IMMUNOLOGY

Detailed explanation-1: -When first exposed to antigen “A", we begin to make low levels of antibody in about a week However, a second exposure to antigen “A” produces a much faster response, and several orders of magnitude higher levels of antibody. The ability of antibody to bind antigen also increases dramatically in the secondary response.

Detailed explanation-2: -IgM is the primary antibody produced during an initial antigen challenge. Yet, upon subsequent antigen exposure, follicular B cells undergo isotype switching, resulting in IgG, IgG, IgE, or IgA production.

Detailed explanation-3: -(noun) The act of exposure to the same pathogen after the initial immune response. Memory B and T cells work to rapidly eliminate the pathogen to prevent reinfection.

Detailed explanation-4: -In the primary response to infection, antibodies are secreted first from plasma cells. Upon re-exposure to the same pathogen, memory cells differentiate into antibody-secreting plasma cells that output a greater amount of antibody for a longer period of time.

Detailed explanation-5: -The secondary antibody response is characterized in its first few days by the production of small amounts of IgM antibody and larger amounts of IgG antibody, with some IgA and IgE.

Detailed explanation-6: -In the present study, IgG was absorbed before detection of IgM and IgA in two different IFA assays. Accordingly, the sensitivity of the IgM and IgA assays after IgG absorption, rather than the biology of the host response, might contribute to this phenomenon.