CAMPATH-1 antigen, also known as cluster of differentiation 52 (CD52), is a glycoprotein that in humans is encoded by the CD52 gene. CD52 is present on the surface of mature lymphocytes, but not on the stem cells from which these lymphocytes were derived. It also is found on monocytes and dendritic cells. Further, it is found within the male genital tract and is present on the surface of mature sperm cells. CD52 is a peptide of 12 amino acids, anchored to glycosylphosphatidylinositol (GPI). Since it is highly negatively charged and present on sperm cells and lymphocytes, it has been conjectured that its function is anti-adhesion, allowing cells to freely move around. CD52 binds the ITIM (immunoreceptor tyrosine-based inhibitory motif)-bearing sialic acid-binding lectin SIGLEC10.
It is the protein targeted by alemtuzumab, a monoclonal antibody used for the treatment of chronic lymphocytic leukemia. A phase III trial into treatment of relapsing-remitting multiple sclerosis showed a reduction in relapse rate, but no statistically significant reduction in accumulated disability, when used as a first-line therapy.
mRNA expression analysis
Strain specific analysis of CD52 gene expression in WT and B-hCD52 mice by RT-PCR. Mouse Cd52 mRNA was detectable in splenocytes of wild-type (+/+) mice. Human CD52 mRNA was detectable only in H/H, but not in +/+ mice.
Protein expression analysis in T cells
Strain specific CD52 expression analysis in heterozygous B-hCD52 mice by flow cytometry. Splenocytes were collected from WT and heterozygous B-hCD52 (H/+) mice, and analyzed by flow cytometry with species-specific CD52 antibody. Mouse CD52 was detectable in WT mice and heterozygous B-hCD52. Human CD52 was exclusively detectable in heterozygous B-hCD52 but not WT mice.