An experimental model for canine visceral leishmaniasis

Seven mixed-breed dogs were challenged with either promastigotes or amastigotes of Leishmania donovani infantum strains recently isolated from naturally infected dogs. Different routes and numbers of parasites were utilized and each dog was monitored for at least 1 year post-infection. Anti-parasite specific antibody levels were measured by enzyme-linked immunosorbence, immunofluorescence, crossed-immune electrophoresis and Western blotting on crude antigen. Western blotting on two pure parasite proteins, dp72 and gp70-2, was also done. Mitogenic and antigen-specific stimulation of peripheral blood lymphocytes was monitored; and the haematological, clinical and parasitological parameters measured. Dogs challenged with amastigotes exhibited a more pronounced humoral response to leishmanial antigens. Only in one case was strong antigen-specific proliferation detected. Clinical signs of disease, including hypergammaglobulinaemia, enlarged lymph nodes and the presence of parasites, were also more apparent in the dogs challenged with amastigotes. None of the seven dogs died. Serum antibodies to leishmanial antigens were apparent between 1.5 to 3 months following challenge and correlated with the appearance of enlarged lymph nodes, hypergammaglobulinaemia and the presence of parasites in tissue biopsies. Serum antibodies remained chronically high in these dogs throughout the period of the study. Only one dog (1/3) challenged intravenously with promastigotes and the dog challenged intradermally with amastigotes produced transient antibody responses to leishmanial antigen.     

Positive skin tests to pollen extracts of four species of Pistacia in Israel

Fifty-eight atopic and nine non-atopic volunteers, all residents of the Tel Aviv metropolitan area. Israel, were skin tested with extracts made from filtered pollen of Pistacia atlantica, P. lentiscus, P. palaestina and P. vera. Twenty-four out of the fifty-eight patients examined (41.4% had positive skin reactions to at least one of the four examined species of Pistacia : seven of the patients reacted to all the examined extracts, whereas the other seventeen reacted to only some of them. Fifteen patients reacted to extracts of P. atlantica , sixteen patients reacted to extracts of P. lentiscus , ten patients reacted to extracts of P. palaestina and seven patients reacted to extracts of pollen of P. vera. None of the healthy, non-atopic volunteers reacted to any of the extracts. To the best of our knowledge, this is the first report of immunological reactions to pollen extracts of the genus Pistacia.