Cross-reaction between proteins of Larrea divaricata Cav. (jarilla) and several antigens of Pseudomona aeruginosa

SASSO, CORINA V; MATTAR, MARÍA A ; DAVICINO, ROBERTO C ; MATINO, RENZO F; CASALI, YOLANDA A; B. MICALIZZI

Buenos Aires

Congreso; LVIII Reunión Sociedad Argentina de Inmunología; 2010

Sociedad Argentina de Inmunología

Larrea divaricata Cav. (jarilla) is a plant found in Argentine and used to treat different pathologies. Little is known about its immunological properties. Pseudomonas aeruginosa is a Gram negative bacillus that is considered a nosocomial pathogen. The aim of our work was to study the cross-reactivity between P. aeruginosa’s proteins and those from an extract aqueous of jarilla (JPCE). JPCE was partially purified by ultrafiltration. The strain of P. aeruginosa ATCC 27853 was used. Cellular proteins by sonication, total membrane, citoplasmic and extracellular antigens were obtained. Proteins were analized by SDS-PAGE. To evaluate the cross reactivity of anti-JPCE sera an ELISA and Western Blot (WB) tests were used. To confirm the presence of common antigens an ELISA inhibition test was carried out. The similarity between protein profiles on SDS-PAGE and WB was expressed as the Dice correlation coefficient (SD). A high number of bands in the JPCE (18 bands) was identified by SDSPAGE. The proteic profiles of P. aeruginosa showed 12-18 bands. The bacterial bands showed a SD greater than 36% in relation to JPCE profile. Several common immunoreactive bands were detected by WB (SD=35% to 85%). No significant differences in IgG titers of anti-JPCE serum against sonicated, membrane and extracellular proteins (>1/900) were found. Significant difference (p<0,006) was observed in heterologous reaction with citoplasmic proteins. The cross reaction observed between JPCE and P. aeruginosa suggest that anti-JPCE recognizes epitopes on bacterial proteins. The binding of antibodies to immobilized JPCE (on the ELISA plaque) was inhibited (15%-40%) by preincubation of the antibodies with the four bacterial antigens. In conclusion, our data demonstrate clearly that bacterial antigenic epitopes were consistently detected by antibodies elicited with L. divaricata proteins. These findings could be relevant in the development of vaccines against infections caused by P. aeruginosa.