Large foreign bodies such as protozoa, nematodes, eggs, and larvae of parasitic insects are too large for haemocytes to phagocytose. Instead, a process called encapsulation occurs in which a capsule of overlapping layers of cells is formed around the object within 30 min of entry of the pathogen (Bowman & Hultmark, 1987). The encapsulation process initially involves the attachment of granular cells to the target. These granulocytes release plasmatocyte-spreading peptides (PSP) (Vilmos & Kurucz, 1998), which recruit plasmatocytes to the site of capsule formation. Plasmatocytes then bind to the layered granulocytes of the capsule. Choi et al. (2002) identified a G. mellonella protein with amino acid sequence homology to human and Drosophila calreticulin, which was enriched in the early stages of encapsulation. Interestingly, calreticulin has recently been reported to partially localise on the surface of neutrophils, and antimicrobial bound calreticulin was observed to transmit a signal to cells via G-protein to activate neutrophils to generate superoxide anion (Cho et al., 1999). The enrichment of calreticulin seen in G. mellonella capsules may have similar implications to the localisation of human calreticulin on the surface of neutrophils, in that enrichment of calreticulin in haemocytes could potentially activate haemocytes to generate ROS within the capsule.

Cure Your Yeast Infection For Good

Cure Your Yeast Infection For Good

The term vaginitis is one that is applied to any inflammation or infection of the vagina, and there are many different conditions that are categorized together under this ‘broad’ heading, including bacterial vaginosis, trichomoniasis and non-infectious vaginitis.

Get My Free Ebook

Post a comment