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Immune priming specificity within and across generations reveals the range of pathogens affecting evolution of immunity in an insect
Author(s) -
Dhinaut Julien,
Chogne Ma,
Moret Yannick
Publication year - 2018
Publication title -
journal of animal ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.134
H-Index - 157
eISSN - 1365-2656
pISSN - 0021-8790
DOI - 10.1111/1365-2656.12661
Subject(s) - biology , immune system , immunity , offspring , bacteria , gram negative bacteria , priming (agriculture) , microbiology and biotechnology , pathogenic bacteria , host (biology) , immunology , ecology , escherichia coli , genetics , pregnancy , germination , botany , gene
Many organisms can improve their immune response as a function of their immunological experience or that of their parents. This phenomenon, called immune priming, has likely evolved from repetitive challenges by the same pathogens during the host lifetime or across generation. All pathogens may not expose host to the same probability of re‐infection, and immune priming is expected to evolve from pathogens exposing the host to the greatest probability of re‐infection. Under this hypothesis, the priming response to these pathogens should be specifically more efficient and less costly than to others. We examined the specificity of immune priming within and across generations in the mealworm beetle, T enebrio molitor , by comparing survival of individuals to infection with bacteria according to their own immunological experience or that of their mother with these bacteria. We found that insects primed with Gram‐positive bacteria became highly protected against both Gram‐positive and Gram‐negative bacterial infections, mainly due to an induced persistent antibacterial response, which did not exist in insects primed with Gram‐negative bacteria. Insects primed with Gram‐positive bacteria also exhibited enhanced concentration of haemocytes, but their implication in acquired resistance was not conclusive because of the persistent antibacterial activity in the haemolymph. Offspring maternally primed with Gram‐positive and Gram‐negative bacteria exhibited similarly improved immunity, whatever the bacteria used for the infection. Such maternal protection was costly in the larval development of offspring, but this cost was lower for offspring maternally primed with Gram‐positive bacteria. While T . molitor can develop some levels of primed response to Gram‐negative bacteria, the priming response to Gram‐positive bacteria was more efficient and less costly. We concluded that Gram‐positive bacterial pathogens were of paramount importance in the evolution of immune priming in this insect species.