Determination of IgA deficiencies in
saliva samples and the effect of time
on the IgA concentration using ELISA
Kalisvaart, L.
ID: i6215145
Tutorial group: 23
Faculty of Health, Medicine and Life Sciences
Maastricht University
Course BBS2001
30th October 2020
1
, 1. Introduction
In the human living environment, bacteria, viruses, fungi and parasites, acknowledged as
micro-organism, can cause several infectious diseases. The bodies resistance to prevent
these infectious diseases is defined as human immunity(1). The collection of cell and tissue
that mediate resistance to micro-organisms is described as the immune system. The
importance of an adequate immune system for health is drastically illustrated by people with
a defective immune system who are susceptible to life-threatening infectious diseases(1). In
addition, abnormalities in the immune responses are the causes of many inflammatory
diseases with serious morbidity and mortality(1).
The immune system consist of the innate immunity, which mediates the initial protection
against infections and the adaptive immunity which is stimulated by microbes that invade
tissues and adapts to the presence of microbial invaders(1). The adaptive immune system
consist of lymphocytes which express receptors that specifically recognize different
substances produced by microbes as well as non-infectious molecules called antigens(1). In
response to exposure to these antigens, antibodies are produced and secreted by B
lymphocytes of the adaptive immune system(1).
The antibodies secreted into the circulation and mucosal fluid function by eliminating
microbes and microbial toxins that are present in the blood, presented on the outside of host
cells and in the lumen of mucosal organs and thereby preventing infections (2). The
antibodies functioning in the lumen of mucosal organs are referred to as immunoglobin A
(IgA). IgA is the most abundant antibody isotype found in the human body and plays an
important role in the immune responses in the gastrointestinal tract (GI), the respiratory tract,
and the vaginal tract by interacting with mucosal epithelial cells, binding to receptors and by
high and low affinity antigen binding(2). The most predominant form of IgA is secretory IgA
(sIgA) and is mainly found in tears, saliva, sweat and secretion from the GI tract, vaginal and
respiratory tract. The immunoglobin is protected by secretory components of sIgA which
prevent degradation by proteolytic enzyme (2).
Through gene duplication two IgA isotypes, IgAl and IgA2, have arisen which differ in the
primary structure, function and location however how the different subclasses are balanced
or what balances them is not yet fully understood (3). The major difference in primary
structure between IgA1 and IgA2 can be found in the hinge region that lies between the two
Fab arms and the Fc region (3). IgA1 includes a very extended hinge due to the insertion of a
duplicated stretch of amino acids, which is lacking in IgA2. IgA1 is the most predominant
subclass found in serum as most lymphoid tissues have a predominance of IgA1-producing
cells(4). In a study on the concerted evolution of the immunoglobulin alpha-gene it was
2
saliva samples and the effect of time
on the IgA concentration using ELISA
Kalisvaart, L.
ID: i6215145
Tutorial group: 23
Faculty of Health, Medicine and Life Sciences
Maastricht University
Course BBS2001
30th October 2020
1
, 1. Introduction
In the human living environment, bacteria, viruses, fungi and parasites, acknowledged as
micro-organism, can cause several infectious diseases. The bodies resistance to prevent
these infectious diseases is defined as human immunity(1). The collection of cell and tissue
that mediate resistance to micro-organisms is described as the immune system. The
importance of an adequate immune system for health is drastically illustrated by people with
a defective immune system who are susceptible to life-threatening infectious diseases(1). In
addition, abnormalities in the immune responses are the causes of many inflammatory
diseases with serious morbidity and mortality(1).
The immune system consist of the innate immunity, which mediates the initial protection
against infections and the adaptive immunity which is stimulated by microbes that invade
tissues and adapts to the presence of microbial invaders(1). The adaptive immune system
consist of lymphocytes which express receptors that specifically recognize different
substances produced by microbes as well as non-infectious molecules called antigens(1). In
response to exposure to these antigens, antibodies are produced and secreted by B
lymphocytes of the adaptive immune system(1).
The antibodies secreted into the circulation and mucosal fluid function by eliminating
microbes and microbial toxins that are present in the blood, presented on the outside of host
cells and in the lumen of mucosal organs and thereby preventing infections (2). The
antibodies functioning in the lumen of mucosal organs are referred to as immunoglobin A
(IgA). IgA is the most abundant antibody isotype found in the human body and plays an
important role in the immune responses in the gastrointestinal tract (GI), the respiratory tract,
and the vaginal tract by interacting with mucosal epithelial cells, binding to receptors and by
high and low affinity antigen binding(2). The most predominant form of IgA is secretory IgA
(sIgA) and is mainly found in tears, saliva, sweat and secretion from the GI tract, vaginal and
respiratory tract. The immunoglobin is protected by secretory components of sIgA which
prevent degradation by proteolytic enzyme (2).
Through gene duplication two IgA isotypes, IgAl and IgA2, have arisen which differ in the
primary structure, function and location however how the different subclasses are balanced
or what balances them is not yet fully understood (3). The major difference in primary
structure between IgA1 and IgA2 can be found in the hinge region that lies between the two
Fab arms and the Fc region (3). IgA1 includes a very extended hinge due to the insertion of a
duplicated stretch of amino acids, which is lacking in IgA2. IgA1 is the most predominant
subclass found in serum as most lymphoid tissues have a predominance of IgA1-producing
cells(4). In a study on the concerted evolution of the immunoglobulin alpha-gene it was
2
