Immunoglobulin G, Subclass 1 Unit Converter

Immunoglobulin G Subclass 1 (IgG1) is the most abundant of the four IgG subclasses in human blood. IgG is the predominant antibody type in the bloodstream, and IgG1 alone accounts for about 60-70% of all circulating IgG.

IgG1 is the body's primary antibody response to protein-based threats such as bacterial toxins, viral coat proteins, and other soluble protein antigens. It plays a central role in immune defense by marking pathogens for destruction and activating the complement system.

Because IgG1 makes up such a large share of total IgG, a significant drop in IgG1 often shows up as low total IgG on routine testing. Measuring IgG subclasses individually helps pinpoint which part of the antibody response may be lacking.

IgG1 is produced by plasma cells, which are mature B lymphocytes that have undergone class-switch recombination in response to protein antigens and T helper cell signals. Plasma cells secrete IgG1 from lymph nodes, spleen, bone marrow, and mucosal-associated lymphoid tissue throughout the body.