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Within-host models describe the dynamics of immune cells when encountering a pathogen, and how these dynamics can lead to an individual-specific immune response. This systematic review aims to summarize which within-host methodology has been used to study and quantify antibody kinetics after infection or vaccination. In particular, we focus on data-driven and theory-driven mechanistic models. PubMed and Web of Science databases were used to identify eligible papers published until May 2022. Eligible publications included those studying mathematical models that measure antibody kinetics as the primary outcome (ranging from phenomenological to mechanistic models). We identified 78 eligible publications, of which 8 relied on an Ordinary Differential Equations (ODEs)-based modelling approach to describe antibody kinetics after vaccination, and 12 studies used such models in the context of humoral immunity induced by natural infection. Mechanistic modeling studies were summarized in terms of type of study, sample size, measurements collected, antibody half-life, compartments and parameters included, inferential or analytical method, and model selection. Despite the importance of investigating antibody kinetics and underlying mechanisms of (waning of) the humoral immunity, few publications explicitly account for this in a mathematical model. In particular, most research focuses on phenomenological rather than mechanistic models. The limited information on the age groups or other risk factors that might impact antibody kinetics, as well as a lack of experimental or observational data remain important concerns regarding the interpretation of mathematical modeling results. We reviewed the similarities between the kinetics following vaccination and infection, emphasising that it may be worth translating some features from one setting to another. However, we also stress that some biological mechanisms need to be distinguished. We found that data-driven mechanistic models tend to be more simplistic, and theory-driven approaches lack representative data to validate model results. [ABSTRACT FROM AUTHOR]

• Insect cells can be used to produce viable Virus-like particles (VLPs) based on OaPV3 L1. • VLPs-based ELISA allowed investigating natural immune response to OaPV3 infection. • Anti-VLPs antibodies are useful tools for OaPV3 in situ detection. • OaPV3 VLPs are suitable candidates for the development of prophylactic vaccines. The design of prophylactic and diagnostic tools specific to animal papillomaviruses is hampered by the difficulties of viral in vitro manipulation and by the scarce availability of dedicated biotechnological tools. This paper reports the production of Ovine Papillomavirus 3 (OaPV3)-based virus-like particles (OaPV3-VLPs) in the baculovirus system and their use to investigate host humoral immune response through the establishment of an indirect ELISA test., Polyclonal sera and monoclonal antibodies were generated against OaPV3-VLPs, and their isotype and reactivity were determined. Additionally, antibodies allowed OaPV3 detection in ovine squamous cell carcinoma (SCC) samples by immunohistochemistry. Results encourage the standardization of OaPV3-specific prophylactic and serological diagnostic tools, and open new perspectives for the study of host-viral interaction and SCC development. [ABSTRACT FROM AUTHOR]

Vaccines against bovine babesiosis must, ideally, induce a humoral immune response characterized by neutralizing antibodies against conserved epitopes and a cellular Th1 immune response. In Babesia bovis , proteins such as AMA-1, MSA-2c, and RAP-1 have been characterized and antibodies against these proteins have shown a neutralizing effect, demonstrating the implication of B and T-cell epitopes in the immune response. There is evidence of the existence of B and T-cell epitopes in these proteins, however, it remains to be defined, the presence of conserved peptides in strains from around the world containing B and T-cell epitopes, and their role in the generation of a long-lasting immunity. The aim in this paper was to identify peptides of Babesia bovis AMA-1, MSA-2c, and RAP-1 that elicit a neutralizing and long-lasting Th1 immune response. Peptides containing B-cell epitopes of AMA-1, MSA-2c and RAP-1, were identified. The immune response generated by each peptide was characterized in cattle. All peptides tested induced antibodies that recognized intraerythrocytic parasites, however, only 5 peptides generated neutralizing antibodies in vitro : P2AMA-1 (6.28%), P3MSA-2c (10.27%), P4MSA-2c (10.42%), P1RAP-1 (32.45%), and P4RAP-1 (36.98%). When these neutralizing antibodies were evaluated as a pool, the inhibition percentage of invasion increased to 52.37%. When the T cellular response was evaluated, two peptides: P3MSA2c and P2AMA1 induced a higher percentage (>70%) of activated CD4 +/CD45RO+ T cells than unstimulated cells. Additionally, both peptides induced the production of gamma interferon (IFN−) in PBMCs from vaccinated cattle after one year proving the implication of a long-lasting Th1 immune response. In conclusion, we identified conserved peptides containing B and T-cell epitopes in antigens of B. bovis that elicit a Th1 immune response and showed evidence that peptides from the same protein elicit different immune responses, which has implication for vaccine development in bovine babesiosis. [ABSTRACT FROM AUTHOR]