Lecture 13 Flashcards
What are the main components involved in the adaptive immune response?
The adaptive immune response involves lymphocytes, specifically B cells and T cells.
Define adaptive immunity.
Adaptive immunity refers to the resistance to pathogens that develops as a result of the B and T cell memory generated from an immune response against a specific pathogen.
What are the main effector cells for B-cells, and what is their primary function?
The main effector cells for B-cells are called plasma cells. Upon encountering antigens, B-cells differentiate into plasma cells. Plasma cells are specialized to produce and secrete large quantities of antibodies, also known as immunoglobulins.
These antibodies are essential for the humoral immune response, as they bind to specific antigens and mark them for destruction or neutralization by other components of the immune system.
What are the main effector cells for T-cells, and what is their primary function?
The main effector cells for T-cells are cytotoxic T-lymphocytes (CTLs). CTLs play a crucial role in cell-mediated immunity.
They recognize specific antigens presented on the surface of virus-infected cells or cancerous cells through their T-cell receptors (TCRs).
Once activated, CTLs induce apoptosis (cell death) in these target cells, effectively eliminating them from the body. This mechanism is vital for controlling viral infections and preventing the spread of cancer.
What are dendritic cells (DCs) and macrophages, and what is their role in the adaptive immune response?
Dendritic cells (DCs) and macrophages are both antigen-presenting cells (APCs). They capture antigens by engulfing foreign material and subsequently present these antigens to T and B cells.
After encountering antigens, DCs and macrophages become activated and migrate to the draining lymphatic vessels. From there, they travel to the lymph nodes, where they interact with T and B cells to initiate the adaptive immune response.
This process leads to the activation and proliferation of specific T and B cells, which then differentiate into effector cells to combat the invading pathogens (travel to the location of infection)
Describe the difference between the epitopes recognized by T-cell receptors vs antibodies.
Antibodies can bind to dis-contiguous AND contiguous epitopes, but HAS to be on the surface of the antigens. Same with B-cell receptor
T-cells ONLY recognize contiguous (linear) and it does NOT have to be on the surface of the antigens
Can one protein have more than one epitope?
Yes, one antigen presenting cell can present multiple epitopes
What are T helper cells (CD4+), and what role do they play in the immune response?
T helper cells (CD4+) provide crucial assistance to the immune response by producing cytokines upon activation.
These cytokines serve to regulate and coordinate the activities of other immune cells.
Upon recognizing specific epitopes, T helper cells can initiate cytokine production, which activates the JAK-STAT signaling pathway, leading to a transcriptional response in target cells.
What are cytotoxic T cells (CD8+), and what is their primary function?
Cytotoxic T cells (CD8+) are key effector cells in cell-mediated immunity, especially in combating viral infections (anti-viral immune cells).
Their principal function is to recognize and eliminate infected cells. Upon encountering virus-infected cells, cytotoxic T cells induce apoptosis, effectively removing the viral threat from the body.
What is MHC I, and where is it expressed?
MHC I (Major Histocompatibility Complex Class I) molecules are proteins found on the surface of almost all nucleated cells in the body, including cells like those in the immune system (hematopoietic cells).
What type of peptides do MHC I molecules bind, and how are they presented?
MHC I molecules bind peptides that are derived from proteins synthesized within the cell (endogenous proteins).
These peptides are recognized by CD8+ T-cells, which play a crucial role in immune responses.
What is the role of CD8+ T-cells in response to MHC I presentation?
CD8+ T-cells, also known as cytotoxic T-cells, recognize the peptides presented by MHC I molecules. If these peptides come from infected or abnormal cells, CD8+ T-cells destroy these cells, contributing to the elimination of viruses or other intracellular pathogens.
What is MHC II, and where is its expression restricted?
MHC II (Major Histocompatibility Complex Class II) molecules are found only on certain immune cells known as antigen-presenting cells, including B-cells, macrophages, and dendritic cells.
What type of peptides do MHC II molecules bind, and how are they acquired?
MHC II molecules bind peptides that come from proteins that were taken up from outside the cell (exogenous proteins). Antigen-presenting cells process these proteins into peptides and present them via MHC II to CD4+ T cells.
How are MHC II-presented peptides recognized, and what cells are involved?
MHC II-presented peptides are recognized by CD4+ T cells. When an antigen-presenting cell encounters a pathogen, it engulfs the pathogen and breaks it down into peptides, which are then presented by MHC II. CD4+ T cells, upon recognizing these peptides, activate immune responses against the pathogen.
