PRODUCTION OF ANTIBODIES AGAINST A PNEUMOCOCCAL ANTIGEN IN YOUNG MICE BY IMMUNIZATION WITH RECOMBINANT Lactococcus lactis

VILLENA JULIO; MEDINA MARCELA; RACEDO SILVIA; VINTIÑI ELISA; RAYA RAÚL; ALVAREZ SUSANA

Tafí del Valle-Tucumán-Argentina

Jornada; XXIII Jornadas Científicas de la Sociedad de Biología de Tucumán; 2006

Sociedad de Biología de Tucumán

We developed a strain of Lactococcus lactis that is able to express on its cell-wall the pneumococcal protective protein A (PppA) after the induction with nisin. The immunogenicity of orally administered L. lactis PppA, (108 cells/mouse) was evaluated in young mice (3 wk); with (L+) or without (L-) previous induction. Control mice (C) received PBS. Two immunization protocols were evaluated: a) for 5 d (L+1, L-1 and C1 groups); b) for 5 d followed with an equal boost two weeks later (L+2, L-2 and C2 groups). Serum, bronco-alveolar (B) and intestinal (I) specific antibodies (Ab) (IgA, IgG, IgG1 and IgG2a) and the number of IgA+ cells in lung and intestine were determined on d0 and d14 after treatments. L+1 and L+2 treatments induced production of Ab in serum, B and I while there were no detected in the other groups. The L+2 group showed higher levels of mucosal and serum Ab than L+1 mice. Intestinal and lung IgA+ cells increased significantly in L+1, L+2, L-1 and L-2 groups when compared with C1 and C2. There were no differences between L+1 and L-1, and L+2 and L-2; however L+2 showed higher numbers than L+1 group. Oral immunization with recombinant L. lactis PppA was able to induce production of specific antibodies against the PppA antigen in mucosal and systemic compartments.