T cell help mechanisms in the <em>in vitro</em> antibody response: the role of linked and non-linked recognition interactions.

Mechanisms by which T and B lymphocytes co-operate in the in vitro secondary antibody response to trinitrophenyl-conjugated soluble protein antigens were investigated. The generation of antibody responses was analyzed when haptenic and carrier determinants were either linked or non-linked. Ability to co-operate through each of these mechanisms was influenced by the experimental conditions employed, particularly the mode of preparation of the T cells and the antigen concentration used. Nylon wool filtration of T cells may deplete a T helper population involved in non-linked recognition interactions.