Infection of honey bees with acute bee paralysis virus does not trigger humoral or cellular immune responses

Abstract

We have studied the responses of honey bees at different life stages (Apis mellifera) to controlled infection with acute bee paralysis virus and have identified the haemolymph of infected larvae and adult worker bees as the compartment where massive propagation of ABPV occurs. Insects respond with a broad spectrum of induced innate immune reactions to bacterial infections, whereas defence mechanisms based on RNA interference play a major role in antiviral immunity. In this study, we have determined that honey bee larvae and adult workers do not produce a humoral immune reaction upon artificial infection with ABPV, in contrast to control individuals challenged with Escherichia coli. ABPV-infected bees produced neither elevated levels of specific antimicrobial peptides (AMPs), such as hymenoptaecin and defensin, nor any general antimicrobial activity, as revealed by inhibition-zone assays. Additionally, adult bees did not generate melanised nodules upon ABPV infection, an important cellular immune function activated by bacteria and viruses in some insects. Challenge of bees with both ABPV and E. coli showed that innate humoral and cellular immune reactions are induced in mixed infections, albeit at a reduced level.Electronic supplementary materialThe online version of this article (doi:10.1007/s00705-012-1223-0) contains supplementary material, which is available to authorized users.

Seasonal benefits of a natural propolis envelope to honey bee immunity and colony health

“…However, there is contradictory evidence concerning the role of humoral immunity in combating viral infection. Azzami et al (2012) reported that antimicrobial peptide (e.g. hymenoptaecin and abaecin) expression is not altered upon viral challenge, while a more recent study showed that IAPV infection up-regulates multiple immune signaling pathways in adult bees (Chen et al, 2014).…”

Immunogene and viral transcript dynamics during parasitic Varroa destructor mite infection of developing honey bee (Apis mellifera) pupae

“…No evidence for a negative association between immune gene expression and DWV titers was found, in contrast to an earlier study of adult honey bee workers (Yang and Cox-Foster, 2005), suggesting that an active suppression of DWV by the honey bee immune system is unlikely in this case. Instead, a few immune genes were positively associated with the virus titers (Boncristiani et al, 2013) and most did not show a significant association (Azzami et al, 2012). More research is needed to understand virus interactions with insect immunity (Costa et al, 2009;Flenniken and Andino, 2013).…”

“…Immunogene and viral transcript dynamics during parasitic Varroa destructor mite infection of developing honey bee (Apis mellifera) pupae Ryan D. Kuster, Humberto F. Boncristiani and Olav Rueppell* functioning of the honey bee immune system in response to viral infection is particularly understudied and no response (Azzami et al, 2012), immunosuppression (Nazzi et al, 2012) or upregulation of immunogenes (Boncristiani et al, 2013) has been reported. Honey bees respond to pattern recognition of bacterial and fungal molecules through the rapid expression of antimicrobial peptides.…”

Genetic diversity within honey bee colonies affects pathogen load and relative virus levels in honey bees, Apis mellifera L

“…The fact that the mean abundance of mites, and thus, mite feeding pressure, was similar in GDCs and GSCs suggests differences in the immune responses of individual bees within GDCs and GSCs could also contribute to the observed differences in virus prevalence and concentration. Very little is known about the immune response of honey bees to viruses (Azzami et al 2012). However, bees can maintain viral infections without showing obvious disease symptoms (Bailey et al 1963), suggesting some kind of antiviral mechanisms prevent virus replication.…”