The route and number of immunizations influence the generation of BTAA reactive antibodies. (A) Effect of various routes of immunization on anti-BTAA antibody generation. Balb/c mice were immunized weekly for four weeks with PBS, BTAA alone (25 µg), or BTAA (25 µg) in combination with NLP (1 unit) by s.c., i.p. and i.v. routes. Seven days after the last immunization the mice were bled and anti-BTAA antibodies in the sera were measured by ELISA. Each data point represents the mean ± 1 SD of six observations. *Significantly higher than other values (P < 0.01). (B) Effect of multiple immunizations on anti-BTAA antibody generation. Groups of mice were immunized i.v. weekly for 1 to 4 weeks. Generation of anti-BTAA antibody was measured by ELISA after one week of immunization. Data from a representative mouse is presented for each group. *Values for the group immunized with BTAA and NLP are significantly higher than those of the other groups (P < 0.001).