Adaptive Immune Responses Flashcards
Primary Lymphoid Organs
The organs that initially develop lymphocytes. The bone marrow and thymus.
Secondary lymphoid Organs
Lymph nodes, spleen, tonsils, and lymphocyte accumulations in the linings of the intestinal,respiratory,genital and urinary tracts.
T-Cell Classification
CD4/CD8 T-cells. Rarely have receptors for both. Cytotoxic T Cells are cells that have been activated to destroy the body’s own cells (cancer, cells infected with virus, etc).
T-Helper Cells
They combine with antigen, then undergo activation. Once activated they migrate to the site of B-Cell activation. B cells bind with antigen, but alsorequire direct contact with T-helper cells via cytokine secretion.
Th cells ALSO activate cytotoxic T-cells. Th cells secrete cytokines and influence other cells to activate cytotoxic T-cells.
T-Cell Receptors
The T-cell receptor cannot combine with antigen unless the antigen is first complexed with certain of the body’s own plasma membrane proteins.
Class I MHC Proteins
Found on the surface of virtually all cells EXCEPT erythrocytes. Complex with antigens and present to T-Cells. Cytotoxic T-cells require I MHC proteins.
Class II MHC Proteins
Found mainly on the surface of macrophages, B-lCells, and dendritic cells. T-Helper Cells require II MHC proteins.
MHC I Complexes
Complex with Cytotoxic T-cells, express antigens from self-cells.
NK Cells
NK cells are NOT antigen-specific. The mechanism of recognition of ‘sick’ cells is unknown. Their participation in the immune response is greatly enhanced either by certain antibodies or by cytokines secreted by helper T cells.
Clonal Deletion
T-Cells with receptors capable of binding self proteins are destroyed by apoptosis.
Clonal Inactivation
This occurs in the periphery and causes self-reacting T-Cells to become inert.
