Immunoglobulin G (IgG) are antibody molecules. Each IgG is composed of four peptide chains — two heavy chains γ and two light chains. Each IgG has two antigen binding sites. Other immunoglobulins may be described in terms of polymers with the IgG structure considered the monomer.

IgG constitutes 75% of serum immunoglobulins in humans. IgG molecules are synthesized and secreted by plasma B cells.

IgG antibodies are involved in predominantly the secondary immune response. The presence of specific IgG, in general, corresponds to maturation of the antibody response. Human IgG Subclasses: IgG is the only isotype that can pass through the human placenta, thereby providing protection to the fetus in utero. Along with IgA secreted in the breast milk, residual IgG absorbed through the placenta provides the neonate with humoral immunity before its own immune system develops. Colostrum contains a high percentage of IgG, especially bovine colostrum.

IgG can bind to many kinds of pathogens, for example viruses, bacteria, and fungi, and protects the body against them by agglutination and immobilization, complement activation (classical pathway), opsonization for phagocytosis, and neutralization of their toxins. It also plays an important role in Antibody-dependent cell-mediated cytotoxicity(ADCC) and Intracellular antibody-mediated proteolysis, in which it binds to TRIM21 (the receptor with greatest affinity to IgG in humans) in order to direct marked virions to the proteasome in the cytosol.

Amethyst Amelia Kelly (born June 7, 1990), better known by her stage name Iggy Azalea is an Australian hip hop recording artist signed to Grand Hustle Records. She is perhaps better known for her promotional songs "Two Times", "Pu$$y" and "My World" whose music videos went viral on YouTube. On 27 September 2011, Azalea released her first project, a mixtape titled Ignorant Art, saying she made it "with the intent to make people question and redefine old ideals".

Iggy Azalea was born Amethyst Amelia Kelly in Sydney, Australia but moved with her family to Mullumbimby when she was still a baby, into a house on 12 acres that her father built by hand from mudbricks in New South Wales. Her father was a comic artist and painter and her mother a real estate agent. Azalea says her father "made her look at [art] as a teenager" which has always influenced her life and work.

Azalea began rapping at age 14. Azalea took her stage name from her family's dog while growing up. Before embarking on a solo career, Azalea formed a group with two other girls from her neighborhood: "I was like, I could be the rapper. This could be like TLC. I’ll be Left Eye." Azalea eventually decided to leave the group because the other girls weren’t taking it seriously: "I take everything I do serious. I’m too competitive."

Charlotte Aitchison, known by her stage name Charli XCX is a UK-based singer-songwriter. She released two singles in 2008 titled "Emelline/Art Bitch" and "!Francesckaar!" She was signed to This Is Music, before releasing three more singles "Stay Away", "Nuclear Seasons" and "You're the One". Charli XCX will release her debut EP "You're the One" on 12 June 2012.

Born and raised in Hertfordshire, she started her own band on the playground when she was around seven.^{[citation needed]}

Aitchison was signed to Orgy Music where she released her first two EPs "Emelline/Art Bitch" and "!Franchesckaar!" in late 2008. In 2011, she featured in Alex Metric's single "End of the World" and Starkey's single "Lost in Space" before premiering her first two songs "Stay Away" and "Nuclear Seasons". Charli XCX will also be providing a soundtrack for an up and coming indie movie called Elfie Hopkins starring Ray Winstone and his daughter Jaime Winstone. Charli XCX will release her debut EP "You're The One" through iAMSOUND Records on June 12, 2012 which will feature the singles "You're the One" and "Nuclear Seasons" plus a remix of each. She will then support Santigold and Coldplay on tour throughout Summer.