Hello, I'm Luis Graca,
I'm a professor of Immunology at the University of Lisbon Medical School,
and I direct a research group at Instituto de Medicina Molecular in Lisbon.
Antibodies have been known for a long time.
Even before antibodies were known to be produced by B cells,
antibodies have been used therapeutically to treat, for example,
patients with tetanus as a way to neutralize the toxin leading to the disease,
and it was only in the '50s that it was shown that chickens that do not have a
bursa do not make B cells that were named
B cells exactly because of the relationship with this organ of chicken,
and as a consequence,
do not make antibodies.
T cells were also described shortly afterwards
as being produced in the thymus as early thymectomy of
mice was shown to compromise the ability of
these mice to make cellular responses and also humoral responses,
suggesting here a relationship between T and B cells for the production of antibodies.
Shortly afterwards, it was discovered that in fact,
T cells specialize in different functions and CD8 T cells
became known as cells that are important for the cytotoxic cellular responses,
while CD4 cells were important to help B cells leading to humoral immunity.
Even more recently, in the '80s,
it became known that the CD4 cells,
the ones that were considered to be helper cells, could also specialize.
At that time, it became known that some cells
can lead to type 1 responses being known as Th1,
and others to type 2 responses being known as Th2,
and the type one related T cells, the Th1 cells,
could drive B cells to make antibodies of specific classes,
while Th2 cells could drive B cells to make antibodies of different classes.
For example, IgE associated with allergic diseases has been ascribed
as a Th2-dependent type of antibody production.