GENERAL HISTOLOGY

Detailed explanation-1: -The first contact that an organism has with a particular antigen will result in the production of effector T and B cells which are activated cells that defend against the pathogen. The production of these effector cells as a result of the first-time exposure is called a primary immune response.

Detailed explanation-2: -The immune response occurring on the first exposure to an antigen is called primary response. The immune response occurring on second or subsequent exposures to an antigen with stronger response and in a shorter period of time is called secondary response.

Detailed explanation-3: -The primary immune response occurs after the first exposure to an antigen. A primary immune response results in the generation of memory immune cells. A secondary immune response occurs as a result of a second exposure to an antigen.

Detailed explanation-4: -IgM is the first antibody secreted by the adaptive immune system in response to a foreign antigen. Monomeric IgM is a heterotetramer of approximately 180 kDa.