Antigen-presenting cells make contact with T-cells via cellular junctions. Which of the following is likely to mediate this junction if liquid can pass between the cells in the extra-cellular matrix but can not pass from cell to cell?         a.   Cadherin       b.   Connexin       c.   COPII       d.   Claudin

Each of the following statements is false. Please correct. a. Mature T cells are found only in the lymph nodes and spleen b. The pluripotent stem cell is one of the most abundant cell types in the bone marrow c. There are no stem cells in blood d. Activation of macrophages increases their expression of MHC class I molecules, allowing them to present antigen to CD4+ TH cells more effectively e. B cells develop in the thymus f. Lymphoid follicles are present only in the spleen and lymph nodes g. The FRC guides B cells to follicles h. Infection has no influence on the rate of hematopoiesis i. Follicular dendritic cells can process and present antigen to T lymphocytes j. Dendritic cells arise only from the myeloid lineage k. All lymphoid cells have antigen-specific receptors on their membrane l. All vertebrates generate B lymphocytes in bone marrow m. Only mammals have a thymus n. Jawless vertebrates do not have lymphocytes

Give ONE example of how a defect in a T Reg cell could lead to an immunological disorder or disease.

Explain why each choice (a-d) is correct or incorrect.  In order for an antigen to activate or sensitize a T helper cell, the antigen must be a. coated with antibodies b. displayed on the surface of an APC along with MHC antigens c. displayed on the surface of another T cell with IgD antibodies d. partly digested by a natural killer cell

Which of following is not a type of T lymphocyte? a. Helper T cell b. Memory T cell c. Cytotoxic T cell d. Mast T cell