Received: February, 2006.

Accepted: August 30, 2006.

Abstract published online: September 4, 2006.

Full paper published online: February 28, 2007.

IMMUNOPATHOLOGY OF RABIES INFECTION IN MICE SELECTED FOR HIGH OR LOW ACUTE INFLAMMATORY REACTION

ACHKAR S. M. (1), SINHORINI I. L. (2), RIBEIRO O. G. (3), CARRIERI M. L. (1), CERETTA R. S. (1), CONSALES C. A. (1)

(1) Pasteur Institute, São Paulo, Brazil; (2) Laboratory of Pathology, University of São Paulo, USP, São Paulo, Brazil; (3) Laboratory of Immunogenetics, Butantan Institute, São Paulo, Brazil.

ABSTRACT: Rabies is a severe and lethal disease that produces a slight inflammatory response during the infection process. We analyzed the immunopathological mechanisms that occur in the central nervous system (CNS) using mice genetically selected for maximal or minimal acute inflammatory reaction (AIRmax or AIRmin). As viral samples, we adopted the antigenic variant 3 (AgV3) of rabies virus from hematophagous bats and a fixed virus strain (PV1 43/3). Titration of specific antibodies was performed using enzyme-linked immunosorbent assay (ELISA). We observed a slight increase in IgG and IgG1 isotypes in infected AIRmax mice. Incubation period, determined by intracerebral inoculation with 100 LD50, was 6-7 days for PV1 43/4 strain and 9-10 days for AgV3. No difference in viral replication was noticed between AIRmax and AIRmin mice. Mortality was 100% with both viral strains. Histopathological analysis of brains and spinal cords showed inflammatory foci in all regions of the CNS. No differences were noticed in the number of neutrophils. Negri bodies were observed in practically all sites analyzed. Results suggested that inflammatory reaction is not a determining factor in the susceptibility to rabies infection.

KEY WORDS: rabies, virus replication, pathology, inflammation, immunoglobulin isotypes.

CONFLICTS OF INTEREST: There is no conflict.

CORRESPONDENCE TO:

SAMIRA M. ACHKAR, Instituto Pasteur de São Paulo, Avenida Paulista 393, Cerqueira César, São Paulo, SP, Brasil. Phone: + 55 11 3288 0088 ext. 116.

Email: samira_achkar@yahoo.com.br.