses obtained were compared to those obtained with free OVA (OVA aqueous solution). Also, we investigated the possible route of entry of the nanospheres in the skin. PLA polymer was synthesized by melt polymerization. OVA-loaded nanospheres were prepared by a double emulsion technique. We investigated the ability of nanospheres labeled with one fluorescent dye (1- pyrene-butanol coupled to PLA) and nanospheres labeled with two fluorescent dyes (1-pyrene-butanol/PLA and dextran-rhodamine) to penetrate into the mouse skin using fluorescent microscopy. The results indicated that the nanospheres were capable of entering into the inner layers of the skin. Then, we investigated the possible route of nanospheres entrance into the skin using confocal laser microscopy. The nanopsheres appeared capable to enter the skin only through the duct of the hair follicles. We did not observe other modes of nanospheres entry into the skin in any of the skin samples examined. We proceeded in the evaluation of immune responses elicited after transcutaneous immunization with OVA aqueous solution and OVA-loaded PLA nanospheres. For the evaluation of the immune responses, total IgG, IgG1 and IgG2a levels were measured in anti-serum samples. We also measured the proliferative responses of splenocytes retrieved from the immunized mice and the IFN-γ, IL-2, IL-4 and IL-10 responses in the supernatant of cultured splenocytes after in vitro stimulation with OVA. On the first stage of the study, we transcutaneously immunized mice onto their bare back with OVA in solution or OVA-loaded nanospheres (200 μg OVA per mouse) in the presence or absence of CT (100 μg CT per mouse). The OVA-loaded nanospheres elicited similar total IgG responses with the OVA solution. With both modes of antigen delivery (aqueous solution and nanospheres-entrapped), the coadministration of CT adjuvant increased IgG response, especially that obtained with the OVA-loaded nanospheres. Also, the OVA-loaded nanospheres plus CT exhibited higher IFN-γ responses than the other formulations tested but similar IL-4 and IL-10 responses. On the second stage of the study, we investigated mainly the ability of transcutaneous delivery of OVA-loaded nanospheres and OVA solution to induce an increased immune response after a subcutaneous booster (“challenge”) with the antigen. Also, we investigated the immune responses obtained by transcutaneous immunization with a lower dose of CT. We observed that even a relatively small amount of CT (50 μg per mouse) could augment antibody responses, especially in the case of the free antigen. It is important to note that the IgG responses obtained after subcutaneous booster with OVA (50 μg per mouse) of mice previously primed with 2 transcutaneous doses of the different OVA formulations were significantly higher than the IgG responses obtained by mice which received only the subcutaneous dose of OVA. This would indicate that transcutaneous administration of antigens in the form of aqueous solution or antigen-loaded nanospheres can prime antibody responses (can induce “memory” response). All formulations elicited both IgG1 and IgG2a responses, indicating a balanced type of immune response. The OVA-loaded nanospheres exhibited a little higher IFN-γ and IL-2 responses than the OVA-solution and similar IL-4 and IL-10 responses with the OVA solution. On the other hand, the OVA-loaded nanospheres plus CT induced much higher IFN-γ and IL-2 responses than all other formulations tested. These results indicate that as far as the cellular responses induced by transcutaneous antigen administration is concerned it may be advantageous to deliver the antigen in nanosphere-encapsulated form rather than in free (aqueous solution) form. The increased IFN-γ and IL-2 levels obtained with the encapsulated forms of OVA compared to the soluble forms of OVA may indicate a possibility of altering the balance of immune response towards a Th1-type of response using nanosphere-encapsulated antigens. The differences in the immunogenic behavior between the encapsulated antigen (OVA entrapped in nanospheres) and free antigen (OVA solution) may arise from the facilitated uptake and presentation of the encapsulated antigen by antigen presenting cells. Taking into account that the encapsulation of OVA in the nanospheres was accompanied by a significant (around 30%) reduction of OVA antigenicity, it might be expected that optimized OVA-loaded nanospheres, in which the protein would retain its full antigenic potential, could have resulted to more potent IgG responses than those obtained in this study. The results of the present study reveal that the type of antigen formulation could have a pronounced effect on the immune response obtained after transcutaneous administration of the antigen and justify the further investigation of the possible advantages of using PLA nanospheres as the antigen delivery system in transcutaneous immunization.