Lecture 5 9/6/23 Flashcards
What are the two types of MHC?
-MHC class 1
-MHC class 2
Which cells have MHC class 1?
nearly all host cells
Which cells have MHC class 2?
antigen-presenting cells
What type of pathogens are presented using MHC class 1?
-intracellular pathogens
-viruses
How do host cells prevent the immune system from targeting them?
-proteasome will break down excess normal proteins from the cell
-cell will present their normal proteins on MHC class 1 for immune cells to recognize
What type of immune cell is stimulated when host cells present foreign antigens on MHC class 1?
cytotoxic T cells
What type of pathogen is presented using MHC class 2?
extracellular pathogens
How do APCs use MHC class 2 to present foreign antigens?
-APCs phagocytose and digest extracellular pathogens
-the foreign antigens are expressed on MHC class 2
Which immune cell types are activated by foreign antigens on MHC class 2?
-helper T cells
-B cells
What are the potential roles of the lymphoid organs?
-regulate lymphocyte production
-provide environment for trapping and processing foreign antigens
-maximize opportunity for lymphocytes to encounter foreign antigens
What are primary lymphoid organs?
where lymphocytes are produced and educated
What are secondary lymphoid organs?
where lymphocytes recognize and respond to antigens
Which lymphoid organs are considered primary?
-thymus
-bursa
-peyer’s patches
-bone marrow
Which lymphoid organs are considered secondary?
-tonsils
-spleen
-lymph nodes
-peyer’s patches
-bone marrow
Why is it important that lymphocytes are trained to avoid self-reactivity?
don’t want immune cells reacting to host cells/antigens the same way they do foreign antigens
Which lymphoid organ produces T cells?
thymus
Which lymphoid organs produce B cells, and in which animals?
-bursa of Fabricius (birds)
-bone marrow (primates/rodents)
-intestinal lymphoid tissues (ruminants)
What are the characteristics of the lymph nodes?
-filter lymphatic fluid
-site of antigen-lymphocyte interaction
Where are B cells found within the lymph node?
cortex
Where are T cells found within the lymph node?
paracortex
Which cell types are found in the medulla of the lymph node?
APCs (dendritic cells and macrophages)
What is unique about pig lymph nodes?
structurally inverted, with medulla outside and cortex inside
What is the role of the spleen?
filters antigen from blood
What is the function of the red pulp?
red cell storage and hematopoiesis
What is the function of the white pulp?
lymphoid tissue
What do T cells form in the spleen?
periarteriolar lymphoid sheaths
What do B cells form in the spleen?
follicles containing germinal centers
Where are APCs found in the spleen?
in the marginal zone surrounding white pulp
