Haemocytes from Pseudoplusia includens express multiple α and β integrin subunits

• Published in: Insect molecular biology 2003-10, Vol.12 (5), p.441-452
• Main Authors: Lavine, M.D, Strand, M.R
• Format: Article
• Language: English
• Subjects: adhesion receptors; Amino Acid Sequence; amino acid sequences; Animals; Blotting, Northern; cell adhesion; DNA Primers; gene expression regulation; hemocyte adhesion; hemocytes; Hemocytes - immunology; hemocytic encapsulation; immune response; insect granulocytes; insect immunity; Integrin alpha Chains - genetics; Integrin alpha Chains - immunology; Integrin beta Chains - genetics; Integrin beta Chains - immunology; membrane proteins; messenger RNA; Molecular Sequence Data; Moths - genetics; Moths - immunology; nucleotide sequences; Phylogeny; plasmatocytes; Polymerase Chain Reaction; protein subunits; Pseudoplusia includens; receptors; sequence homology; transcription (genetics)
• ISSN: 0962-1075; 1365-2583
• DOI: 10.1046/j.1365-2583.2003.00428.x

Cellular immune responses such as encapsulation involve the adhesion of one or more classes of haemocytes. How insect haemocytes recognize encapsulation targets as foreign or the identity of the molecules regulating haemocyte adhesion is unknown. One of the most important classes of adhesion receptors in mammalian immune cells is the integrins, which form functional heterodimers through different combinations of α and β subunits. Prior studies with the moth Pseudoplusia includens indicated that encapsulation depends on two classes of haemocytes called granulocytes and plasmatocytes. Here we report the cloning and identification of three α integrin subunits (αPi1-3) and one β subunit (βPi1) from P. includens. Northern blot analysis indicated that all four subunits are expressed in granulocytes and that three of the four subunits are expressed in plasmatocytes. Quantification of transcription patterns using real-time PCR revealed that expression of αPi2 and βPi1 increased in granulocytes and plasmatocytes when binding to a foreign surface or forming a capsule. αPi2 transcription in plasmatocytes was further increased by granulocyte conditioned medium, plasmatocyte spreading peptide, and the integrin recognition peptide RGD. Collectively, these results suggest that one or more integrins play an important role in regulating haemocyte adhesion during encapsulation.