Search for agglutinating antibodies to Leptospira and Leptonema in horses, São Paulo, Brazil

Soros de 922 eqüinos aparentemente sadios, mantidos na Fazenda do Instituto Butantan (São Roque, SP) para produção de soros hiperimunes, foram analisados quanto à presença de anticorpos para sorovares de Leptospira interrogans e para Leptonema illini, através da reação de aglutinação microscópica (MA). Entre os 807 (87,5%) animais positivos, 659 (81,7%) reagiram com mais de um sorovar, com títulos entre 1:100 e 1:6.400, havendo predomínio de títulos baixos (≤ 1:400); 84% dos soros positivos reagiram com representantes do sorogrupo Icterohaemorrhagiae e 79,2% com Leptonema illini. Dos 23 sorovares utilizados, apenas o tarassovi não reagiu.Sera from 922 apparently health equines intended for therapeutic sera production in a farm of the Instituto Butantã in São Roque, State of São Paulo. Brazil, were examined for detection of antibodies to serovars of Leptospira interrogans and to Leptonema illini by the microscopic agglutination (MA) test. Significant antibody titres were found in 807 sera (87.5%) and 659 (81.7%) of those sera reacted to more than one serovar at titres ranging from 1: 100 to 1:6,400 with predominance of low titres (≤ 1:400). From the 23 screening serovars, only tarassovi did not react. The most common reactions among positive sera occurred to antigens from the Icterohaemorrhagiae serogroup (84%) and to Leptonema illini (79.2%)

Peripheral Blood Mononuclear Cell Activation Induced by Leptospira interrogans Glycolipoprotein

Leptospira interrogans glycolipoprotein (GLP) has been implicated in pathological and functional derangement seen in leptospirosis. The goal of this study was to evaluate GLP's ability to induce cellular activation, as assessed by cytokine production and expression of surface activation markers. GLP extracted from either pathogenic L. interrogans serovar Copenhageni or nonpathogenic Leptospira biflexa serovar Patoc (GLPp) was used to stimulate peripheral blood mononuclear cell cultures from healthy donors. Supernatant cytokine levels were measured by enzyme-linked immunosorbent assay. Expression of CD69 and HLA-DR on lymphocytes and monocytes, as well as lipopolysaccharide (LPS) binding, were measured by flow cytometry. At 6 h of incubation, GLP induced a significant rise in tumor necrosis factor alpha levels, which dropped progressively until 72 h of incubation. Interleukin-10 peak levels were obtained at between 24 and 48 h, with sustained levels until 72 h of incubation. The response magnitude was proportional to the GLP dose. CD69 expression on T lymphocytes and monocytes increased significantly, as did HLA-DR expression on monocytes. GLPp induced no CD69 or HLA-DR expression. GLP did not block biotinylated LPS binding to monocytes, suggesting that different pathways are used to induce cell activation. In conclusion, GLP induces cellular activation and may play a major role in the pathogenesis of leptospirosis