Immunomodulatory effects in combined vaccines for children

LAVIGNE MV; CASTRO MS; ANDINO PJ; MANGHI MA

Córdoba, Argentina

Congreso; VII Congreso Latinoamericano de Inmunología; 2005

Asociación Latinoamericana de Inmunología

Considering the great deal of knowledge about the host-pathogen interactions that has been achieved over the last years, an insightful study of modulatory effects that antigen combinations have on the immune response they elicit is a high priority. We studied the immune response of BALB/c mice immunized with vaccines composed by different combinations of the following antigens: diphtheria toxoid (D), tetanus toxoid (T), Salmonella typhi (St) and whole-cell Bordetella pertussis or its soluble antigens (Pw and Pa, respectively). The proliferative response of spleen cells cultured in the presence of specific antigens, the presence of cytokines on cell-culture supernatants and serum antibody levels were assessed. If mice are immunized with a combined vaccine that contains Pw, memory T lymphocytes able to proliferate to in vitro stimulation with Bordetella pertussis are produced, but these cells cannot be found if Pw is replaced by Pa (soluble antigens). While DTPw or DTPaSt immunizations induce a mixed Th1/Th2 tetanus response, DTPa immunization induces a Th2 tetanus immune response. A similar modulatory effect is showed through diphtheria, tetanus and pertussis antibodies. Taking into account that tetanus immune response is evoked several times during the lifetime, avoiding Th1 tetanus immune responses should be of interest because this inflammatory response is unnecessary and yet could be harmful in autoimmune-prone individuals. According to this assessment we provided evidence that priming with DT and Pw with an interval of 14 days, followed by DTPa boosters appropriate immune responses against DTP vaccine antigens can be generated.