Running head: B CELLS AND T CELLS 1
B Cells and T Cells
Kimberly Goodwin
B CELLS AND T CELLS 2
B Cells and T Cells
Lymphocytes found in the immune system come from the same area as hematopoietic
stem cells, although they mature in various lymphoid primary organs. Looking at it T
lymphocytes mature in the thymus where B lymphocytes mature in a person’s bone marrow. The
differentiation process is very similar between B cells and T cells because the recombination of
immunoglobulin genes in each stage is capable of determining the development and protein
expression of each cell. T cells and B cells are capable of interacting with each other as well as
other cells found in the body; they do this to be capable of functioning as a portion of the
immune system response. Cytokines are the proteins that are found to be responsible for the
communication between the immune system cells and other cells in the body; this contributes to
the humoral as well as the adaptive responses.
B lymphocytes are known to originate from stem cells which are able to develop into
mature antibody forming cells, this occurs during development that goes through various
different stages of the differentiation process. Ig also known as immunoglobulin, gene
reorganizations outline various stages of the differentiation pathways, this is also known to
represent checkpoints in the development. In the bone marrow B cells have their primary source
for the differentiation process, this is way bone marrow in mammals is known to be a primary
lymphoid organ.
The creation of Pre-B cells as well as Pro-B cells is the early stages found in B cell
differentiation. Hematopoietic stem cells are able to obtain signals from the action of cytokines,
this is one thing that instills survival, and improves proliferation of the cells found in the early
stages of a B cells lineage. The beginning rearrangement of immunoglobulin genes happens at
the heavy chain locus; this is where a D gene segment is capable of being rearranged into a J ҥ ҥ
gene segment. This helps to form the DJ unit. This allows for the B-cells to be capable of
B CELLS AND T CELLS 3
expressing the CD19 in each specific stage of various developments which can include the
mature B cell. The CD19 expression is not able to happen in the plasma cell (Coico & Sunshine,
2009).
Another rearrangement of the immunoglobulin genes, this provokes the next stage setup
in the B cell differentiation; this stage is when the VH gene is able to join the D J segment thatҥ ҥ
was rearranged earlier. This specific rearrangement creates the VDJ unit, which allows the Pre-B
cell to be capable of synthesizing a µ chain; this creates the beginning of the expression of
CD10. It is very important to know that when the V-DJ arrangement does not become
productive on the first of the two parent chromosomes, then the rearrangement must take place
on the second chromosome. The second chromosome is capable of making the µ chain, only
