The aging is associated with a decline in immune response, manifested by an increment of infections disease, cancer and autoimmunuty. We have previously studied the auto and heteroimmune response in mice of different ages immunized with antigens of Trypanosoma crusi (S-105) and observed that 20 days and 12-month-old BALB/c mice showed decreased response to foreign antigens and increased response to autoantigens when compared with 3.month-old immunized mice. The immune response against the foreign antigen was correlated with the presence of cellular infiltrate in both skeletal and heart muscle. In the present study we analyzed the involvement of the lymphatic node cells (LNC) in the S-105 immune response.
BALB/c mice, aged 20 days, 3 and 12 months were immunized i.d. with 6 mg of S-105 on day 0 and with 1 mg on days 15 and 21, plus Bordetella pertussis (Bp) as adjuvant. The control animals received Bp only. On day 10 post third immunization, lymph nodes from the all groups of mice were removed and the LNC were transferred to normal syngenic, 3 month-old mice (n:6 per group). The DTH response against S-105 studied on day 1 post transfer was positive only in the recipients of LNC from 3 month-old immunized mice (p<0,05). The recipients mice were immunized on day 7 post transfer with 6 mg of S-105 plus Bp and the humoral response analyzed by ELISA on days 7 and 15 post transfer. On day 7 no antibodies against S-105 were detected in the recipients of the LNC from 20 days (p<0,05) and 3 month-old immune mice (p<0,01). In other experiment 3 month-old mice (n:5) received LNC mixed from 3 month-old and 12-month-old mice. Cellular and humoral response were not detected in these recipients. When non adherent LNC to and adherent LNC to PVC from 3 and 12-month-old mice were transferred to 3 month-old mice (n:5 per group), we observed that only the recipients of non adherent LNC (from 3 month-old mice presented immune response against S-105 (p<0,05).
In our experimental model we observed that the two poblations adherent and non adherent LNC of aged animals do not transfer a response against the foreign antigen and that when these cells are mixed with LNC from 3 month-old mice, the inhibits the transfer of response against S-105.
