The impact of baculovirus challenge on immunity: The effect of dose and time after infection.
J Invertebr Pathol
; 167: 107232, 2019 10.
Article
em En
| MEDLINE
| ID: mdl-31445007
ABSTRACT
Understanding how hosts respond to pathogen attack is crucial to disease management. The response of a host can be particularly important if hosts have to defend against multiple pathogens which could either benefit from or be suppressed by prior pathogen exposure. Insect defence against viruses is less well understood than responses to other entomopathogens and much of the information available relates to in vitro studies and model systems. Baculoviruses are natural pathogens of insects, particularly Lepidoptera, and have been well-studied in terms of their ecology, pest control potential and molecular biology. In order to examine how an insect reacts to baculovirus challenge, we measured components of the cellular and humoral immune response of the cabbage looper Trichoplusia ni to Trichoplusia ni SNPV, a narrow-host range nucleopolyhedrovirus (NPV), over four doses and three times after pathogen challenge (18, 42 and 90â¯h). We found that total haemocyte numbers peaked at 42â¯h post-exposure at all doses, and declined linearly with increasing dose after the 18â¯h time point. Two immune-related enzymes, phenoloxidase (PO) and FAD-glucose dehydrogenase (GLD), showed very different responses. PO levels were lowest at the 42â¯h time point and were not influenced by virus dose when each time point was examined separately. GLD levels declined over time but they interacted with virus dose in a non-linear manner, such that there was an increase in levels at intermediate virus doses after 18â¯h, no effect at 42â¯h, and then declined as infection progressed at 90â¯h post-infection. These data suggest that baculoviruses can rapidly infect haemocytes (or cause a reduction in their numbers) in a dose-dependent manner once the infection is systemic, likely reducing the ability of the host to counter subsequent infections. However, the data do not support a direct role for PO in defence against baculoviruses. Whether GLD plays a role in virus defence is still unclear.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Viroses
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Relação Dose-Resposta Imunológica
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Mariposas
Limite:
Animals
Idioma:
En
Ano de publicação:
2019
Tipo de documento:
Article