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  • 1
    Electronic Resource
    Electronic Resource
    Discriminative ability and function of the immunobiological recognition system of the snailHelix pomatia (1981)
    Springer
    Journal of comparative physiology 141 (1981), S. 477-488 
    Details
    ISSN: 1432-136X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The internal defense mechanism ofHelix pomatia discriminates between different types of foreign cells as demonstrated by determinations of their clearance rates. The rate of elimination is not dependent on the size of foreign cells but on their molecular surface properties. Circulating hemocytes are not involved in the first phase of the clearance event, which is characterized by an accumulation of nonself cells in the digestive gland, kidney and foot muscle ofHelix. Light microscopic studies of these organs reveal nonself cells to be attached to the membrane of cells lining hemolymph sinuses. The attachment of certain types of foreign cells is apparently mediated by opsonins as their clearance depends on the opsonin level of the hemolymph, whereas others are cleared without involvement of opsonizing molecules. Membrane bound molecules of the latter type of nonself cells seem to directly interact with carbohydrate-specific combining sites on the membranes of cells of the sinus walls, as their binding can be inhibited by N-acetyl-galactosamine, and N-acetyl-glucosamine. The second phase of clearance apparently involves the attraction of circulating hemocytes by organtrapped foreign cells. The number of hemocytes in circulation decreases significantly, whereafter a rising percentage of hemocytes containing foreign cells can be observed in the circulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01101470
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  • 2
    Electronic Resource
    Electronic Resource
    Opsonizing properties of an isolated hemolymph agglutinin and demonstration of lectin-like recognition molecules at the surface of hemocytes fromMytilus edulis (1983)
    Springer
    Journal of comparative physiology 149 (1983), S. 535-546 
    Details
    ISSN: 1432-136X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Mytilus hemolymph was found to contain an agglutinin which could be inhibited by mucin. The agglutinin was isolated by affinity chromatography using neuraminidase-treated mucin/Sepharose. In vitro phagocytosis experiments revealed that only about 5% of washed hemocytes phagocytosed yeast cells suspended in a Tris-buffered NaCl-solution, whereas yeast suspended in hemolymph was normally ingested by more than 50% of the hemocytes. This relatively high phagocytic activity was shown to depend on the presence of two serum factors: When purified agglutinin was added to saline-suspended yeast, phagocytosis rates returned to normal, demonstrating opsonizing properties of the purified agglutinin. — On the other hand, addition of Ca++-ions to saline caused an increase of the phagocytic activity of hemocytes. This was interpreted to indicate the activation of divalent cation-dependent recognition molecules at the hemocyte surface. The function of these postulated recognition factors was demonstrated by phagocytosis inhibition tests. Their location at the hemocyte membrane became evident by binding of specific antiagglutinin IgG purified by help of an agglutinin/Sepharose column from an antiserum raised againstMytilus serum proteins. Consequently, humoral as well as cell bound agglutinin molecules are involved in the attachment of yeast cells toMytilus hemocytes which subsequently internalize foreign cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00690013
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Two lectins on the surface of Helix pomatia haemocytes: a Ca2+-dependent, GalNac-specific lectin and a Ca2+-independent, mannose 6-phosphate-specific lectin which recognises activated homologous opsonins (1991)
    Springer
    Journal of comparative physiology 161 (1991), S. 43-54 
    Details
    ISSN: 1432-136X
    Keywords: Helix pomatia ; Lectin ; Opsonin ; Mannose-6-phosphate ; Immunorecognition ; Receptors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Haemocytes of the gastropod mollusc, Helix pomatia, possess on their surface a membrane-integrated GalNac-specific lectin which binds to and stimulates phagocytosis of GalNac-bearing target cells (human A erythrocytes) only in the presence of extracellular calcium ions. Target cells without GalNac moieties on their surface (human B and bovine erythrocytes) are not recognised. Helix haemocytes also possess a Ca2+-independent mannose-6-phosphate-specific lectin on their surface which, in the absence of extracellular calcium ions, enables recognition and phagocytosis of A rbc opsonised with agglutinins isolated from either the snail's albumin gland or serum. These opsonins, however, bind to host haemocytes only after binding to GalNac moieties on the surface of test particles. Our results indicate that such a ligand-specific opsonin/target cell interaction apparently induces a conformational change in the opsonin, resulting in exposure of mannose 6-phosphate moieties that are recognised by the Ca2+-independent lectin on the surface of the haemocytes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00258745
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  • 4
    Electronic Resource
    Electronic Resource
    The binding of lectins to carbohydrate moieties on haemocytes of the insects, Blaberus craniifer (Dictyoptera) and Extatosoma tiaratum (Phasmida) (1989)
    Springer
    Cell & tissue research 257 (1989), S. 445-454 
    Details
    ISSN: 1432-0878
    Keywords: Lectin-labelling ; Haemocyte receptors ; Extatosoma tiaratum ; Blaberus craniifer (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The specificity and distribution of carbohydrate moieties, which act as receptors for lectins on the haemocytes of two insect species, Blaberus craniifer and Extatosoma tiaratum, were investigated. Four peroxidase-labelled lectins were utilised as probes: wheat-germ agglutinin, Ricinus communis (120) agglutinin, concanavalin A and Lens culinaris agglutinin, and binding visualised by reaction with DAB/H2O2. The lectin-binding studies indicated that Blaberus and Extatosoma plasmatocytes, and Extatosoma spreading granular cells possess surface N-acetyl-D-glucosamine, D-galactose and mannose moieties; Extatosoma cystocytes have D-galactose and mannose; whilst Blaberus granular cells/cystocytes and Extatosoma fine granular cells have mannose determinants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00261847
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    Paper (German National Licenses)
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