3Rs implementation in veterinary vaccine batch-release testing: Current state-of-the-art and future opportunities. A webinar and workshop report

Regulatory authorities require veterinary batch-release testing to confirm vaccine potency and safety, but these tests have traditionally relied on large numbers of laboratory animals. Advances in vaccine research and development offer increasing opportunities to replace in vivo testing, and some stakeholders have made significant progress in incorporating 3Rs elements in quality control strategies. A three-part event series entitled "3Rs Implementation in Veterinary Vaccine Batch-Release Testing: Current state-of-the-art and future opportunities" was jointly organized by the Animal-Free Safety Assessment Collaboration, HealthforAnimals, and the International Alliance of Biological Standardization. Two webinars and a workshop aimed to outline the state-of-the-art non-animal approaches for veterinary batch-release testing. The events included information on the state of the deletion of obsolete safety testing and the current initiatives implemented by European, North American, and Asian-Pacific stakeholders on 3Rs implementation and regulatory acceptance. The events contributed to a better understanding of the barriers to 3Rs implementation. Participants highlighted the need for open communication, continued collaboration between stakeholders, and international harmonization of regulatory requirements to help accelerate acceptance. Despite the challenges, the countries represented at this three-part event have shared their commitments to advancing the acceptance of alternative methods.

Adenovirus Infection Dramatically Augments Lipopolysaccharide-Induced TNF Production and Sensitizes to Lethal Shock

We observed a remarkable synergism of adenoviruses and LPS in triggering the production of TNF in intact animals. We found that in mice pre-exposed to adenoviruses, LPS injections generated extremely high levels of TNF with altered kinetics. The elevated TNF synthesis stemmed mostly from posttranscriptional up-regulation of TNF production, although transcription of the TNF gene was also induced. Adenoviruses and LPS exhibited a significant but less dramatic synergism in the induction of IL-6, IFN-gamma, and NO. Only marginal changes were detected in the synthesis of a panel of other cytokines. Different serotypes of the virus showed practically identical effects. As deletion mutants lacking indispensable viral genes or UV inactivated virions exhibited similar activities as the infectious, wild-type virus, it seems unlikely that the viral genome plays any significant role in the phenomenon. Published data indicate that other viruses also show some kind of synergism with LPS, although by different cellular mechanisms. T cells and their IFN-gamma production--crucial in the synergism of influenza viruses and LPS--were dispensable in our experiments. We suggest that the phenomenon is probably a general one: an overlap between different molecular mechanisms detecting bacterial and viral pathogens and inducing mediators of nonspecific cell-mediated host defense. The synergism of viruses and LPS (bacteria) could be a concern in medical practice as well as in gene therapy experiments with high doses of recombinant adenoviruses.

Latent immunization to produce high-affinity monoclonal antibodies to progesterone

A simple immunization method to obtain high-affinity monoclonal antibodies to progesterone is described in this article. The method is based on the theory of affinity maturation. A long interval between antigen priming and booster ("latent immunization") permits an undisturbed completion of affinity maturation, resulting in the accumulation of memory B lymphocytes with high-affinity Ig receptors, and consequently, in a higher rate of hybridoma clones producing high-affinity antibody after cell fusion. Antibodies obtained after hyperimmunization and latent immunization are compared in a homologous, direct, competitive ELISA. The average numbers of high-affinity antibodies per fusion were 1.3 and 5.7 in the hyperimmunized and latent immunized groups, respectively. There was no significant difference in the specificities between the two immunization groups.