Question

Name and explain by a short sentence the difference mechanisms of antigen uptake that occurs in immunological barrier.

Answer 1

Dendritic cells are considered to be professional antigen-presenting cells (APC). They reside in and patrol the skin and mucosal surfaces, thus playing an important role in the innate immune system with subsequent activation of T cell responses to provide a cell-mediated immunity against microbial pathogens.

Antigen uptake occurs through different mechanisms including phagocytosis, endocytosis, picnocystosis, and macropicnocytosis.

Dendritic cells have the ability to transport and carry the antigens from peripheral to primary lymphatic nodes where the antigen presentation takes place. These APC lead to the processing and presentation of antigens via major histocompatibility complex (MHC) class II molecules, thus bridging the innate and acquired immune response

This presentation results in interaction with and stimulation of helper T (Th) lymphocytes, which recognize peptide in association with either MHC class II or cytotoxic T (Tc) lymphocytes, which recognize peptide in association with MHC class I.

Stimulation of Th lymphocytes produces the growth and differentiation factors (cytokines) essential for the B lymphocytes that have responded to a more intact form of the antigen and that differentiate into antibody-producing cells.

Dendritic cells play a direct role with the stimulation of the B lymphocytes. It appears that DC can deliver antigen to the B lymphocytes in a more intact form than the processed form essential for stimulating T lymphocytes, and can release cytokines that assist the differentiation of the B lymphocytes into antibody-producing cells.