Understanding interactions between the host, microbes and the environment

The host’s genetic background, physiological state, microbiota, rearing conditions and environment can influence infection development, the intensity of an immune response or the expression of a phenotype.

IERP develops and hosts in vivo models to study these interactions in rodents and fish, combining animal production, in vivo studies, containment and functional phenotyping.

From infectious disease research to an integrated view of the host

Infectious disease research is a longstanding area of expertise at IERP.

The infrastructure’s capabilities support the study of different components of the response to an exposure or intervention:

• infection establishment and progression
• immune responses
• inflammation
• vaccination strategies
• microbiota
• genetic factors
• the impact of nutrition and metabolism
• the effects of environmental factors
• physiological or behavioural consequences

This approach goes beyond the relationship between a pathogen and a disease to consider the broader determinants of the observed phenotype.

Developing or adapting an infection model

Depending on the scientific question, IERP can help use an established model, adapt its experimental conditions or assess the feasibility of a new model.

This assessment considers:

• the species and model
• the biological agent
• exposure conditions
• the required containment level
• the parameters to monitor
• the model’s duration
• assessment criteria and humane endpoints
• the proposed functional phenotyping methods

Projects requiring containment are assessed beforehand to check their compatibility with available capabilities.

→ Design a tailored in vivo study

Studying the host response

Characterising a model involves more than measuring the presence of a microorganism.

Depending on the scientific question, monitoring may include:

• clinical or behavioural changes
• physiological parameters
• immune or inflammatory responses
• changes in a biological signal
• lesions or tissue changes
• welfare-related parameters
• criteria specific to the model under study

Having the functional phenotyping platform within IERP makes it possible to combine the model with complementary measurements when these improve understanding of the host response.

→ Explore functional phenotyping

Microbiota and associated microorganisms

The microbiota is itself part of the host’s biological environment.

Its composition and certain microbial interactions can influence physiology, resistance to infection or the response to an intervention.

IERP capabilities and collaborations have supported questions involving microbiota, nutrition and metabolism in different animal models.

For zebrafish, an SPF area supports the production of germ-free or gnotobiotic animals and work on controlled microbiota. These capabilities can be incorporated into a project subject to feasibility.

Incorporating the environment into the model

Environmental conditions can directly influence an organism’s function and its response to an exposure.

Depending on the species and scientific question, various parameters can therefore become components of the experimental model: temperature, diet, housing conditions, health environment and other abiotic and biotic factors.

This aspect is particularly important for aquaculture models, whose environment is closely linked to their physiology.

The aim is to establish experimental conditions consistent with the scientific question and sufficiently controlled to allow results to be interpreted.

Rodent and fish models

Combining rodent and fish models allows different biological questions to be addressed within one infrastructure.

In rodents, projects may explore infection, inflammation, microbiota, immunity, nutrition, physiology or behaviour.

In fish, models are particularly suited to incorporating interactions between the host, microorganisms and aquatic environmental parameters.

This complementarity does not mean that a project must use several species: each model is selected for its scientific relevance.

From challenge to phenotype

IERP’s integrated organisation links several stages of a project:

Depending on requirements, this continuity can combine breeding, infection studies or other interventions, in vivo procedures, longitudinal monitoring, imaging, behaviour and other functional phenotyping approaches.

Measurements are defined according to the scientific question, rather than technologies being added after the project has been designed.

Expertise documented through publications

The scientific output associated with IERP reflects the diversity of questions addressed within the infrastructure.

Infectious disease research and host–pathogen interactions form the largest domain in the scientific corpus, while many studies also concern:

• microbiota, nutrition and metabolism
• reproduction and development
• genetics and selection
• immunology and inflammation
• physiology and behaviour
• method development and functional phenotyping

→ Explore achievements and publications