Which of the following statements are true of vaccines? (Read carefully and select all of the correct statements.)

A)Vaccines contain antigens to stimulate antibody production.
B)A vaccine antigen may be a pathogen that has been killed or attenuateD.
C)A vaccine antigen may be part of a pathogen or a toxoid.
D)The purpose of a vaccine is to take the place of a first exposure to a pathogen.
E)A vaccine stimulates the creation of memory cells (T or B or both) to a specific antigen.
F)On a second exposure to a pathogen, antibody production has a lag period, then IgG production follows IgA production.