Physiological evidence of integrin ‐antibody reactive proteins influencing the innate cellular immune responses of larval Galleria mellonella hemocytes

AbstractLarvalGalleria mellonella (L.) hemocytes form microaggregates in response to stimulation by Gram ‐positive bacteria. Hemocyte adhesion to foreign materials is mediated by the cAMP/ protein kinase A pathway and the β‐subunit of cholera toxin using a cAMP‐independent mechanism. Cholera toxin‐induced microaggregation was inhibited by the integrin inhibitory RGDS peptide, implying integrin s may be part of the mechanism. Based on the types of mammalian integrin‐antibody reactive proteins affecting hemocyte adhesion and bacterial‐induced responses α5, αv, β1, and β3 subunits occurred on both granular cell and plasmatocyte hemocyte subtypes. A fluorescent band representing the binding of rabbit α5‐integrin subunit antibodies occurred between adhering heterotypic hemocytes. The frequency of the bands was increased by cholera toxin. The α5 and β1 rabbit integrin subunit antibodies inhibited removal ofBacillus subtilis (Cohn) from the hemolymphin vivo. A α5β1‐specific synthetic peptide blocker similarly diminished hemocyte function whereas the αvβ3‐specific inhibitory peptide and the corresponding integrin subunit antibodies did not influence nonself hemocyte activities. Western blots revealed several proteins reacting with a given integrin‐antibody subtype. Thus integrin‐antibody reactive proteins (which may include integrins) with pos sible α5 and β1 epitopes modulate immediate hemocyte function. Confocal microscopy established plasmatocyt...

Source: Insect Science - November 20, 2018 Category: Biology Authors: Jason F. Lapointe, Connor D. McCarthy, Gary B. Dunphy, Craig A. Mandato Tags: ORIGINAL ARTICLE Source Type: research