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Localized leukocyte response to Ichthyophthirius multifiliis establishment in immune carp Cyprinus carpio L.
Parasrtology Today, vol.
IO,no. .?. I994
I, IS-18 8 Clark, C.G. and Diamond, L.S. Exp. Porasitol. 77 (in press) 9 Chadee, K., Smith, J.M. and Meerovitch, E.
47
( 1985) Am. J, Trap.Med. Hyg, 34, 870-878 IO Vohra, H. et al. (1989) Trans.R. Sot. Trap. Med. Hyg. 83,648-650 I I McMlllan, A. et al. (I 984) Gut 25, 356-360
Localized Leukocyte Response to lchthyophthirius multifiliis Establishment in Immune Carp Cy#winuscorpio L. M.L. Cross and R.A. Matthews Vet Immunol. Immunopathol. 38, 34 I-358 Whitespot is a disease of serious economic importance in intensive f-eshwater finfish aquaculture, and is caused by the ciliate /hthyophthi?‘us multifiliis Fourquet, 1876, which parasitizes the epithelial surfaces of the skin, gills and buccal cavity, resulting in severe localized skin pathogenesis. Fish that survive a low-level primary exposure can become resistant to re-infection, and this protection is thought to be humorally mediated. The skin of fish in a state of non-sterile protective immunity is penetrated by theronts; rather than be killed in situ by the host serum response, protection is directed against parasites exiting the skin within two hours of entry. There has never been a detailed analysis of the types of cell involved in the mediation of host pathogenesis and of their effects on parasites developing within the epithelia, both in immunized fish and in those experiencing a primaty
infection. Cross and Matthews focus on the caudal fin epidermis of O-group carp to study this problem. In both groups, there is a rapid (I -2 days post-infection) infiltration of neutrophils to the infection site, representing a nonspecific inflammatotytype reaction. In both groups, polymorphonuclear leukocytes predominated in the later stages (3-7 days), suggesting cellular responses, which differed from normal inflammatory reactions. In primary infections, the later stage was characterized by a predominance of eosinophils and basophils, possibly in response to chemoattractive factors. Localized cellular infiltration was also seen in response to trophozoites established in immune fish, characterized by a predominance of eosinophilia granular cells (EGCs), and, to a lesser degree, basophils. EGCs are likened to mast cells in mammals, and have been
Acetylcholinesterase in Infective-stage Larvae of Haemonchus contortus, Ostereogia circumcincto and Trichostrongylus colubriformis Resistant and Susceptible to Benzimidazole Anthelmintics I.A. Sutherland and D.L. Lee Parasitology 107, 553-557 The mode of action of the resistance of benzimidazole (BZ) in nematodes has been well reviewed, and is known to be associated with reduced binding of BZ to tubulin. It has also been established that there is more nonspecific esterase activity in resistant than in nonresistant strains of Haemonchus contortus, Ostertogia circumcincta and Trichostrongybs colubtiformis. In this paper, a calorimetric assay (Fmol acetylthiocholine iodide X IO-5 hydrolysed per IO0 pg total protein per hour at 37°C) is used to quantify the clifference in acetylcholinesterase (AChE) content between infective (3rd~stage) larvae of BZ-resistant and BZ-susceptible strains of these nematodes. In each case, the resistant strains had higher levels of AChE activity than did the susceptible strains. This ipositive correlation between higher levels of enzyme activity and resistance to BZs is 0
,994. Eisewer kence
Ltd
puzzling, as BZs act against neither AChE nor its receptor. Therefore, this observation must be unrelated to the mode of action of BZ. However, organelles in resistant strains may simply secrete more enzymes, including AChE, in response to disturbed tubulin levels, and these enzymes may in turn play a part in resistance. One possibility is that the extra enzymes serve to detoxify the BZ by altering its active site. There is evidence that elevated levels of AChE may be associated with resistance to both levamisole and morantel tartrate in 0. circumcincta and in T. colubriformis, again suggesting its importance as an unspecific anthelmintic-detoxifying or -evading mechanism in these nematodes. 4
Outlook was compiled by T. Saklatvala.
C. Graham Clark and LOUIS5. Diamond are at the Laboratory of Parawtrc Diseases, N/A/D. Nationa/ Institutes of Health, Bethesda, MD 20892, USA.
shown to infiltrate fish tissues in response to helminth and ectoparasitic crustacea infection. The presence of EGCs also suggests the presence of a specific immune component. Leukocytes are observed in close proximity to the parasite surface in both groups of fish, but there is no evidence of cell adherence. They are present within the layers of necrotic tissue debris surrounding the parasite, but the absence of parasite damage suggests that they do not perform any direct antiparasite function. Phagocytosis by neutrophils, macrophages and epidermal filament cells is more extensive on the skin of immunized fish than on that of first-exposed fish possibly invoking a mechanism involving immune complex uptake. The nature of the specific component is unknown, and may reflect a cellular function unique to immune fish. While cellular phagocytic responses do not seem to cause damage to parasites that exist in immune fish, they may play a role in mediating protective responses. w
Meetings If you are organizing a meeting that is of interest to parasitologists, please supply Parasitology Today with the details (dates, title, location) and a contact name (at least 8-10 weeks prior to the meeting dates), and we will include your meeting in our Diary page, without charge. If you are attending such a meeting, perhaps you would like to consider writing a short report of the meeting, capturing its main messages and the future directions indicated for the topic. Please contact: The Editor, ParasitologyToday, Elsevier Trends Journals, 68 Hills Road, Cambridge, UK CB2 ILA.
IO,no. .?. I994
I, IS-18 8 Clark, C.G. and Diamond, L.S. Exp. Porasitol. 77 (in press) 9 Chadee, K., Smith, J.M. and Meerovitch, E.
47
( 1985) Am. J, Trap.Med. Hyg, 34, 870-878 IO Vohra, H. et al. (1989) Trans.R. Sot. Trap. Med. Hyg. 83,648-650 I I McMlllan, A. et al. (I 984) Gut 25, 356-360
Localized Leukocyte Response to lchthyophthirius multifiliis Establishment in Immune Carp Cy#winuscorpio L. M.L. Cross and R.A. Matthews Vet Immunol. Immunopathol. 38, 34 I-358 Whitespot is a disease of serious economic importance in intensive f-eshwater finfish aquaculture, and is caused by the ciliate /hthyophthi?‘us multifiliis Fourquet, 1876, which parasitizes the epithelial surfaces of the skin, gills and buccal cavity, resulting in severe localized skin pathogenesis. Fish that survive a low-level primary exposure can become resistant to re-infection, and this protection is thought to be humorally mediated. The skin of fish in a state of non-sterile protective immunity is penetrated by theronts; rather than be killed in situ by the host serum response, protection is directed against parasites exiting the skin within two hours of entry. There has never been a detailed analysis of the types of cell involved in the mediation of host pathogenesis and of their effects on parasites developing within the epithelia, both in immunized fish and in those experiencing a primaty
infection. Cross and Matthews focus on the caudal fin epidermis of O-group carp to study this problem. In both groups, there is a rapid (I -2 days post-infection) infiltration of neutrophils to the infection site, representing a nonspecific inflammatotytype reaction. In both groups, polymorphonuclear leukocytes predominated in the later stages (3-7 days), suggesting cellular responses, which differed from normal inflammatory reactions. In primary infections, the later stage was characterized by a predominance of eosinophils and basophils, possibly in response to chemoattractive factors. Localized cellular infiltration was also seen in response to trophozoites established in immune fish, characterized by a predominance of eosinophilia granular cells (EGCs), and, to a lesser degree, basophils. EGCs are likened to mast cells in mammals, and have been
Acetylcholinesterase in Infective-stage Larvae of Haemonchus contortus, Ostereogia circumcincto and Trichostrongylus colubriformis Resistant and Susceptible to Benzimidazole Anthelmintics I.A. Sutherland and D.L. Lee Parasitology 107, 553-557 The mode of action of the resistance of benzimidazole (BZ) in nematodes has been well reviewed, and is known to be associated with reduced binding of BZ to tubulin. It has also been established that there is more nonspecific esterase activity in resistant than in nonresistant strains of Haemonchus contortus, Ostertogia circumcincta and Trichostrongybs colubtiformis. In this paper, a calorimetric assay (Fmol acetylthiocholine iodide X IO-5 hydrolysed per IO0 pg total protein per hour at 37°C) is used to quantify the clifference in acetylcholinesterase (AChE) content between infective (3rd~stage) larvae of BZ-resistant and BZ-susceptible strains of these nematodes. In each case, the resistant strains had higher levels of AChE activity than did the susceptible strains. This ipositive correlation between higher levels of enzyme activity and resistance to BZs is 0
,994. Eisewer kence
Ltd
puzzling, as BZs act against neither AChE nor its receptor. Therefore, this observation must be unrelated to the mode of action of BZ. However, organelles in resistant strains may simply secrete more enzymes, including AChE, in response to disturbed tubulin levels, and these enzymes may in turn play a part in resistance. One possibility is that the extra enzymes serve to detoxify the BZ by altering its active site. There is evidence that elevated levels of AChE may be associated with resistance to both levamisole and morantel tartrate in 0. circumcincta and in T. colubriformis, again suggesting its importance as an unspecific anthelmintic-detoxifying or -evading mechanism in these nematodes. 4
Outlook was compiled by T. Saklatvala.
C. Graham Clark and LOUIS5. Diamond are at the Laboratory of Parawtrc Diseases, N/A/D. Nationa/ Institutes of Health, Bethesda, MD 20892, USA.
shown to infiltrate fish tissues in response to helminth and ectoparasitic crustacea infection. The presence of EGCs also suggests the presence of a specific immune component. Leukocytes are observed in close proximity to the parasite surface in both groups of fish, but there is no evidence of cell adherence. They are present within the layers of necrotic tissue debris surrounding the parasite, but the absence of parasite damage suggests that they do not perform any direct antiparasite function. Phagocytosis by neutrophils, macrophages and epidermal filament cells is more extensive on the skin of immunized fish than on that of first-exposed fish possibly invoking a mechanism involving immune complex uptake. The nature of the specific component is unknown, and may reflect a cellular function unique to immune fish. While cellular phagocytic responses do not seem to cause damage to parasites that exist in immune fish, they may play a role in mediating protective responses. w
Meetings If you are organizing a meeting that is of interest to parasitologists, please supply Parasitology Today with the details (dates, title, location) and a contact name (at least 8-10 weeks prior to the meeting dates), and we will include your meeting in our Diary page, without charge. If you are attending such a meeting, perhaps you would like to consider writing a short report of the meeting, capturing its main messages and the future directions indicated for the topic. Please contact: The Editor, ParasitologyToday, Elsevier Trends Journals, 68 Hills Road, Cambridge, UK CB2 ILA.