Setting New Immunobiological Parameters in the Hamster Model of Visceral Leishmaniasis for In Vivo Testing of Antileishmanial Compounds

• Published in: Veterinary research communications Vol. 31; no. 6; pp. 703 - 717
• Main Authors: Dea-Ayuela, M. A, Rama-Íñiguez, S, Alunda, J. M, Bolás-Fernandez, F
• Format: Journal Article
• Language: English
• Published: Netherlands Dordrecht : Kluwer Academic Publishers 01-08-2007; Springer Nature B.V
• Subjects: animal diseases; animal models; Animals; Antibodies, Protozoan - blood; antibody detection; Antigens, CD19 - immunology; antiprotozoal agents; CD4 Antigens - immunology; cell-mediated immunity; Cricetinae; disease course; Disease Models, Animal; dosage; drug evaluation; Enzyme-Linked Immunosorbent Assay; Female; Flow Cytometry; golden hamsters; in vivo studies; inoculum; Leishmania infantum; Leishmania infantum - immunology; Leishmaniasis, Visceral - blood; Leishmaniasis, Visceral - immunology; Leishmaniasis, Visceral - parasitology; liver; Liver - immunology; Liver - parasitology; Lymphocyte Activation; Mesocricetus; microbial detection; microbial load; Organ Size; pathogenesis; promastigotes; signs and symptoms (animals and humans); spleen; Spleen - immunology; Spleen - parasitology; visceral leishmaniasis
• ISSN: 0165-7380; 1573-7446
• DOI: 10.1007/s11259-007-0040-5

To establish suitable immunobiological parameters for in vivo testing of new antileishmanial compounds in the golden hamster model of visceral leishmaniasis, two groups of 8 animals were infected each with 10⁵ or 10⁷ stationary promastigotes by the intracardiac route and the clinical and immunoparasitological features were monitored up to day 155 after infection. All animals became infected at both doses, although significant differences were observed between parasite burdens in liver and spleen. The mean number of parasites in animals infected with 10⁷ promastigotes increased by 9.5 times in liver and by 43.1 times in spleen compared with those infected with 10⁵ promastigotes. In animals given the higher dose, the outcome of the disease occurred between days 75 and 90 after infection, whereas no signs of disease were apparent in those given the lower infecting dose. Positive antibody (IgG) responses were detected earlier (week 5-7 after infection) in animals infected with the higher dose than in those infected with the lower dose (week 8-10 after infection), but these responses did not correlate with individual parasitological loads in liver and spleen. An inverse correlation was observed between infecting doses and in vitro spleen lymphocyte proliferation against mitogens (ConA). The proportion of CD4⁺ and CD19⁺ spleen cell increased in animals given the higher infection, whereas it decreased in those given the lower infection compared to naive controls.