[Show abstract][Hide abstract] ABSTRACT: Five-month-old beagle dogs were experimentally infected with amastigotes of Leishmania infantum and kept for 14 months. Infection course was monitored by clinical examination, serum protein variations, and levels of specific antibodies against Leishmania estimated by indirect immunofluorescence test and Western blotting (WB). Infected animals developed notable changes in serum protein levels reaching maximum protein concentrations 2-3 months postinfection (p.i.) related to the gamma-globulin fraction. Specific antibody titers were in good agreement with the serum protein rise, reaching immunofluorescence values of over 1:800 3 months p.i. Serial Western blotting analysis with L. infantum promastigotes protein showed a strong response against immunodominant antigens of 50-57, 42, and 29 kDa during most of the studied period with immunofluorescence titers of over 1:100 and in addition the response was remarkably homogeneous among the infected dogs. Immunoreactivity patterns displayed time-related variations; the response against 29 and 50-57 kDa was seen very early, followed by the reaction around 42, 76, and 86 kDa. In addition the recognition of peptides around 34-35.4 and 26 kDa was restricted to the acute phase of the experimental infection. Preliminary results obtained in naturally infected dogs seem to support the predictive value of the WB.
[Show abstract][Hide abstract] ABSTRACT: A preliminary trial on the extent of cross-antigenicity among the sheep strongylids Haemonchus contortus, Trichostrongylus colubriformis, Teladorsagia circumcincta and Nematodirus battus in 2.5- to 4-month-old lambs has been carried out using ELISA and Western blotting (WB). Cross antigenicity was tested using soluble extracts from adult and third stage larvae (L3) of H. contortus as antigenic source probed with sera from lambs with monospecific heterologous infections. There was cross-antigenicity between L3 of H. contortus and Trichostrongylus colubriformis in ELISA and WB. Immunodetection results with adult H. contortus antigen showed a closer relationship to Teladorsagia circumcincta. Certain heterologous sera reacted with H. contortus antigens more strongly than the homologous one, but sera from the H. contortus-infected animals had reactivity around the 25 kDa region from adult antigens which could have potential diagnostic use.
[Show abstract][Hide abstract] ABSTRACT: Two isolates (skin and lymph node) of Leishmania infantum obtained from a naturally infected dog were cloned and the free pools of polyamines for both complete isolates and clones were determined. Putrescine (Put) and spermidine (Spd) levels were highly variable among the lines studied, ranging from 0.89 to 2.1 nmol Spd/10(7) promastigotes. The Put/Spd ratio was also variable (1.54-0.51) and correlated with the cell growth of the lines studied. There were important differences in the clones' sensitivities to difluoromethylornithine (DFMO) and Berenil, with some of the clones being almost refractory to the inhibitory effect of 50 microM DFMO, whereas the growth of others was reduced by 60%; similar findings were obtained with 50 microM Berenil. L. infantum sensitivities to DFMO and Berenil were correlated and apparently related to the values for the Put/Spd index.
Parasitology Research 02/1994; 80(3):203-7. DOI:10.1007/BF00932675 · 2.10 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Sixteen- to eighteen-week-old lambs were infected with 2500 3rd stage larvae (L-3) of Haemonchus contortus or kept as uninfected controls. Two months later all animals were challenged with 5000 L-3 of this parasite. Soluble antigens of H. contortus L-3 and adult worms were analyzed by SDS-PAGE and Western blotting during experimental infection and challenge. Antigens from both sources, particularly of low molecular weight under reducing conditions, were recognised by the pooled sera of infected lambs. No single L-3 antigen was recognised by all infected lambs, whereas two peptides having around 25 and 26 kDa from adults were recognised by infected animals during the patency and could be of potential use in the diagnosis of lamb haemonchosis.
[Show abstract][Hide abstract] ABSTRACT: Seven-week-old female kids of the Murciana-Granadina breed naturally infected with coccidia were superinfected with a multispecific Eimeria inoculum (300,000 oocysts) or treated to control the coccidial infection with Amprolium (50 mg kg-1 liveweight day-1; 4 days every 14 days); 80 days later both animal groups received 2500 third-stage larvae of a sheep-derived mixture of Trichostrongylus colubriformis (50%), Teladorsagia circumcincta (40%) and Haemonchus contortus (10%). Kids experimentally superinfected with Eimeria showed reduced food intake at the early patency period, higher numbers of oocysts passed at weaning time and lower liveweight gain than the Amprolium-medicated kids. In the Eimeria superinfected kids the trichostrongyle infection caused a tendency to result in chronic coccidial infections. Further, these animals had higher numbers of nematode eggs in their faeces, lower dressed weights on slaughter and inferior meat quality.