M2e-specific antibody responses induced by M2e-MAP vaccine. Mice were vaccinated with M2e-MAP plus FCA/FIA (s.c.) or alum (i.m.) adjuvant for a total of 3 times. Mice receiving FCA/FIA or alum alone were served as adjuvant controls. Mouse sera were collected pre-immunization and 10 days post-each immunization for detection of M2e-specific antibodies by ELISA. The end-point titer of each sample was determined as the highest dilution that yielded an OD450 nm value greater than twice that of similarly diluted serum sample collected pre-vaccination. The data are expressed as geometric mean titer (GMT) ± standard deviation (SD) of 10 mice per group. The lower limit detection (1:10) is indicated by a dotted line. Experiments were repeated three times.