Lymphoid Organs and Circulation of Lymphocytes

What is the specialized integral membrane protein complex on cell surfaces that bind antigens recognized by lymphocytes?

Major Histocompatibility Complex (MHC)

Which type of protein plays a crucial role in the immune rejection of grafted tissue or organs?

MHC class I

What are the human cell counterparts of MHC class I and class II proteins often called?

Human Leukocyte Antigens (HLAs)

What do T lymphocytes recognize on MHC proteins?

Epitopes Signup and view all the answers

Where are MHC molecules synthesized before they leave the cell?

Rough Endoplasmic Reticulum (ER) Signup and view all the answers

What happens if the MHCs on cells of a tissue graft are not similar to those encountered by T lymphocytes during development?

Strong immune reaction is induced Signup and view all the answers

What do T lymphocytes consider unfamiliar MHC epitopes on graft cells as?

"Non-self" markers Signup and view all the answers

Which organelles are involved in the production of MHC class I proteins?

Golgi Apparatus and Rough ER Signup and view all the answers

What process do MHC class I proteins undergo before leaving the ER?

Sites with various proteasome-derived peptide fragments bind to MHC class I proteins. Signup and view all the answers

What is the function of T lymphocytes towards cells with unfamiliar MHC epitopes on tissue grafts?

Eliminate them as potentially tumorigenic, infected, or abnormal cells. Signup and view all the answers

Which cells display MHC class I molecules presenting self-antigens?

All nucleated cells Signup and view all the answers

Where are MHC class II proteins synthesized and transported to the cell surface?

Mononuclear phagocyte system Signup and view all the answers

What is the role of MHC class II proteins in antigen presentation?

Signal T lymphocytes against pathogenic cells Signup and view all the answers

What type of rejection occurs in homografts (allografts)?

Immunological rejection Signup and view all the answers

Which type of graft involves identical twins?

Isografts Signup and view all the answers

Which cells are considered 'professional' antigen-presenting cells (APCs)?

Dendritic cells Signup and view all the answers

What induces the transient expression of MHC class II on certain local cells during inflammation?

Interferon-γ Signup and view all the answers

Where do progenitors of B lymphocytes mature and differentiate further?

Bone marrow Signup and view all the answers

What is the main function of stem cells in adults for all lymphocytes?

Red bone marrow Signup and view all the answers

What is the primary function of helper T cells?

Activate B cells into plasma cells Signup and view all the answers

Which surface proteins are involved in activating different responses to antigens for B and T cells?

CD4 and CD8 Signup and view all the answers

How do cytotoxic T cells recognize antigens on foreign or virus-infected cells?

Via interaction with MHC class I molecules Signup and view all the answers

What is the primary role of fibroblastic reticular cells in lymphoid tissue?

Produce reticulin fibers Signup and view all the answers

Which type of lymphocytes bind antigens directly?

B cells Signup and view all the answers

What is the function of cytotoxic T lymphocytes (CTLs) when activated?

Kill foreign or virus-infected cells Signup and view all the answers

Which lymphocytes are characterized by the presence of CD8?

Cytotoxic T cells Signup and view all the answers

What is the main function of fibrous reticulin fibers in lymphoid tissue?

Support lymphocytes Signup and view all the answers

How do T lymphocytes recognize antigenic epitopes?

Via surface protein complexes T-cell receptors (TCRs) Signup and view all the answers

What is the primary role of naive lymphocytes in newborn infants?

Recognize antigens Signup and view all the answers

Which cells release perforins and granzymes to trigger apoptosis?

Cytotoxic T cells Signup and view all the answers

What is the function of Regulatory T cells (Tregs)?

Inhibiting specific immune responses Signup and view all the answers

Which type of T lymphocytes contain γ (gamma) and δ (delta) chains in their TCRs?

γδ T lymphocytes Signup and view all the answers

Where do γδ T cells primarily migrate to in the body?

Epidermis and mucosal epithelia Signup and view all the answers

What happens to B cells when BCRs bind an antigen?

Endocytosis of the antigen Signup and view all the answers

What stimulates several cycles of cell proliferation in B lymphocytes?

Cytokines from helper T cells Signup and view all the answers

What type of cells have long filamentous processes and interact with B lymphocytes in secondary lymphoid tissues?

Follicular dendritic cells (FDCs) Signup and view all the answers

What characterizes secondary nodules in secondary lymphoid tissues?

Presence of large lymphoblasts in germinal center Signup and view all the answers

What is the primary function of plasma cells derived from activated B cells?

Secrete antibodies that bind specific epitopes Signup and view all the answers

How are memory B cells different from plasma cells?

Memory B cells are long-lived and responsible for rapid antibody production upon reinfection. Signup and view all the answers