Lymphocytes Flashcards
There is immune ___ and immune ____.
Protection
Pathology
Most pathogens enter the body through ___ ____ of the digestive, respiratory, and reproductive tract. It is a thin and ____ layer epithelium. ___ ____ are encapsulated lymph nodes in the gut that drain the gut lymph.
Mucosal surfaces
Permeable
Peyer’s patches
Lymphocytes are ___ and ___. They are part of the ____ immune system.
T cells
B cells
Adaptive
B cells have receptors on their surface called ____ (Ig) and recognizes pathogens
Antibodies
CD4+ helper T cell have receptors on their surface that recognize ____ presented by MHC class II from an antigen presenting cell or infected cell. They produce factors that help ___ cells and ___ __ cells.
Peptide
B
CD8+ T
CD8+ cytotoxic T cell ___ infected cells. They have receptors on their surface that recognize ____ presented by MHC class I.
Kill
Peptide
B lymphocytes mature in the ___ ___. They reside in ___ ___, ____, and blood. Each B cell expresses a unique __ ___ receptor (BCR) which is the ____ receptor.
Bone marrow
Lymph nodes
Spleen
B cell
Antigen
During infection, only B cells with the antigen-specific BCR clonally expand and secrete _____, which is critical for protection. After clearance, some B cells are long lived and have ___.
Antibody
Memory
An ____ is a secreted BCR by an activated B cell. Two identical ___ chains and two identical ___ chains. The ends of the chains combine to form a ___ ___. This region (fab fragment) is the antibody ____ site. The ___ region is constant with no variation and binds FcR on innate cells.
Antibody
Heavy (H)
Light (L)
Variable (V) region
Binding
Fc
An ____ is anything that stimulates an adaptive immune response and binds BCR
antigen
___ ___: lymphocytes that express a self-reactive antigen receptor (BCR or TCR) are deleted during development
Central tolerance
VDJ recombination occurs in immature B and T cells to generate a unique ___ or ___. Each cell ____ expresses a unique receptor allowing for limitless recognition. This is unique is each person.
BCR
TCR
randomly
Central tolerance ____ most potentially harmful lymphocytes but is imperfect causing _____.
Deletes
Autoimmunity
B cells mature in the bone marrow. ___ ___ occurs in the bone marrow where immature B cells bound to self are removed. ____ of mature B cells to the lymphoid organs and become activated by foreign antigens.
Negative selection
Migration
Activated B cells give rise to ___ cells and ____ cells.
Plasma
Memory
_____ diseases can be due to the failure to delete all self-reactive lymphocytes
Autoimmune
Diagram of B cell development:
____ B cell is mature and circulates in the blood and secondary lymphoid organs (____ ____ and ____) and have never encounter antigen. They are not activated.
Naive
Lymph nodes
Spleen
Clonal selection theory:
1. Each lymphocyte bears a unique ___ or ___
2. Interaction between ___ and receptor is specific and required for lymphocyte activation and differentiation
3. All daughter cells from a single lymphocyte express the same ___ ___.
4. After clearance, most lymphocytes die but a few persist and form ____ that lasts for years
BCR or TCR
antigen
Antigen receptor
Memory
A small number of genes can become millions of different receptors through ____ ____. Random joining of gene segments ____ (heavy) or ___ (light) creates a unique variable region. Heavy and light chains combine with a ____ region.
VDJ recombination
V-D-J
VJ
Constant
Antibody isotypes:
IgM, IgG, IgA, IgE, IgD
Ig class is determined by change in ___ ___ (isotope switching) in B cells during immune response
Constant region
____ is the first antibody secreted after primary infection. It activates classical complement pathway. Weak opsonin meaning receptors can’t bind Fc
IgM
____ is the most abundant in serum after secondary response. Most abundant in plasma. Crosses placenta. Two antigen binding sites .
IgG
