Medicine:Glycoprotein 100

Glycoprotein 100, gp100 or Melanocyte protein PMEL is 661 amino acids long and is a type I transmembrane glycoprotein enriched in melanosomes, which are the melanin-producing organelles in melanocytes. This protein is involved in melanosome maturation.

The gp100 protein is a melanoma antigen i.e. a tumor-associated antigen.

Short fragments of it have been used to develop the gp100 cancer vaccine which is or contains gp100:209-217(210M).

Hydrophilic recombinant gp100 protein (HR-gp100) has been topically applied on human intact skin in vitro, and used as a vaccine in a mouse model. It was demonstrated that HR-gp100 permeates into human skin, and is processed and presented by human dendritic cells. In the mouse model, an HR-gp100-based vaccine triggered antigen-specific T cell responses, as shown by proliferation assays, ELISA and intracellular staining for IFN-γ.

Glycoprotein 100 (GP100) is a 661 amino acid long protein that contains differentiation antigens.[1] GP100 is a membrane bound protein that is expressed in melanocytes and pigmented cells in the retina, and in most malignant melanomas. It has widely studied to be used as a target for melanoma immunotherapy. GP100 works in functions melanogenesis, melanosome biogenesis, and melanin polymerization (Eisenberg) [2]

There are different sequences of the GP100 peptide that could be used for immunization against tumors. According to a case study, modifications of GP100 such as GP100-209 and GP100-208 have shown a greater number of antigen specific CTL's (cytotoxic T lymphocytes) which can target and kill cancer cells (Eisenberg).[3]

References

• Eisenberg, G; Machlenkin, A; Frankenburg, S; Mansura, A; Pitcovski, J; Yefenof, E; Peretz, T; Lotem, M.Sharett (2010). "Transcutaneous immunization with hydrophilic recombinant gp100 protein induces antigen-specific cellular immune response". Cell Immunol 266 (1): 98–103. doi:10.1016/j.cellimm.2010.09.003. PMID 20947070.