Evaluating the possible genotoxicity of nanoaluminum incorporated in human vaccines and the potential protective role of nanocurcumin: an in vivo study.

For nearly 90 years, aluminum (Al) salts have been utilized as vaccination adjuvants. Nevertheless, there is a risk of adverse effects associated with the amount of nanoaluminum used in various national pediatric immunization regimens. This study aimed to investigate the possible genotoxic effects of nanoaluminum incorporated in human vaccines on the brains of newborn albino rats and whether nanocurcumin has a potential protective effect against this toxicity. Fifty newborn albino rats were randomly assigned to 5 groups, with 10 in each group. Groups 1 and 2 received "high" and "low" Al injections corresponding to either the American or Scandinavian pediatric immunization schedules, respectively, as opposed to the control rats (group 5) that received saline injections. Groups 3 and 4 received the same regimens as groups 1 and 2 in addition to oral nanocurcumin. The expression of both the cell breakdown gene tumor protein (P53) and the cell stress gene uncoupling protein 2 (UCP2) was significantly greater in groups 1 and 2 than in group 5. Groups 1 and 2 exhibited severe DNA fragmentation, which was observed as DNA laddering. Nanocurcumin significantly reduced the expression of the P53 and UCP2 genes in groups 3 and 4, with very low or undetectable DNA laddering in both groups. Vaccination with nanoaluminum adjuvants can cause genotoxic effects, which can be mediated by the inflammatory response and oxidative stress, and nanocurcumin can protect against these toxic effects through the modulation of oxidative stress regulators and gene expression.

Toxicologic Pathology Forum: Tissue Evaluation in Nonclinical Toxicity Studies for Prophylactic Vaccines.

Nonclinical toxicity testing (GLP) of prophylactic vaccines to support human clinical trials is outlined in the World Health Organization nonclinical vaccine-development guidelines, which are followed by most regulatory agencies globally. Vaccine GLP toxicity studies include at least two groups: a buffer control (often phosphate-buffered saline) group and a highest anticipated clinical dose formulation group. However, studies may include additional groups, including lower-dose formulation groups and adjuvant-containing formulation control groups. World Health Organization guidelines touch upon expectations for dose group and tissue selection for microscopic evaluation, but there is variation in the interpretation of this aspect of these guidelines between vaccine developers. This opinion piece proposes a scientifically based approach for defining appropriate groups to evaluate in the dosing and recovery phases in nonclinical vaccine toxicity studies, as well as suggestions on selecting tissues for microscopic evaluation at the recovery phase of studies to promote alignment between vaccine manufacturers.

A novel method for deriving thresholds of toxicological concern for vaccine constituents.

Safety assessment evaluating the presence of impurities, residual materials, and contaminants in vaccines is a focus of current research. Thresholds of toxicological concern (TTCs) are mathematically modeled levels used for assessing the safety of many food and medication constituents. In this study, six algorithms are selected from the open-access ToxTree software program to derive a method for calculating TTCs for vaccine constituents: In Vivo Rodent Micronucleus assay/LD50, Benigni-Bossa/LD50, Cramer Extended/LD50, In Vivo Rodent Micronucleus assay/TDLo, Benigni-Bossa/TDLo, and the Cramer Extended/TDLo. Using an initial dataset (n = 197) taken from INCHEM, RepDose, RTECS, and TOXNET, the chemicals were divided into two families: "positive" - based on the presence of structures associated with adverse outcomes, or "negative" - no such structures or having structures that appear to be protective of health. The final validation indicated that the Benigni-Bossa/LD50 method is the most appropriate for calculating TTCs for vaccine constituents. Final TTCs were designated as 18.06 µg/person and 20.61 µg/person for the Benigni-Bossa/LD50 positive and negative structural families, respectively.

[Immunological adjuvants. Determinant factors in the efficacy-toxicity ratio of the contemporary vaccines]. / Adyuvantes inmunológicos. Determinantes en el balance eficacia-toxicidad de las vacunas contemporáneas.

To achieve effective and safe vaccines for the prevention of not yet controlled or re-emergent infectious diseases, one of the more importance aspects is to have immunological adjuvants that allow inducing a protective immune response with an appropriate safety profile. Since 1926 the aluminium compounds have been used as adjuvants for human vaccines, and only in the last 10 years have some new products been registered. Although there an enormous quantity of proposed candidates, the toxicity is the main factor that has limited their introduction into the clinic. In this work the mechanism of action are updated, and the toxicity of the immunological adjuvants are revised, especially those that have obtained clinical approval or are close to getting it.

Formulation of Nanovaccines toward an Extended Immunity against Nicotine.

Nicotine vaccines have been investigated to assist with smoking cessation. Because smoking cessation is a long process, past nicotine vaccines required multiple injections to achieve long-term efficacy. It would be of great significance if extended efficacy can be achieved with fewer injections. Here, we report the assembly of lipid-polylactic acid (PLA) and lipid-poly(lactic-co-glycolic acid) (PLGA) hybrid nanoparticle (NP) based nicotine vaccines. Mice immunized with the lipid-PLGA vaccine produced higher titers of nicotine-specific antibodies than the lipid-PLA vaccine in short-term. However, the lipid-PLA vaccine was found to induce long-lasting antibodies. Three months after the immunization, only mice that received first two injections of the lipid-PLGA vaccine and a third injection of the lipid-PLA vaccine achieved a significantly lower brain nicotine concentration of 65.13 ± 20.59 ng/mg than 115.88 ± 37.62 ng/mg from the negative controls. The results indicate that not only the stability of the vaccines but also the combination of the vaccines impacted the long-term efficacy of the immunization. Lastly, both the body weight and the histopathology study suggest that the vaccines were safe to mice. These findings suggest that long-term immunity against nicotine can be realized by a rational administration of nanovaccines of different levels of stability.

Pharmacogenomics in the preclinical development of vaccines: evaluation of efficacy and systemic toxicity in the mouse using array technology.

The development of vaccines, conventional protein based as well as nucleic acid based vaccines, and their delivery systems has been largely empirical and ineffective. This is partly due to a lack of methodology, since traditionally only a few markers are studied. By introducing gene expression analysis and bioinformatics into the design of vaccines and their delivery systems, vaccine development can be improved and accelerated considerably. Each vaccine antigen and delivery system combination is characterized by a unique genomic profile, a "fingerprint" that will give information of not only immunological and toxicological responses but also other related cellular responses e.g. cell cycle, apoptosis and carcinogenic effects. The resulting unique genomic fingerprint facilitates the establishment of molecular structure--pharmacological activity relationships and therefore leads to optimization of vaccine development.

Efficacy and safety of immunological adjuvants. Where is the cut-off?

Research over the past several decades has provided insight into the mode of action of adjuvants. However, the main focus of attention has been the efficacy in the induction of protective immunogenicity, while less effort has been devoted to the study of toxicity mechanisms. Evidences suggest that several mechanisms that are responsible for the immunostimulating effects are, at the same time, responsible of the adverse effects. In this context, it is often very difficult to establish the boundaries between immunostimulation and immunotoxicity to reach the ideal balance of efficacy/safety. During decades, hundreds of adjuvants and adjuvant formulations have been proposed as immunostimulants for vaccines but very few have been used in human vaccines due to toxicity concerns. In this review, relevant aspects about immunotoxicology of adjuvants, based on clinical and experimental studies are discussed. Some effects are only observed under hyperstimulating regimens using non-approved adjuvants for human use, but these are nonetheless useful to understanding basic principles of adjuvant toxicity. The acute local and systemic reactions, during the first hours and those that can be observed after the third day of vaccination in the inoculation site and systemically are discussed.

A vaccine for hypertension based on virus-like particles: preclinical efficacy and phase I safety and immunogenicity.

BACKGROUND: Despite the availability of efficacious drugs, the success of treating hypertension is limited by patients' inconsistent drug intake. Immunization against angiotensin II may offer a valuable alternative to conventional drugs for the treatment of hypertension, because vaccines induce relatively long-lasting effects and do not require daily dosing. Here we describe the preclinical development and the phase I clinical trial testing of a virus-like particle (VLP)-based antihypertensive vaccine. METHODS AND RESULTS: An angiotensin II-derived peptide was conjugated to the VLP Qbeta (AngQb). AngQb was highly immunogenic in mice and rats. To test for efficacy, spontaneously hypertensive rats (SHR) were immunized with 400 microg AngQb or VLP alone. Group mean systolic blood pressure (SBP) was reduced by up to 21 mmHg (159 +/- 2 versus 180 +/- 5 mmHg, P < 0.001), and total angiotensin II levels (antibody-bound and free) were increased ninefold (85 +/- 20 versus 9 +/- 1 pmol/l, P = 0.002) compared with VLP controls. SHR treated with the angiotensin-converting enzyme (ACE) inhibitor ramipril (1 mg/kg per day by mouth) reached an SBP of 155 +/- 2 mmHg. Twelve healthy volunteers of a placebo-controlled randomized phase I trial were injected once with 100 microg AngQb. Angiotensin II-specific antibodies were raised in all subjects (100% responder rate) and AngQb was well tolerated. CONCLUSIONS: AngQb reduces blood pressure in SHR to levels obtained with an ACE inhibitor, and is immunogenic and well tolerated in humans. Therefore, vaccination against angiotensin II has the potential to become a useful antihypertensive treatment providing long-lasting effects and improving patient compliance.

A rationally designed peptide IA-2-P2 against type 1 diabetes in streptozotocin-induced diabetic mice.

Recent studies have investigated the potential of type 1 diabetes mellitus-related autoantigens, such as heat shock protein 60, to induce immunological tolerance or to suppress the immune response. A functional 24-residue peptide derived from heat shock protein 60 (P277) has shown anti-type 1 diabetes mellitus potential in experimental animals and in clinical studies, but it also carries a potential atherogenic effect. In this study, we have modified P277 to retain an anti-type 1 diabetes mellitus effect and minimize the atherogenic potential by replacing the P277 B epitope with another diabetes-associated autoantigen, insulinoma antigen-2 (IA-2), to create the fusion peptide IA-2-P2. In streptozotocin-induced diabetic C57BL/6J mice, the IA-2-P2 peptide displayed similar anti-diabetic effects to the control P277 peptide. Also, the IA-2-P2 peptide did not show atherogenic activity in a rabbit model. Our findings indicate the potential of IA-2-P2 as a promising vaccine against type 1 diabetes mellitus.

Risks and benefits of immunizing pregnant women: the risk of doing nothing.

The medical, social and legal risks of immunizing pregnant women are obstacles preventing the initiation of programs to immunize women for their protection and for their infant's protection. Recent projects devoted to vaccine development have focused on protecting newborns and infants. But there are many other reasons for developing or utilizing vaccines before or during pregnancy, beyond the protection of the newborn. Besides the usual reasons for utilizing immunizations to protect the mother and the neonate, the threat of bio-terrorism adds a new dimension to the necessity for addressing this issue. The potential advantages for thinking about vaccinating pregnant women include an array of possible programs associated with risks and benefits. The immunization of pregnant women or women of reproductive age has multiple purposes: to protect the mother, to protect the newborn and infant and to prevent diseases and complications of pregnancy. (1) Preparation of vaccines against infectious agents that are known to result in reproductive pathology and congenital malformation if the infection of the mother occurs during pregnancy. (2) To utilize vaccines used routinely to protect the non-pregnant population, for administration during pregnancy, i.e., influenza, tetanus and other vaccines. Should these vaccines and other routinely used vaccines for children and non-pregnant adults be administered to women during pregnancy if they are medically indicated? (3) Utilization of vaccines to protect women from diseases to which they are susceptible because of pregnancy (poliomyelitis, hepatitis). (4) Utilization of vaccines for use before or during pregnancy, primarily to protect the newborn and infant via maternal transplacental antibodies, i.e., GBD (group B streptococcus). (5) The prevention of intrauterine infection that has been alleged to initiate premature labor. (6) The preparation of a vaccine for use before or during pregnancy to protect both the mother and the neonate, i.e., botulism toxin vaccine. The regulatory agencies and the vaccine producers will need a great deal of objective scientific advice and support and it is the scientific community's responsibility to provide that support. If the scientific and medical community ignores the opportunity to develop vaccines that could reduce the occurrence of reproductive and developmental problems, then we can be accused of acquiescing to the "risk of doing nothing."

Rapid induction of autoantibodies against Nogo-A and MOG in the absence of an encephalitogenic T cell response: implication for immunotherapeutic approaches in neurological diseases.

Vaccinations against various antigens of the central nervous system (CNS) are gaining increasing interest as a therapeutic approach in a variety of neurological diseases such as spinal cord injury, ischemic stroke, Alzheimer disease, or spongiform encephalopathy. In the present work, the time window after spinal cord injury allowing potentially therapeutic antibody to penetrate the damaged blood-brain barrier (BBB) was measured by intravenous injection of a monoclonal anti-Nogo-A antibody. Although an influx of Nogo antibodies at the lesion site was detectable up to 2 wk after injury, a significant decrease in BBB permeability was noticed within the first week. Clearly, therefore, a vaccination protocol with a rapid antibody response is required for acute therapeutic interventions after CNS trauma. We designed a conjugate vaccine paradigm with particular focus on the safety and the kinetics of the antibody response. As antigen targets, we used Nogo-A and the strongly encephalitogenic myelin-oligodendrocyte glycoprotein (MOG). Intrasplenic autoimmunization of rats with a Nogo-A-specific region fused to the Tetanus toxin C-fragment (TTC) resulted in a fast IgM response against Nogo-A. A specific switch to IgG was observed as soon as 4-7 days after intrasplenic immunization in TTC-primed animals. In spite of the induction of a specific IgG response after intrasplenic immunization, no signs of experimental autoimmune disease (EAE) or inflammatory infiltrates on histological examinations were observable. In contrast to subcutaneous immunization with MOG, in vitro cytokine secretion assays (IL-2, IL-10, and IFN-gamma) did not reveal activation of MOG-specific T cells after intrasplenic immunization. Our findings have critical implications for future strategies in the development of safe and efficient therapeutic vaccines for neurological diseases.

Poxvirus-based vectors as vaccine candidates.

The advent of recombinant DNA techniques and advances in immunology have provided a means for dissecting the immunobiology of disease-causing agents. Identification and expression of individual genes from the pathogens in heterologous systems, such as VV, have yielded valuable information regarding structural properties of the gene products and their role in eliciting protective immunity. Targets of both humoral and/or cellular immunity for many disease-causing agents have been identified or confirmed using a VV expression system (Section IV). Additionally, specific VV recombinants have induced a protective immune response in experimental animals. The ability of VV recombinants to induce pertinent immune responses necessary for protection, the potential to develop polyvalent vaccines, and the successful history of VV as an immunizing agent provide the impetus for engineering VV as a live recombinant vaccine candidate. Critical to the refinement of poxviruses as recombinant immunizing agents is a more in-depth knowledge of the molecular biology of these viruses. Although significant advances have been made in this area within the past 10 years, a greater understanding of the mechanisms governing gene expression and viral virulence factors should enable the development of more safe and effective vaccine candidates. Progression of VV vector technology to other members of the poxvirus family has been successful. Development of other poxviruses as vectors may, therefore, provide a means of generating host-restricted vaccines. Fowlpox recombinant viruses, for instance, may yield candidate vaccines in the poultry industry. Interestingly, it was also demonstrated that these host-restricted recombinant viruses can be used as immunizing vehicles in other species. The ability of a nonreplicating viral vector to elicit a protective immune response is especially intriguing in light of the observation by Morgan et al. that a VV/EBV gp340/220 recombinant, derived from an avirulent VV strain, was unable to protect cottontop tamarins from a live EBV challenge.

Myositis, lameness, and recumbency after use of water-in-oil adjuvanted vaccines in near-term beef cattle.

A producer administered 2 US Department of Agriculture-licensed adjuvanted veterinary vaccines (inactivated bovine rotavirus-coronavirus vaccine; Clostridium perfringens type C-Escherichia coli bacterin-toxoid) into muscles of the left and right hips of 469 pregnant beef cows. Within 24 hours, 5 cattle were recumbent, and another 2 had non-weight bearing pelvic limb lameness (1.5% affected; 7/469). During the next 10 days, 50% of the herd developed firm swellings up to 24 cm in vaccination sites in muscles of the hip. Histological samples revealed granulomatous myositis with intralesional oil. Lesions resolved slowly during the next 6 months. Six cattle were injected experimentally with the vaccines. None became lame, but all developed foreign body granulomatous myositis similar to those in the affected herd. The maximum diameter of experimentally induced lesions in muscle at necropsy 60 days after injection with the recommended dose of the bacterin-toxoid vaccines was 12 cm. Histological examination revealed pyogranulomatous myositis, fibrosis, and myonecrosis. The inactivated viral vaccine induced milder granulomatous myositis with intralesional lipid and scant fibrosis. Acute transient lameness on the ranch was attributed to use of 2 irritating biological vaccines in the hip muscles of cows that were close to parturition.

Safety assessment of adjuvanted vaccines: Methodological considerations.

Adjuvants mainly interact with the innate immune response and are used to enhance the quantity and quality of the downstream adaptive immune response to vaccine antigens. Establishing the safety of a new adjuvant-antigen combination is achieved through rigorous evaluation that begins in the laboratory, and that continues throughout the vaccine life-cycle. The strategy for the evaluation of safety pre-licensure is guided by the disease profile, vaccine indication, and target population, and it is also influenced by available regulatory guidelines. In order to allow meaningful interpretation of clinical data, clinical program methodology should be optimized and standardized, making best use of all available data sources. Post-licensure safety activities are directed by field experience accumulated pre- and post-licensure clinical trial data and spontaneous adverse event reports. Continued evolution of safety evaluation processes that keep pace with advances in vaccine technology and updated communication of the benefit-risk profile is necessary to maintain public confidence in vaccines.

Gold nanocluster-based vaccines for dual-delivery of antigens and immunostimulatory oligonucleotides.

We here report a facile one-pot synthesis of fluorescent gold nanoclusters (AuNCs) via the peptide biomineralization method, which can elicit specific immunological responses. The as-prepared peptide-protected AuNCs (peptide-AuNCs) display strong red fluorescence, and more importantly, as compared to the peptide alone, the immune stimulatory ability of the resulting peptide-AuNCs can not only be retained, but can also be efficaciously enhanced. Moreover, through a dual-delivery of antigen peptides and cytosine-phosphate-guanine (CpG) oligodeoxynucleotides (ODNs), the as-prepared peptide-AuNC-CpG conjugates can also act as smart self-vaccines to assist in the generation of high immunostimulatory activity, and be applied as a probe for intracellular imaging. Both in vitro and in vivo studies provide strong evidence that the AuNC-based vaccines may be utilized as safe and efficient immunostimulatory agents that are able to prevent and/or treat a variety of ailments.

Ocular safety and efficacy of an HSV-1 gD vaccine during primary and latent infection.

One potential complication of systemic herpes simplex virus (HSV) vaccination is that subsequent ocular infection may lead to increased immunogenic corneal scarring. Therefore, V52, a genetically engineered vaccinia virus that expresses the HSV-1 glycoprotein gD, was tested for ocular safety and for protection against ocular challenge with a stromal-disease-producing strain (McKrae) of HSV-1. To maximize immune response, rabbits were vaccinated by a series of inoculations. V52-vaccinated rabbits developed significant HSV-1 neutralizing antibody titers; however, they were not as high as those induced by vaccination with live HSV-1 McKrae. One month after the final vaccination, all rabbits were challenged ocularly. Eyes were monitored for 35 days for epithelial keratitis, stromal keratitis, and iritis. In no case was epithelial keratitis, stromal keratitis, or iritis significantly exacerbated by vaccination. The gD V52 recombinant vaccine provided protection against HSV-1 induced epithelial keratitis (P = 0.02) and long-term stromal scarring (P = 0.04). There was no significant reduction in the incidence of trigeminal ganglionic latency in the vaccinated rabbits (P greater than 0.05). Thus, our results indicate that V52, a gD recombinant vaccine probably is safe with regard to corneal scarring, and may provide a small amount of protection against ocular HSV-1 infection. The amount of protection provided was less than that reported in mice and guinea pigs. This suggests that to provide high levels of ocular protection in rabbits (and probably in humans), HSV-1 vaccines may have to elicit a more vigorous immune response than that produced by normal HSV-1 infection.

AN-1792 (Elan).

Elan is developing AN-1792 as a potential immunotherapy for Alzheimer's disease (AD). It is currently in phase I trials [350904]. Phase II/III trials, running in parallel in the US and UK, are expected to start by the end of 2001 [375061], [383226], [401966]. American Home Products (AHP) are collaborating with Elan on research and development of an immunotherapy directed towards the beta-amyloid peptide, including AN-1792 and other potential products [361702]. In September 2000, an agreement was established between Elan, AHP and Cambridge Antibody Technology (CAT), whereby CAT are investigating anti-beta-amyloid human antibodies [394844]. In July 2000, Merrill Lynch predicted a possible late-2001 entry into pivotal trials with a potential NDA filing in 2004 [375966]. The clinical program is expected to take approximately four years [339630]. In April 2001, ABN Amro Hoare Govett stated that, if data from the large phase II trial expected to start late in 2001 satisfied FDA requirements, then Elan might be able to file an NDA in 2003, with a potential launch in 2005 [407412].

Non-clinical vaccine safety assessment.

As vaccines are undoubtedly classified as pharmaceuticals, they have to be submitted to strict non-clinical safety evaluation. The context of their prophylactic use requires that every effort is made to ensure their safe use. Their safety evaluation is complex as they act through a multistage mechanism in which the vaccine by itself acts as a pro-drug, antibodies and activated lymphocytes being the actual effectors. Therefore, several potential toxicities must be considered: direct toxicity of the test article, toxicity linked to the pharmacodynamic activity of the vaccine, activation of pre-existing disorders, toxicity of contaminants and impurities and other adverse reactions due to interaction between the various components. Guidelines dealing with vaccines include general guidelines applicable to all pharmaceuticals, such as ICH S6, and also more specific documents which allow some flexibility in study design. Among the various studies, if single-dose studies are generally part of the quality control test battery, repeated dose studies are pivotal. The animal model and treatment schedule selection and the parameters investigated are critical for the relevance of this safety assessment. Immunological and safety pharmacology parameters should be adapted to the specific properties of vaccines and added to this type of study. Vaccines intended for pregnant women or women of child-bearing age require embryo-fetal and post-natal studies with an adapted design to obtain appropriate fetal and maternal exposure during gestation with continuation into the post-natal period. Tests exist to detect hypersensitivity or autoimmune reactions, but require further validation. In addition to this tailor-made approach, any adjuvant or active component added to the vaccine formulation necessitate their own assessment using studies routinely performed for new drugs. From this review, vaccine toxicology would appear to be a separate discipline on its own whose predictivity will be increased by new method development.

Vaccines: predicting the risk of allergy and autoimmunity.

The field of vaccines is markedly evolving with the introduction and development of many new concepts and formulations, as well as new indications. Based on the current clinical experience, vaccines can be considered safe in most cases. Nevertheless, allergy and, to a lesser extent, autoimmunity have repeatedly been described or suspected as rare adverse consequences of human vaccines. The mechanisms of these adverse reactions are ill-elucidated, if at all. No animal models have been adequately standardized and validated to predict the risk of allergy and autoimmunity associated with vaccines. However, a number of existing models can be considered for use, but need refinement to be applied to vaccine evaluation. Finally, because the preclinical safety evaluation has not received much attention in the past, efforts should be paid to design specific and cost-effective procedures to meet the current expectations.

Reproductive toxicity testing of vaccines.

Vaccines play a major role in the prevention of human birth defects by protecting the pregnant woman from teratogenic or otherwise harmful infections. Until now, it has not been common practice to perform preclinical developmental toxicity tests for new vaccines. Despite the excellent safety record of vaccines, increased attention is now being given to the feasibility of screening new vaccines for developmental hazards in animals before their use in humans. Contrary to previous assumptions, many vaccines are now given to potentially pregnant women. Any new components of the vaccine formulation (adjuvants, excipients, stabilisers, preservatives, etc.) could also be tested for influences on development, although based on past experience the risks are limited by the very low dosages used. The conferred immunity following vaccination lasts for several years. Therefore, the developing conceptus may theoretically be exposed to the induced antibodies and/or sensitised T-cells, even if the pregnant woman was last vaccinated during childhood (particularly if she encounters the antigen during pregnancy through exposure to infection). However, it should be kept in mind that viral or bacterial infections represent a higher risk for a pregnant woman than the potential adverse effects related to vaccination or the associated immune response. Non-clinical safety studies may be employed as an aid for hazard identification. In these studies interactions of the vaccine with the maternal immune system or with the developmental systems of the offspring are considered. Post-natal examinations are necessary to detect all possible manifestations of developmental toxicity, such as effects on the immune system. Species selection for the preclinical studies is based on immunogenicity to the vaccine and the relative timing and rate of transfer of maternal antibodies to the offspring. A single study design is proposed for the pre- and post-natal developmental assessments of vaccines in rodents and rabbits.