title: Attenuation parameters for Junin virus in the newborn rat.
abstract: To characterize a virus strain as attenuated, both biologic and biochemical criteria are necessary. In the case of Junin virus, the 2-day-old rat has proved to be a biologic attenuation marker as regards mortality. Here we studied the behaviour of the prototype XJ vs the attenuated XJC13 strain inoculated by either ic or ip route to determine differential hematologic and splenic parameters. Humoral immune response against SRBC was also investigated. By either route XJ caused significant leucocytosis, while the other hematologic parameters remained unchanged. No alterations were found following XJC13 infection. XJ produced significant splenomegaly whereas XJC13 had no effect. Similarly PFC anti-SRBC count was decreased during XJ infection but not after XJC13 infection. These differences between the pathogenic XJ and the attenuated XJC13 strain may be attributed to the former's greater spread. The drop in PFC could be due to spleen dysfunction and/or viral effects on the cell subpopulation involved.
authors.affiliation: Cátedra de Microbiología, Parasitología e Inmunoloogía, Facultad de Medicina, Universidad de Buenos Aires, Argentina.
authors.forename: M C
authors.initials: MC
authors.lastname: Remesar
authors.forename: G D
authors.initials: GD
authors.lastname: Lerman
authors.forename: J L
authors.initials: JL
authors.lastname: Blejer
authors.forename: M R
authors.initials: MR
authors.lastname: Nejamkis
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001116:Arenaviridae / Q000472:pathogenicity*; D006477:Arenaviruses, New World / Q000276:immunology / Q000472:pathogenicity*; D006478:Hemorrhagic Fever, American / Q000276:immunology / Q000382:microbiology; D007267:Injections; D007274:Injections, Intraperitoneal; D007964:Leukocytosis / Q000209:etiology; D051379:Mice; D051381:Rats; D011919:Rats, Inbred Strains; D013163:Splenomegaly / Q000209:etiology; D014613:Vaccines, Attenuated / Q000008:administration & dosage; D014765:Viral Vaccines / Q000008:administration & dosage
chemical_list: D014613:Vaccines, Attenuated; D014765:Viral Vaccines