Innate immunity

Immune system has evolved to protect us against diseases. Innate defences are of special interest, as its effectiveness defines often the fate of the encounter with pathogens. It is crucial to understand, how the innate immune responses are shaped and enhanced by environment, as well as by parental experiences. Insects pose excellent models to study the evolution as well as mechanisms behind the immunity. The lack of antibodies in the insects led to long time belief, that the immunity in insects has no adaptive features – this has been found to be not true. It has been demonstrated that immune priming is also possible by other means. Here we study the mechanism, both physiological as well as behavioural, which lead to more resistant phenotype.

ESB bees

 

Transgenerational immune priming – vaccination a’la honeybees

Historically, vaccination of beneficial insects, such as honey bees, was deemed unfeasible since these animals lack antibody-based, acquired immune system. Yet, a breakthrough by us in understanding immune priming in honey bees indicates that vaccination can occur via the mother insect, the queen (Salmela et al., 2015). This antibody independent immune priming mechanism has allowed us to start developing a vaccination program for honey bees. Vaccination effort in pollinators is a completely novel, unprecedented task, as there are no current or former vaccines available for insects. We have selected P. larvae as the first pathogen target for vaccine development due to its significant contribution to the global decline of bees. P. larvae attacks only newly hatched bee larvae, whereas older individuals are immune to it, but serve as vectors. The pathology and infection time makes it extremely hard to fight against American foulbrood. Most efficient way to target the infection would be enhancing the resistance in early larval stages. This is exactly the approach of our vaccination method.

Self-medication in ants

One way to fight diseases is self-medication, which occurs when an organism consumes biologically active compounds to clear, inhibit, or alleviate disease symptoms. This type of behavioral defense mechanism can be crucial in fight against the pathogens and make a big impact on the outcome of host-parasite interaction. Understanding how self-medication is triggered on the physiological level, translated into behavioral response, which leads to further physiological changes via altered diet is challenging but fascinating area of research. We have shown for the first time that ants selectively consume harmful substances upon exposure to a fungal pathogen, yet avoid these in the absence of infection (Bos et al., 2015). Our next step is to investigate self-medication behavior in the more natural setting, by recreating multitrophic interactions in the semi-artificial conditions in the lab.

People involved:

Dalial Freitak

Franziska Dickel - Post-doctoral researcher - honeybees

Matti Leponiemi – PhD student – honeybees

Jason Rissanen – master student – ants