title: Expression of GPI-anchored complement regulatory proteins CD55 and CD59 differentiates two subpopulations of human CD56+ CD3- lymphocytes (NK cells).
abstract: CD55 and CD59 are both glycosylphosphatidylinositol (GPI)-anchored complement regulatory proteins found on the surface of most hemopoietic cells. Using three-color cytofluorographic analysis with antibodies recognizing CD56, CD3, and CD59 or CD55 we determined that CD56+CD3- lymphocytes (NK cells) expressed both CD55 and CD59 but at lower levels than CD3+ lymphocytes. Since the CD56+CD3- lymphocyte population is heterogeneous, we examined expression of CD55 and CD59 on selected CD56+CD3- lymphocyte populations by depleting peripheral blood leukocytes of T cells, B cells, and monocytes. Dual staining of the selected CD56+CD3- cells, which were > 95% CD56+, permitted the distiction of two subpopulations: a major CD16brightCD56dimCD55dimCD59dim subpopulation and a minor CD16dim/negCD56brightCD55brightCD59bright subpopulation. Treatment with phosphatidylinositol-specific phospholipase C released both the CD55 and CD59 antigens from the surface of CD56+CD3- cells, indicating that both are GPI-anchored, as they are on other lymphocytes. CD56+CD3- cell subpopulations were individually isolated by anti-CD55 or anti-CD16 negative selection and were functionally compared to the parent CD56+CD3- cell population. The CD16brightCD56dimCD55dimCD59dim cells killed NK targets well but did not proliferate well in response to rIL-2, whereas CD16dim/negCD56brightCD55brightCD59bright cells proliferated well in response to rIL-2 but did not kill NK targets efficiently. We conclude that all CD56+CD3- cells express some levels of the GPI-anchored proteins, CD55 and CD59, and that two CD56+CD3- subpopulations with different functional characteristics can be distinguished by the level of expression of these two antigens.
authors.affiliation: Laboratory of Infectious Diseases, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA.
authors.forename: K R
authors.initials: KR
authors.lastname: Solomon
authors.forename: M
authors.initials: M
authors.lastname: Chan
authors.forename: R W
authors.initials: RW
authors.lastname: Finberg
mesh_terms: D017252:CD3 Complex / Q000032:analysis*; D018958:CD55 Antigens / Q000032:analysis*; D019002:CD56 Antigen / Q000032:analysis*; D018957:CD59 Antigens / Q000032:analysis*; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology; D007694:Killer Cells, Natural / Q000737:chemistry*
chemical_list: D017252:CD3 Complex; D018958:CD55 Antigens; D019002:CD56 Antigen; D018957:CD59 Antigens; D007376:Interleukin-2