FUNCTIONAL MORPHOLOGY OF BLOWFLY CALLIPHORA VICINA HEMOCYTES
T.V. Kind
Department of Entomology, Laboratory of Insect Biopharmacology and Immunology, St. Petersburg State University;
e-mail: tatiana.kind@mail.ru
In the hemolymph of Calliphora seven types of hemocytes were revealed. These are prohemocytes, which are the stem cells, stable and unstable hyaline cells,
thrombocytoids, spindle cells, larval plasmatocytes and plasmatocytes I-IV, which represent sequential stages of one cell line differentiation. During the larval period two distinct
waves of hemocyte differentiation were registered. The margin between them is completion of the crop emptying and beginning of wandering stage. In the feeding and crop emptying
larvae take place rising of hyaline cells, thrombocytoids and hyaline cells amount with parallel growth of their defense function. The second wave of hemogenesis occur in the end of
crop emptying period. It is accompanied by burst of plasmatocyte I production with their subsequent differentiation to plasmatocytes II-IV. Production of stable hyaline cells and
respectively prothrombocytoids may be regulated not only by hormonal background but also by inorganic or organic particles invaded into the hemocel. Three types of hemocytes are
involved in loosing of hemolymph from alien particles, notably thrombocytoids, juvenile plasmatocytes and plasmatocytes I and II. Thrombocytoids are responsible for parasitic eggs
encapsulation. In addition they can phagocytize tiny organic and inorganic particles. Juvenile plasmatocytes respond to alien invasion almost as quickly as thrombocytoids at the onset
of invasion. Plasmatocytes I and II start phagocytosis more slowly, hours post invasion, frequently accumulating the particles previously catched by thrombocytoids. Plasmatocytes I
can absorb foreign particles and group in morules and can also surround filled thrombocytoids forming distinctive capsules. Both morules and capsules are temporary structures and
disintegrate some hours lately. It is supposed the existence of three levels of immune defence: the fast response reaction of thrombocytoids and juvenile plasmatocytes and slow cellular
reactions of plasmatocytes I. They are prerequisites for more extensivhumoral response.
Key words: Calliphora vicina, defence reaction, hemocytes, phagocytosis, incapsulation, recognition
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