Immunoglobulin G Plays Significant Health Role In The Human Body

November 12, 2012

Immunoglobulin G Plays Significant Health Role In The Human Body

Immunoglobulin G is one of several immunoglobulins that have a significant role within the human body, found in secretions, plasma and on the B-cell membrane.

All immunodeficiency diseases are grouped into conditions that affect at least, if not more than, one of the four key immune system limbs, which are:

  1. Complement

  2. B cells (humoral immunity)

  3. T cells (cell-mediated immunity)

  4. Phagocytes

Immunoglobulin G, A, D, M and E

Immunoglobulins intermediate the b-cell immunity, which is also known as the humoral immunity. This immunity is different from the T-cell immunity, as the T-cell immunity is regarded as the cellular immunity. It’s also different from the phagocytic immune function. Immunoglobulins are actually protein molecules that have antibody activity and are generated by plasma cells (or lethal cells of B-cell differentiation).

Immunogloblins have significant roles within the humoral immunity, consisting of five main isotypes like:

  • Immunoglobulin G

  • Immunoglobulin A

  • Immunoglobulin D

  • Immunoglobulin M

  • Immunoglobulin E

Immunoglobulin G is the most abundant of all five isotypes (73 percent). It’s got a molecular weight of about 150kd. Immunoglobulin G is found in external secretions and plasma and articulated on the B-cell membrane. Now, the immunoglobulin G isotype is divided into four additional classes such as:

  • IgG1

  • IgG2

  • IgG3

  • IgG4

Thankfully, for easy recall, serum concentrations of these classes (IgG1, IgG2, IgG3 and IgG4) openly associate with their numerical language. Thus, IgG1 has more serum concentration than the other three.

In the early 1950s, Ogden Bruton talked about classic X-linked agammaglobulinema, which is the result of a B-cell deficiency and occurred in an eight-year-old child. The child has numerous recurring pyogenic infections with recurring sepsis episodes with the exact serotypes of pneumococcus and numerous mumps episodes. However, he did not have any antibodies against them. Serum protein electrophoresis was just introduced to the market, which showed that the child’s blood was missing the g fraction.

Consequently, patients were labeled with detectable B-cells and lymphoid tissue but reduced levels of IgG and/or had no certain antibodies. Those conditions fit into the following categories:

  • Common variable immunodeficiency

  • Hyper-IgM syndromes

Sometime in the early 1960s, and after the finding of the IgG subclasses, there were certain connotations documented between each subclass deficiencies, which reduced the possibility of responding to certain kinds of antigens and caused recurring infections. These immunoglobulin G deficiencies can take place as isolated cases or in connection with other types of immunoglobulins and their deficiencies. Still, even when the whole IgG concentration is fine, it’s not uncommon to have one or both of the following:

  • Tremendous reduction in certain immunoglobulin G antibodies

  • Deficiencies in one or several immunoglobulin G subclasses

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