Please fill in all the blanks. Inducement of T-Dependent Antibody Immunity with Clonal Selection Activation of T-dependent antibody immunity requires the assistance of type 2 helper T (Th2) cells. 1. In antibody immunity, an APC's MHC II protein-epitope complex activates a helper T cell (Th cell) bearing a complementary 2. APCs present epitopes on MHC molecules and form an immunological synapse with Th using the complementary TCR. 3. CD 4 MHC interaction stabilizes the synapse, and the delivers a second signal. 4. (IL-4) then induces the Th cell to become a type T cell (Th2). 5. The Th_cell interacts with cells displaying epitope on MHC II and releases . Since only B cells displaying the epitope the Th2 cell recognizes are activated, this process is called selection. 6. The activated B cell proliferates rapidly and the clones differentiate into either B cells or cells. 7. with cells live for only a short time but secrete large amounts of antibodies, beginning 8. and class switching as they get older. antigen. B cells migrate to lymphoid tissues to await a subsequent encounter with the same Types of Acquired Immunity Specific immunity is characterized either naturally or artificially acquired and as either active or passive. 1. When the body mounts a specific immune response against an infectious agent, the result is called immunity. 2. The passing of maternal IgG to the fetus and the transmission of secretory IgA in breastmilk to a baby are examples of immunity. 3. immunity is achieved by deliberately injecting someone with antigens in vaccines to provoke an active response, as in the process of immunization. 4. immunotherapy involves the administration of preformed antibodies in antitoxins or antisera to a patient. Immune Responses 1. The first adaptive response to a particular antigen is called the . As a result of this initial encounter, the adaptive immune system "remembers" the mechanism that was effective against that specific antigen. 2. If the same antigen is encountered later in life, a stronger antigen-specific adaptive immune response occurs, called the response. .